Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 | menu "Kernel hacking"
menu "printk and dmesg options"
config PRINTK_TIME
bool "Show timing information on printks"
depends on PRINTK
help
Selecting this option causes time stamps of the printk()
messages to be added to the output of the syslog() system
call and at the console.
The timestamp is always recorded internally, and exported
to /dev/kmsg. This flag just specifies if the timestamp should
be included, not that the timestamp is recorded.
The behavior is also controlled by the kernel command line
parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
config CONSOLE_LOGLEVEL_DEFAULT
int "Default console loglevel (1-15)"
range 1 15
default "7"
help
Default loglevel to determine what will be printed on the console.
Setting a default here is equivalent to passing in loglevel=<x> in
the kernel bootargs. loglevel=<x> continues to override whatever
value is specified here as well.
Note: This does not affect the log level of un-prefixed printk()
usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
option.
config CONSOLE_LOGLEVEL_QUIET
int "quiet console loglevel (1-15)"
range 1 15
default "4"
help
loglevel to use when "quiet" is passed on the kernel commandline.
When "quiet" is passed on the kernel commandline this loglevel
will be used as the loglevel. IOW passing "quiet" will be the
equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
config MESSAGE_LOGLEVEL_DEFAULT
int "Default message log level (1-7)"
range 1 7
default "4"
help
Default log level for printk statements with no specified priority.
This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
that are auditing their logs closely may want to set it to a lower
priority.
Note: This does not affect what message level gets printed on the console
by default. To change that, use loglevel=<x> in the kernel bootargs,
or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
config BOOT_PRINTK_DELAY
bool "Delay each boot printk message by N milliseconds"
depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
help
This build option allows you to read kernel boot messages
by inserting a short delay after each one. The delay is
specified in milliseconds on the kernel command line,
using "boot_delay=N".
It is likely that you would also need to use "lpj=M" to preset
the "loops per jiffie" value.
See a previous boot log for the "lpj" value to use for your
system, and then set "lpj=M" before setting "boot_delay=N".
NOTE: Using this option may adversely affect SMP systems.
I.e., processors other than the first one may not boot up.
BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
what it believes to be lockup conditions.
config DYNAMIC_DEBUG
bool "Enable dynamic printk() support"
default n
depends on PRINTK
depends on DEBUG_FS
help
Compiles debug level messages into the kernel, which would not
otherwise be available at runtime. These messages can then be
enabled/disabled based on various levels of scope - per source file,
function, module, format string, and line number. This mechanism
implicitly compiles in all pr_debug() and dev_dbg() calls, which
enlarges the kernel text size by about 2%.
If a source file is compiled with DEBUG flag set, any
pr_debug() calls in it are enabled by default, but can be
disabled at runtime as below. Note that DEBUG flag is
turned on by many CONFIG_*DEBUG* options.
Usage:
Dynamic debugging is controlled via the 'dynamic_debug/control' file,
which is contained in the 'debugfs' filesystem. Thus, the debugfs
filesystem must first be mounted before making use of this feature.
We refer the control file as: <debugfs>/dynamic_debug/control. This
file contains a list of the debug statements that can be enabled. The
format for each line of the file is:
filename:lineno [module]function flags format
filename : source file of the debug statement
lineno : line number of the debug statement
module : module that contains the debug statement
function : function that contains the debug statement
flags : '=p' means the line is turned 'on' for printing
format : the format used for the debug statement
From a live system:
nullarbor:~ # cat <debugfs>/dynamic_debug/control
# filename:lineno [module]function flags format
fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
Example usage:
// enable the message at line 1603 of file svcsock.c
nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
<debugfs>/dynamic_debug/control
// enable all the messages in file svcsock.c
nullarbor:~ # echo -n 'file svcsock.c +p' >
<debugfs>/dynamic_debug/control
// enable all the messages in the NFS server module
nullarbor:~ # echo -n 'module nfsd +p' >
<debugfs>/dynamic_debug/control
// enable all 12 messages in the function svc_process()
nullarbor:~ # echo -n 'func svc_process +p' >
<debugfs>/dynamic_debug/control
// disable all 12 messages in the function svc_process()
nullarbor:~ # echo -n 'func svc_process -p' >
<debugfs>/dynamic_debug/control
See Documentation/admin-guide/dynamic-debug-howto.rst for additional
information.
endmenu # "printk and dmesg options"
menu "Compile-time checks and compiler options"
config DEBUG_INFO
bool "Compile the kernel with debug info"
depends on DEBUG_KERNEL && !COMPILE_TEST
help
If you say Y here the resulting kernel image will include
debugging info resulting in a larger kernel image.
This adds debug symbols to the kernel and modules (gcc -g), and
is needed if you intend to use kernel crashdump or binary object
tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Say Y here only if you plan to debug the kernel.
If unsure, say N.
config DEBUG_INFO_REDUCED
bool "Reduce debugging information"
depends on DEBUG_INFO
help
If you say Y here gcc is instructed to generate less debugging
information for structure types. This means that tools that
need full debugging information (like kgdb or systemtap) won't
be happy. But if you merely need debugging information to
resolve line numbers there is no loss. Advantage is that
build directory object sizes shrink dramatically over a full
DEBUG_INFO build and compile times are reduced too.
Only works with newer gcc versions.
config DEBUG_INFO_SPLIT
bool "Produce split debuginfo in .dwo files"
depends on DEBUG_INFO
help
Generate debug info into separate .dwo files. This significantly
reduces the build directory size for builds with DEBUG_INFO,
because it stores the information only once on disk in .dwo
files instead of multiple times in object files and executables.
In addition the debug information is also compressed.
Requires recent gcc (4.7+) and recent gdb/binutils.
Any tool that packages or reads debug information would need
to know about the .dwo files and include them.
Incompatible with older versions of ccache.
config DEBUG_INFO_DWARF4
bool "Generate dwarf4 debuginfo"
depends on DEBUG_INFO
help
Generate dwarf4 debug info. This requires recent versions
of gcc and gdb. It makes the debug information larger.
But it significantly improves the success of resolving
variables in gdb on optimized code.
config GDB_SCRIPTS
bool "Provide GDB scripts for kernel debugging"
depends on DEBUG_INFO
help
This creates the required links to GDB helper scripts in the
build directory. If you load vmlinux into gdb, the helper
scripts will be automatically imported by gdb as well, and
additional functions are available to analyze a Linux kernel
instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
for further details.
config ENABLE_MUST_CHECK
bool "Enable __must_check logic"
default y
help
Enable the __must_check logic in the kernel build. Disable this to
suppress the "warning: ignoring return value of 'foo', declared with
attribute warn_unused_result" messages.
config FRAME_WARN
int "Warn for stack frames larger than (needs gcc 4.4)"
range 0 8192
default 3072 if KASAN_EXTRA
default 2048 if GCC_PLUGIN_LATENT_ENTROPY
default 1280 if (!64BIT && PARISC)
default 1024 if (!64BIT && !PARISC)
default 2048 if 64BIT
help
Tell gcc to warn at build time for stack frames larger than this.
Setting this too low will cause a lot of warnings.
Setting it to 0 disables the warning.
Requires gcc 4.4
config STRIP_ASM_SYMS
bool "Strip assembler-generated symbols during link"
default n
help
Strip internal assembler-generated symbols during a link (symbols
that look like '.Lxxx') so they don't pollute the output of
get_wchan() and suchlike.
config READABLE_ASM
bool "Generate readable assembler code"
depends on DEBUG_KERNEL
help
Disable some compiler optimizations that tend to generate human unreadable
assembler output. This may make the kernel slightly slower, but it helps
to keep kernel developers who have to stare a lot at assembler listings
sane.
config UNUSED_SYMBOLS
bool "Enable unused/obsolete exported symbols"
default y if X86
help
Unused but exported symbols make the kernel needlessly bigger. For
that reason most of these unused exports will soon be removed. This
option is provided temporarily to provide a transition period in case
some external kernel module needs one of these symbols anyway. If you
encounter such a case in your module, consider if you are actually
using the right API. (rationale: since nobody in the kernel is using
this in a module, there is a pretty good chance it's actually the
wrong interface to use). If you really need the symbol, please send a
mail to the linux kernel mailing list mentioning the symbol and why
you really need it, and what the merge plan to the mainline kernel for
your module is.
config PAGE_OWNER
bool "Track page owner"
depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
select DEBUG_FS
select STACKTRACE
select STACKDEPOT
select PAGE_EXTENSION
help
This keeps track of what call chain is the owner of a page, may
help to find bare alloc_page(s) leaks. Even if you include this
feature on your build, it is disabled in default. You should pass
"page_owner=on" to boot parameter in order to enable it. Eats
a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
for user-space helper.
If unsure, say N.
config DEBUG_FS
bool "Debug Filesystem"
help
debugfs is a virtual file system that kernel developers use to put
debugging files into. Enable this option to be able to read and
write to these files.
For detailed documentation on the debugfs API, see
Documentation/filesystems/.
If unsure, say N.
config HEADERS_CHECK
bool "Run 'make headers_check' when building vmlinux"
depends on !UML
help
This option will extract the user-visible kernel headers whenever
building the kernel, and will run basic sanity checks on them to
ensure that exported files do not attempt to include files which
were not exported, etc.
If you're making modifications to header files which are
relevant for userspace, say 'Y', and check the headers
exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
your build tree), to make sure they're suitable.
config DEBUG_SECTION_MISMATCH
bool "Enable full Section mismatch analysis"
help
The section mismatch analysis checks if there are illegal
references from one section to another section.
During linktime or runtime, some sections are dropped;
any use of code/data previously in these sections would
most likely result in an oops.
In the code, functions and variables are annotated with
__init,, etc. (see the full list in include/linux/init.h),
which results in the code/data being placed in specific sections.
The section mismatch analysis is always performed after a full
kernel build, and enabling this option causes the following
additional steps to occur:
- Add the option -fno-inline-functions-called-once to gcc commands.
When inlining a function annotated with __init in a non-init
function, we would lose the section information and thus
the analysis would not catch the illegal reference.
This option tells gcc to inline less (but it does result in
a larger kernel).
- Run the section mismatch analysis for each module/built-in.a file.
When we run the section mismatch analysis on vmlinux.o, we
lose valuable information about where the mismatch was
introduced.
Running the analysis for each module/built-in.a file
tells where the mismatch happens much closer to the
source. The drawback is that the same mismatch is
reported at least twice.
- Enable verbose reporting from modpost in order to help resolve
the section mismatches that are reported.
config SECTION_MISMATCH_WARN_ONLY
bool "Make section mismatch errors non-fatal"
default y
help
If you say N here, the build process will fail if there are any
section mismatch, instead of just throwing warnings.
If unsure, say Y.
#
# Select this config option from the architecture Kconfig, if it
# is preferred to always offer frame pointers as a config
# option on the architecture (regardless of KERNEL_DEBUG):
#
config ARCH_WANT_FRAME_POINTERS
bool
config FRAME_POINTER
bool "Compile the kernel with frame pointers"
depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
help
If you say Y here the resulting kernel image will be slightly
larger and slower, but it gives very useful debugging information
in case of kernel bugs. (precise oopses/stacktraces/warnings)
config STACK_VALIDATION
bool "Compile-time stack metadata validation"
depends on HAVE_STACK_VALIDATION
default n
help
Add compile-time checks to validate stack metadata, including frame
pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
that runtime stack traces are more reliable.
This is also a prerequisite for generation of ORC unwind data, which
is needed for CONFIG_UNWINDER_ORC.
For more information, see
tools/objtool/Documentation/stack-validation.txt.
config DEBUG_FORCE_WEAK_PER_CPU
bool "Force weak per-cpu definitions"
depends on DEBUG_KERNEL
help
s390 and alpha require percpu variables in modules to be
defined weak to work around addressing range issue which
puts the following two restrictions on percpu variable
definitions.
1. percpu symbols must be unique whether static or not
2. percpu variables can't be defined inside a function
To ensure that generic code follows the above rules, this
option forces all percpu variables to be defined as weak.
endmenu # "Compiler options"
config MAGIC_SYSRQ
bool "Magic SysRq key"
depends on !UML
help
If you say Y here, you will have some control over the system even
if the system crashes for example during kernel debugging (e.g., you
will be able to flush the buffer cache to disk, reboot the system
immediately or dump some status information). This is accomplished
by pressing various keys while holding SysRq (Alt+PrintScreen). It
also works on a serial console (on PC hardware at least), if you
send a BREAK and then within 5 seconds a command keypress. The
keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
Don't say Y unless you really know what this hack does.
config MAGIC_SYSRQ_DEFAULT_ENABLE
hex "Enable magic SysRq key functions by default"
depends on MAGIC_SYSRQ
default 0x1
help
Specifies which SysRq key functions are enabled by default.
This may be set to 1 or 0 to enable or disable them all, or
to a bitmask as described in Documentation/admin-guide/sysrq.rst.
config MAGIC_SYSRQ_SERIAL
bool "Enable magic SysRq key over serial"
depends on MAGIC_SYSRQ
default y
help
Many embedded boards have a disconnected TTL level serial which can
generate some garbage that can lead to spurious false sysrq detects.
This option allows you to decide whether you want to enable the
magic SysRq key.
config DEBUG_KERNEL
bool "Kernel debugging"
help
Say Y here if you are developing drivers or trying to debug and
identify kernel problems.
menu "Memory Debugging"
source "mm/Kconfig.debug"
config DEBUG_OBJECTS
bool "Debug object operations"
depends on DEBUG_KERNEL
help
If you say Y here, additional code will be inserted into the
kernel to track the life time of various objects and validate
the operations on those objects.
config DEBUG_OBJECTS_SELFTEST
bool "Debug objects selftest"
depends on DEBUG_OBJECTS
help
This enables the selftest of the object debug code.
config DEBUG_OBJECTS_FREE
bool "Debug objects in freed memory"
depends on DEBUG_OBJECTS
help
This enables checks whether a k/v free operation frees an area
which contains an object which has not been deactivated
properly. This can make kmalloc/kfree-intensive workloads
much slower.
config DEBUG_OBJECTS_TIMERS
bool "Debug timer objects"
depends on DEBUG_OBJECTS
help
If you say Y here, additional code will be inserted into the
timer routines to track the life time of timer objects and
validate the timer operations.
config DEBUG_OBJECTS_WORK
bool "Debug work objects"
depends on DEBUG_OBJECTS
help
If you say Y here, additional code will be inserted into the
work queue routines to track the life time of work objects and
validate the work operations.
config DEBUG_OBJECTS_RCU_HEAD
bool "Debug RCU callbacks objects"
depends on DEBUG_OBJECTS
help
Enable this to turn on debugging of RCU list heads (call_rcu() usage).
config DEBUG_OBJECTS_PERCPU_COUNTER
bool "Debug percpu counter objects"
depends on DEBUG_OBJECTS
help
If you say Y here, additional code will be inserted into the
percpu counter routines to track the life time of percpu counter
objects and validate the percpu counter operations.
config DEBUG_OBJECTS_ENABLE_DEFAULT
int "debug_objects bootup default value (0-1)"
range 0 1
default "1"
depends on DEBUG_OBJECTS
help
Debug objects boot parameter default value
config DEBUG_SLAB
bool "Debug slab memory allocations"
depends on DEBUG_KERNEL && SLAB
help
Say Y here to have the kernel do limited verification on memory
allocation as well as poisoning memory on free to catch use of freed
memory. This can make kmalloc/kfree-intensive workloads much slower.
config DEBUG_SLAB_LEAK
bool "Memory leak debugging"
depends on DEBUG_SLAB
config SLUB_DEBUG_ON
bool "SLUB debugging on by default"
depends on SLUB && SLUB_DEBUG
default n
help
Boot with debugging on by default. SLUB boots by default with
the runtime debug capabilities switched off. Enabling this is
equivalent to specifying the "slub_debug" parameter on boot.
There is no support for more fine grained debug control like
possible with slub_debug=xxx. SLUB debugging may be switched
off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
"slub_debug=-".
config SLUB_STATS
default n
bool "Enable SLUB performance statistics"
depends on SLUB && SYSFS
help
SLUB statistics are useful to debug SLUBs allocation behavior in
order find ways to optimize the allocator. This should never be
enabled for production use since keeping statistics slows down
the allocator by a few percentage points. The slabinfo command
supports the determination of the most active slabs to figure
out which slabs are relevant to a particular load.
Try running: slabinfo -DA
config HAVE_DEBUG_KMEMLEAK
bool
config DEBUG_KMEMLEAK
bool "Kernel memory leak detector"
depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
select DEBUG_FS
select STACKTRACE if STACKTRACE_SUPPORT
select KALLSYMS
select CRC32
help
Say Y here if you want to enable the memory leak
detector. The memory allocation/freeing is traced in a way
similar to the Boehm's conservative garbage collector, the
difference being that the orphan objects are not freed but
only shown in /sys/kernel/debug/kmemleak. Enabling this
feature will introduce an overhead to memory
allocations. See Documentation/dev-tools/kmemleak.rst for more
details.
Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
of finding leaks due to the slab objects poisoning.
In order to access the kmemleak file, debugfs needs to be
mounted (usually at /sys/kernel/debug).
config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
int "Maximum kmemleak early log entries"
depends on DEBUG_KMEMLEAK
range 200 40000
default 400
help
Kmemleak must track all the memory allocations to avoid
reporting false positives. Since memory may be allocated or
freed before kmemleak is initialised, an early log buffer is
used to store these actions. If kmemleak reports "early log
buffer exceeded", please increase this value.
config DEBUG_KMEMLEAK_TEST
tristate "Simple test for the kernel memory leak detector"
depends on DEBUG_KMEMLEAK && m
help
This option enables a module that explicitly leaks memory.
If unsure, say N.
config DEBUG_KMEMLEAK_DEFAULT_OFF
bool "Default kmemleak to off"
depends on DEBUG_KMEMLEAK
help
Say Y here to disable kmemleak by default. It can then be enabled
on the command line via kmemleak=on.
config DEBUG_KMEMLEAK_AUTO_SCAN
bool "Enable kmemleak auto scan thread on boot up"
default y
depends on DEBUG_KMEMLEAK
help
Depending on the cpu, kmemleak scan may be cpu intensive and can
stall user tasks at times. This option enables/disables automatic
kmemleak scan at boot up.
Say N here to disable kmemleak auto scan thread to stop automatic
scanning. Disabling this option disables automatic reporting of
memory leaks.
If unsure, say Y.
config DEBUG_STACK_USAGE
bool "Stack utilization instrumentation"
depends on DEBUG_KERNEL && !IA64
help
Enables the display of the minimum amount of free stack which each
task has ever had available in the sysrq-T and sysrq-P debug output.
This option will slow down process creation somewhat.
config DEBUG_VM
bool "Debug VM"
depends on DEBUG_KERNEL
help
Enable this to turn on extended checks in the virtual-memory system
that may impact performance.
If unsure, say N.
config DEBUG_VM_VMACACHE
bool "Debug VMA caching"
depends on DEBUG_VM
help
Enable this to turn on VMA caching debug information. Doing so
can cause significant overhead, so only enable it in non-production
environments.
If unsure, say N.
config DEBUG_VM_RB
bool "Debug VM red-black trees"
depends on DEBUG_VM
help
Enable VM red-black tree debugging information and extra validations.
If unsure, say N.
config DEBUG_VM_PGFLAGS
bool "Debug page-flags operations"
depends on DEBUG_VM
help
Enables extra validation on page flags operations.
If unsure, say N.
config ARCH_HAS_DEBUG_VIRTUAL
bool
config DEBUG_VIRTUAL
bool "Debug VM translations"
depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
help
Enable some costly sanity checks in virtual to page code. This can
catch mistakes with virt_to_page() and friends.
If unsure, say N.
config DEBUG_NOMMU_REGIONS
bool "Debug the global anon/private NOMMU mapping region tree"
depends on DEBUG_KERNEL && !MMU
help
This option causes the global tree of anonymous and private mapping
regions to be regularly checked for invalid topology.
config DEBUG_MEMORY_INIT
bool "Debug memory initialisation" if EXPERT
default !EXPERT
help
Enable this for additional checks during memory initialisation.
The sanity checks verify aspects of the VM such as the memory model
and other information provided by the architecture. Verbose
information will be printed at KERN_DEBUG loglevel depending
on the mminit_loglevel= command-line option.
If unsure, say Y
config MEMORY_NOTIFIER_ERROR_INJECT
tristate "Memory hotplug notifier error injection module"
depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
help
This option provides the ability to inject artificial errors to
memory hotplug notifier chain callbacks. It is controlled through
debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
If the notifier call chain should be failed with some events
notified, write the error code to "actions/<notifier event>/error".
Example: Inject memory hotplug offline error (-12 == -ENOMEM)
# cd /sys/kernel/debug/notifier-error-inject/memory
# echo -12 > actions/MEM_GOING_OFFLINE/error
# echo offline > /sys/devices/system/memory/memoryXXX/state
bash: echo: write error: Cannot allocate memory
To compile this code as a module, choose M here: the module will
be called memory-notifier-error-inject.
If unsure, say N.
config DEBUG_PER_CPU_MAPS
bool "Debug access to per_cpu maps"
depends on DEBUG_KERNEL
depends on SMP
help
Say Y to verify that the per_cpu map being accessed has
been set up. This adds a fair amount of code to kernel memory
and decreases performance.
Say N if unsure.
config DEBUG_HIGHMEM
bool "Highmem debugging"
depends on DEBUG_KERNEL && HIGHMEM
help
This option enables additional error checking for high memory
systems. Disable for production systems.
config HAVE_DEBUG_STACKOVERFLOW
bool
config DEBUG_STACKOVERFLOW
bool "Check for stack overflows"
depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
---help---
Say Y here if you want to check for overflows of kernel, IRQ
and exception stacks (if your architecture uses them). This
option will show detailed messages if free stack space drops
below a certain limit.
These kinds of bugs usually occur when call-chains in the
kernel get too deep, especially when interrupts are
involved.
Use this in cases where you see apparently random memory
corruption, especially if it appears in 'struct thread_info'
If in doubt, say "N".
source "lib/Kconfig.kasan"
endmenu # "Memory Debugging"
config ARCH_HAS_KCOV
bool
help
KCOV does not have any arch-specific code, but currently it is enabled
only for x86_64. KCOV requires testing on other archs, and most likely
disabling of instrumentation for some early boot code.
config CC_HAS_SANCOV_TRACE_PC
def_bool $(cc-option,-fsanitize-coverage=trace-pc)
config KCOV
bool "Code coverage for fuzzing"
depends on ARCH_HAS_KCOV
depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
select DEBUG_FS
select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
help
KCOV exposes kernel code coverage information in a form suitable
for coverage-guided fuzzing (randomized testing).
If RANDOMIZE_BASE is enabled, PC values will not be stable across
different machines and across reboots. If you need stable PC values,
disable RANDOMIZE_BASE.
For more details, see Documentation/dev-tools/kcov.rst.
config KCOV_ENABLE_COMPARISONS
bool "Enable comparison operands collection by KCOV"
depends on KCOV
depends on $(cc-option,-fsanitize-coverage=trace-cmp)
help
KCOV also exposes operands of every comparison in the instrumented
code along with operand sizes and PCs of the comparison instructions.
These operands can be used by fuzzing engines to improve the quality
of fuzzing coverage.
config KCOV_INSTRUMENT_ALL
bool "Instrument all code by default"
depends on KCOV
default y
help
If you are doing generic system call fuzzing (like e.g. syzkaller),
then you will want to instrument the whole kernel and you should
say y here. If you are doing more targeted fuzzing (like e.g.
filesystem fuzzing with AFL) then you will want to enable coverage
for more specific subsets of files, and should say n here.
config DEBUG_SHIRQ
bool "Debug shared IRQ handlers"
depends on DEBUG_KERNEL
help
Enable this to generate a spurious interrupt as soon as a shared
interrupt handler is registered, and just before one is deregistered.
Drivers ought to be able to handle interrupts coming in at those
points; some don't and need to be caught.
menu "Debug Lockups and Hangs"
config LOCKUP_DETECTOR
bool
config SOFTLOCKUP_DETECTOR
bool "Detect Soft Lockups"
depends on DEBUG_KERNEL && !S390
select LOCKUP_DETECTOR
help
Say Y here to enable the kernel to act as a watchdog to detect
soft lockups.
Softlockups are bugs that cause the kernel to loop in kernel
mode for more than 20 seconds, without giving other tasks a
chance to run. The current stack trace is displayed upon
detection and the system will stay locked up.
config BOOTPARAM_SOFTLOCKUP_PANIC
bool "Panic (Reboot) On Soft Lockups"
depends on SOFTLOCKUP_DETECTOR
help
Say Y here to enable the kernel to panic on "soft lockups",
which are bugs that cause the kernel to loop in kernel
mode for more than 20 seconds (configurable using the watchdog_thresh
sysctl), without giving other tasks a chance to run.
The panic can be used in combination with panic_timeout,
to cause the system to reboot automatically after a
lockup has been detected. This feature is useful for
high-availability systems that have uptime guarantees and
where a lockup must be resolved ASAP.
Say N if unsure.
config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
int
depends on SOFTLOCKUP_DETECTOR
range 0 1
default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
config HARDLOCKUP_DETECTOR_PERF
bool
select SOFTLOCKUP_DETECTOR
#
# Enables a timestamp based low pass filter to compensate for perf based
# hard lockup detection which runs too fast due to turbo modes.
#
config HARDLOCKUP_CHECK_TIMESTAMP
bool
#
# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
# lockup detector rather than the perf based detector.
#
config HARDLOCKUP_DETECTOR
bool "Detect Hard Lockups"
depends on DEBUG_KERNEL && !S390
depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
select LOCKUP_DETECTOR
select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
help
Say Y here to enable the kernel to act as a watchdog to detect
hard lockups.
Hardlockups are bugs that cause the CPU to loop in kernel mode
for more than 10 seconds, without letting other interrupts have a
chance to run. The current stack trace is displayed upon detection
and the system will stay locked up.
config BOOTPARAM_HARDLOCKUP_PANIC
bool "Panic (Reboot) On Hard Lockups"
depends on HARDLOCKUP_DETECTOR
help
Say Y here to enable the kernel to panic on "hard lockups",
which are bugs that cause the kernel to loop in kernel
mode with interrupts disabled for more than 10 seconds (configurable
using the watchdog_thresh sysctl).
Say N if unsure.
config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
int
depends on HARDLOCKUP_DETECTOR
range 0 1
default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
default 1 if BOOTPARAM_HARDLOCKUP_PANIC
config DETECT_HUNG_TASK
bool "Detect Hung Tasks"
depends on DEBUG_KERNEL
default SOFTLOCKUP_DETECTOR
help
Say Y here to enable the kernel to detect "hung tasks",
which are bugs that cause the task to be stuck in
uninterruptible "D" state indefinitely.
When a hung task is detected, the kernel will print the
current stack trace (which you should report), but the
task will stay in uninterruptible state. If lockdep is
enabled then all held locks will also be reported. This
feature has negligible overhead.
config DEFAULT_HUNG_TASK_TIMEOUT
int "Default timeout for hung task detection (in seconds)"
depends on DETECT_HUNG_TASK
default 120
help
This option controls the default timeout (in seconds) used
to determine when a task has become non-responsive and should
be considered hung.
It can be adjusted at runtime via the kernel.hung_task_timeout_secs
sysctl or by writing a value to
/proc/sys/kernel/hung_task_timeout_secs.
A timeout of 0 disables the check. The default is two minutes.
Keeping the default should be fine in most cases.
config BOOTPARAM_HUNG_TASK_PANIC
bool "Panic (Reboot) On Hung Tasks"
depends on DETECT_HUNG_TASK
help
Say Y here to enable the kernel to panic on "hung tasks",
which are bugs that cause the kernel to leave a task stuck
in uninterruptible "D" state.
The panic can be used in combination with panic_timeout,
to cause the system to reboot automatically after a
hung task has been detected. This feature is useful for
high-availability systems that have uptime guarantees and
where a hung tasks must be resolved ASAP.
Say N if unsure.
config BOOTPARAM_HUNG_TASK_PANIC_VALUE
int
depends on DETECT_HUNG_TASK
range 0 1
default 0 if !BOOTPARAM_HUNG_TASK_PANIC
default 1 if BOOTPARAM_HUNG_TASK_PANIC
config WQ_WATCHDOG
bool "Detect Workqueue Stalls"
depends on DEBUG_KERNEL
help
Say Y here to enable stall detection on workqueues. If a
worker pool doesn't make forward progress on a pending work
item for over a given amount of time, 30s by default, a
warning message is printed along with dump of workqueue
state. This can be configured through kernel parameter
"workqueue.watchdog_thresh" and its sysfs counterpart.
endmenu # "Debug lockups and hangs"
config PANIC_ON_OOPS
bool "Panic on Oops"
help
Say Y here to enable the kernel to panic when it oopses. This
has the same effect as setting oops=panic on the kernel command
line.
This feature is useful to ensure that the kernel does not do
anything erroneous after an oops which could result in data
corruption or other issues.
Say N if unsure.
config PANIC_ON_OOPS_VALUE
int
range 0 1
default 0 if !PANIC_ON_OOPS
default 1 if PANIC_ON_OOPS
config PANIC_TIMEOUT
int "panic timeout"
default 0
help
Set the timeout value (in seconds) until a reboot occurs when the
the kernel panics. If n = 0, then we wait forever. A timeout
value n > 0 will wait n seconds before rebooting, while a timeout
value n < 0 will reboot immediately.
config SCHED_DEBUG
bool "Collect scheduler debugging info"
depends on DEBUG_KERNEL && PROC_FS
default y
help
If you say Y here, the /proc/sched_debug file will be provided
that can help debug the scheduler. The runtime overhead of this
option is minimal.
config SCHED_INFO
bool
default n
config SCHEDSTATS
bool "Collect scheduler statistics"
depends on DEBUG_KERNEL && PROC_FS
select SCHED_INFO
help
If you say Y here, additional code will be inserted into the
scheduler and related routines to collect statistics about
scheduler behavior and provide them in /proc/schedstat. These
stats may be useful for both tuning and debugging the scheduler
If you aren't debugging the scheduler or trying to tune a specific
application, you can say N to avoid the very slight overhead
this adds.
config SCHED_STACK_END_CHECK
bool "Detect stack corruption on calls to schedule()"
depends on DEBUG_KERNEL
default n
help
This option checks for a stack overrun on calls to schedule().
If the stack end location is found to be over written always panic as
the content of the corrupted region can no longer be trusted.
This is to ensure no erroneous behaviour occurs which could result in
data corruption or a sporadic crash at a later stage once the region
is examined. The runtime overhead introduced is minimal.
config DEBUG_TIMEKEEPING
bool "Enable extra timekeeping sanity checking"
help
This option will enable additional timekeeping sanity checks
which may be helpful when diagnosing issues where timekeeping
problems are suspected.
This may include checks in the timekeeping hotpaths, so this
option may have a (very small) performance impact to some
workloads.
If unsure, say N.
config DEBUG_PREEMPT
bool "Debug preemptible kernel"
depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
default y
help
If you say Y here then the kernel will use a debug variant of the
commonly used smp_processor_id() function and will print warnings
if kernel code uses it in a preemption-unsafe way. Also, the kernel
will detect preemption count underflows.
menu "Lock Debugging (spinlocks, mutexes, etc...)"
config LOCK_DEBUGGING_SUPPORT
bool
depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
default y
config PROVE_LOCKING
bool "Lock debugging: prove locking correctness"
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select LOCKDEP
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
select DEBUG_WW_MUTEX_SLOWPATH
select DEBUG_LOCK_ALLOC
select TRACE_IRQFLAGS
default n
help
This feature enables the kernel to prove that all locking
that occurs in the kernel runtime is mathematically
correct: that under no circumstance could an arbitrary (and
not yet triggered) combination of observed locking
sequences (on an arbitrary number of CPUs, running an
arbitrary number of tasks and interrupt contexts) cause a
deadlock.
In short, this feature enables the kernel to report locking
related deadlocks before they actually occur.
The proof does not depend on how hard and complex a
deadlock scenario would be to trigger: how many
participant CPUs, tasks and irq-contexts would be needed
for it to trigger. The proof also does not depend on
timing: if a race and a resulting deadlock is possible
theoretically (no matter how unlikely the race scenario
is), it will be proven so and will immediately be
reported by the kernel (once the event is observed that
makes the deadlock theoretically possible).
If a deadlock is impossible (i.e. the locking rules, as
observed by the kernel, are mathematically correct), the
kernel reports nothing.
NOTE: this feature can also be enabled for rwlocks, mutexes
and rwsems - in which case all dependencies between these
different locking variants are observed and mapped too, and
the proof of observed correctness is also maintained for an
arbitrary combination of these separate locking variants.
For more details, see Documentation/locking/lockdep-design.txt.
config LOCK_STAT
bool "Lock usage statistics"
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select LOCKDEP
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
select DEBUG_LOCK_ALLOC
default n
help
This feature enables tracking lock contention points
For more details, see Documentation/locking/lockstat.txt
This also enables lock events required by "perf lock",
subcommand of perf.
If you want to use "perf lock", you also need to turn on
CONFIG_EVENT_TRACING.
CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
(CONFIG_LOCKDEP defines "acquire" and "release" events.)
config DEBUG_RT_MUTEXES
bool "RT Mutex debugging, deadlock detection"
depends on DEBUG_KERNEL && RT_MUTEXES
help
This allows rt mutex semantics violations and rt mutex related
deadlocks (lockups) to be detected and reported automatically.
config DEBUG_SPINLOCK
bool "Spinlock and rw-lock debugging: basic checks"
depends on DEBUG_KERNEL
select UNINLINE_SPIN_UNLOCK
help
Say Y here and build SMP to catch missing spinlock initialization
and certain other kinds of spinlock errors commonly made. This is
best used in conjunction with the NMI watchdog so that spinlock
deadlocks are also debuggable.
config DEBUG_MUTEXES
bool "Mutex debugging: basic checks"
depends on DEBUG_KERNEL
help
This feature allows mutex semantics violations to be detected and
reported.
config DEBUG_WW_MUTEX_SLOWPATH
bool "Wait/wound mutex debugging: Slowpath testing"
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select DEBUG_LOCK_ALLOC
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
help
This feature enables slowpath testing for w/w mutex users by
injecting additional -EDEADLK wound/backoff cases. Together with
the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
will test all possible w/w mutex interface abuse with the
exception of simply not acquiring all the required locks.
Note that this feature can introduce significant overhead, so
it really should not be enabled in a production or distro kernel,
even a debug kernel. If you are a driver writer, enable it. If
you are a distro, do not.
config DEBUG_RWSEMS
bool "RW Semaphore debugging: basic checks"
depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER
help
This debugging feature allows mismatched rw semaphore locks and unlocks
to be detected and reported.
config DEBUG_LOCK_ALLOC
bool "Lock debugging: detect incorrect freeing of live locks"
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
select LOCKDEP
help
This feature will check whether any held lock (spinlock, rwlock,
mutex or rwsem) is incorrectly freed by the kernel, via any of the
memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
vfree(), etc.), whether a live lock is incorrectly reinitialized via
spin_lock_init()/mutex_init()/etc., or whether there is any lock
held during task exit.
config LOCKDEP
bool
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select STACKTRACE
select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
select KALLSYMS
select KALLSYMS_ALL
config LOCKDEP_SMALL
bool
config DEBUG_LOCKDEP
bool "Lock dependency engine debugging"
depends on DEBUG_KERNEL && LOCKDEP
help
If you say Y here, the lock dependency engine will do
additional runtime checks to debug itself, at the price
of more runtime overhead.
config DEBUG_ATOMIC_SLEEP
bool "Sleep inside atomic section checking"
select PREEMPT_COUNT
depends on DEBUG_KERNEL
depends on !ARCH_NO_PREEMPT
help
If you say Y here, various routines which may sleep will become very
noisy if they are called inside atomic sections: when a spinlock is
held, inside an rcu read side critical section, inside preempt disabled
sections, inside an interrupt, etc...
config DEBUG_LOCKING_API_SELFTESTS
bool "Locking API boot-time self-tests"
depends on DEBUG_KERNEL
help
Say Y here if you want the kernel to run a short self-test during
bootup. The self-test checks whether common types of locking bugs
are detected by debugging mechanisms or not. (if you disable
lock debugging then those bugs wont be detected of course.)
The following locking APIs are covered: spinlocks, rwlocks,
mutexes and rwsems.
config LOCK_TORTURE_TEST
tristate "torture tests for locking"
depends on DEBUG_KERNEL
select TORTURE_TEST
help
This option provides a kernel module that runs torture tests
on kernel locking primitives. The kernel module may be built
after the fact on the running kernel to be tested, if desired.
Say Y here if you want kernel locking-primitive torture tests
to be built into the kernel.
Say M if you want these torture tests to build as a module.
Say N if you are unsure.
config WW_MUTEX_SELFTEST
tristate "Wait/wound mutex selftests"
help
This option provides a kernel module that runs tests on the
on the struct ww_mutex locking API.
It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
with this test harness.
Say M if you want these self tests to build as a module.
Say N if you are unsure.
endmenu # lock debugging
config TRACE_IRQFLAGS
bool
help
Enables hooks to interrupt enabling and disabling for
either tracing or lock debugging.
config STACKTRACE
bool "Stack backtrace support"
depends on STACKTRACE_SUPPORT
help
This option causes the kernel to create a /proc/pid/stack for
every process, showing its current stack trace.
It is also used by various kernel debugging features that require
stack trace generation.
config WARN_ALL_UNSEEDED_RANDOM
bool "Warn for all uses of unseeded randomness"
default n
help
Some parts of the kernel contain bugs relating to their use of
cryptographically secure random numbers before it's actually possible
to generate those numbers securely. This setting ensures that these
flaws don't go unnoticed, by enabling a message, should this ever
occur. This will allow people with obscure setups to know when things
are going wrong, so that they might contact developers about fixing
it.
Unfortunately, on some models of some architectures getting
a fully seeded CRNG is extremely difficult, and so this can
result in dmesg getting spammed for a surprisingly long
time. This is really bad from a security perspective, and
so architecture maintainers really need to do what they can
to get the CRNG seeded sooner after the system is booted.
However, since users cannot do anything actionable to
address this, by default the kernel will issue only a single
warning for the first use of unseeded randomness.
Say Y here if you want to receive warnings for all uses of
unseeded randomness. This will be of use primarily for
those developers interested in improving the security of
Linux kernels running on their architecture (or
subarchitecture).
config DEBUG_KOBJECT
bool "kobject debugging"
depends on DEBUG_KERNEL
help
If you say Y here, some extra kobject debugging messages will be sent
to the syslog.
config DEBUG_KOBJECT_RELEASE
bool "kobject release debugging"
depends on DEBUG_OBJECTS_TIMERS
help
kobjects are reference counted objects. This means that their
last reference count put is not predictable, and the kobject can
live on past the point at which a driver decides to drop it's
initial reference to the kobject gained on allocation. An
example of this would be a struct device which has just been
unregistered.
However, some buggy drivers assume that after such an operation,
the memory backing the kobject can be immediately freed. This
goes completely against the principles of a refcounted object.
If you say Y here, the kernel will delay the release of kobjects
on the last reference count to improve the visibility of this
kind of kobject release bug.
config HAVE_DEBUG_BUGVERBOSE
bool
config DEBUG_BUGVERBOSE
bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
default y
help
Say Y here to make BUG() panics output the file name and line number
of the BUG call as well as the EIP and oops trace. This aids
debugging but costs about 70-100K of memory.
config DEBUG_LIST
bool "Debug linked list manipulation"
depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
help
Enable this to turn on extended checks in the linked-list
walking routines.
If unsure, say N.
config DEBUG_PI_LIST
bool "Debug priority linked list manipulation"
depends on DEBUG_KERNEL
help
Enable this to turn on extended checks in the priority-ordered
linked-list (plist) walking routines. This checks the entire
list multiple times during each manipulation.
If unsure, say N.
config DEBUG_SG
bool "Debug SG table operations"
depends on DEBUG_KERNEL
help
Enable this to turn on checks on scatter-gather tables. This can
help find problems with drivers that do not properly initialize
their sg tables.
If unsure, say N.
config DEBUG_NOTIFIERS
bool "Debug notifier call chains"
depends on DEBUG_KERNEL
help
Enable this to turn on sanity checking for notifier call chains.
This is most useful for kernel developers to make sure that
modules properly unregister themselves from notifier chains.
This is a relatively cheap check but if you care about maximum
performance, say N.
config DEBUG_CREDENTIALS
bool "Debug credential management"
depends on DEBUG_KERNEL
help
Enable this to turn on some debug checking for credential
management. The additional code keeps track of the number of
pointers from task_structs to any given cred struct, and checks to
see that this number never exceeds the usage count of the cred
struct.
Furthermore, if SELinux is enabled, this also checks that the
security pointer in the cred struct is never seen to be invalid.
If unsure, say N.
source "kernel/rcu/Kconfig.debug"
config DEBUG_WQ_FORCE_RR_CPU
bool "Force round-robin CPU selection for unbound work items"
depends on DEBUG_KERNEL
default n
help
Workqueue used to implicitly guarantee that work items queued
without explicit CPU specified are put on the local CPU. This
guarantee is no longer true and while local CPU is still
preferred work items may be put on foreign CPUs. Kernel
parameter "workqueue.debug_force_rr_cpu" is added to force
round-robin CPU selection to flush out usages which depend on the
now broken guarantee. This config option enables the debug
feature by default. When enabled, memory and cache locality will
be impacted.
config DEBUG_BLOCK_EXT_DEVT
bool "Force extended block device numbers and spread them"
depends on DEBUG_KERNEL
depends on BLOCK
default n
help
BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
YOU ARE DOING. Distros, please enable this and fix whatever
is broken.
Conventionally, block device numbers are allocated from
predetermined contiguous area. However, extended block area
may introduce non-contiguous block device numbers. This
option forces most block device numbers to be allocated from
the extended space and spreads them to discover kernel or
userland code paths which assume predetermined contiguous
device number allocation.
Note that turning on this debug option shuffles all the
device numbers for all IDE and SCSI devices including libata
ones, so root partition specified using device number
directly (via rdev or root=MAJ:MIN) won't work anymore.
Textual device names (root=/dev/sdXn) will continue to work.
Say N if you are unsure.
config CPU_HOTPLUG_STATE_CONTROL
bool "Enable CPU hotplug state control"
depends on DEBUG_KERNEL
depends on HOTPLUG_CPU
default n
help
Allows to write steps between "offline" and "online" to the CPUs
sysfs target file so states can be stepped granular. This is a debug
option for now as the hotplug machinery cannot be stopped and
restarted at arbitrary points yet.
Say N if your are unsure.
config NOTIFIER_ERROR_INJECTION
tristate "Notifier error injection"
depends on DEBUG_KERNEL
select DEBUG_FS
help
This option provides the ability to inject artificial errors to
specified notifier chain callbacks. It is useful to test the error
handling of notifier call chain failures.
Say N if unsure.
config PM_NOTIFIER_ERROR_INJECT
tristate "PM notifier error injection module"
depends on PM && NOTIFIER_ERROR_INJECTION
default m if PM_DEBUG
help
This option provides the ability to inject artificial errors to
PM notifier chain callbacks. It is controlled through debugfs
interface /sys/kernel/debug/notifier-error-inject/pm
If the notifier call chain should be failed with some events
notified, write the error code to "actions/<notifier event>/error".
Example: Inject PM suspend error (-12 = -ENOMEM)
# cd /sys/kernel/debug/notifier-error-inject/pm/
# echo -12 > actions/PM_SUSPEND_PREPARE/error
# echo mem > /sys/power/state
bash: echo: write error: Cannot allocate memory
To compile this code as a module, choose M here: the module will
be called pm-notifier-error-inject.
If unsure, say N.
config OF_RECONFIG_NOTIFIER_ERROR_INJECT
tristate "OF reconfig notifier error injection module"
depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
help
This option provides the ability to inject artificial errors to
OF reconfig notifier chain callbacks. It is controlled
through debugfs interface under
/sys/kernel/debug/notifier-error-inject/OF-reconfig/
If the notifier call chain should be failed with some events
notified, write the error code to "actions/<notifier event>/error".
To compile this code as a module, choose M here: the module will
be called of-reconfig-notifier-error-inject.
If unsure, say N.
config NETDEV_NOTIFIER_ERROR_INJECT
tristate "Netdev notifier error injection module"
depends on NET && NOTIFIER_ERROR_INJECTION
help
This option provides the ability to inject artificial errors to
netdevice notifier chain callbacks. It is controlled through debugfs
interface /sys/kernel/debug/notifier-error-inject/netdev
If the notifier call chain should be failed with some events
notified, write the error code to "actions/<notifier event>/error".
Example: Inject netdevice mtu change error (-22 = -EINVAL)
# cd /sys/kernel/debug/notifier-error-inject/netdev
# echo -22 > actions/NETDEV_CHANGEMTU/error
# ip link set eth0 mtu 1024
RTNETLINK answers: Invalid argument
To compile this code as a module, choose M here: the module will
be called netdev-notifier-error-inject.
If unsure, say N.
config FUNCTION_ERROR_INJECTION
def_bool y
depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
config FAULT_INJECTION
bool "Fault-injection framework"
depends on DEBUG_KERNEL
help
Provide fault-injection framework.
For more details, see Documentation/fault-injection/.
config FAILSLAB
bool "Fault-injection capability for kmalloc"
depends on FAULT_INJECTION
depends on SLAB || SLUB
help
Provide fault-injection capability for kmalloc.
config FAIL_PAGE_ALLOC
bool "Fault-injection capabilitiy for alloc_pages()"
depends on FAULT_INJECTION
help
Provide fault-injection capability for alloc_pages().
config FAIL_MAKE_REQUEST
bool "Fault-injection capability for disk IO"
depends on FAULT_INJECTION && BLOCK
help
Provide fault-injection capability for disk IO.
config FAIL_IO_TIMEOUT
bool "Fault-injection capability for faking disk interrupts"
depends on FAULT_INJECTION && BLOCK
help
Provide fault-injection capability on end IO handling. This
will make the block layer "forget" an interrupt as configured,
thus exercising the error handling.
Only works with drivers that use the generic timeout handling,
for others it wont do anything.
config FAIL_FUTEX
bool "Fault-injection capability for futexes"
select DEBUG_FS
depends on FAULT_INJECTION && FUTEX
help
Provide fault-injection capability for futexes.
config FAULT_INJECTION_DEBUG_FS
bool "Debugfs entries for fault-injection capabilities"
depends on FAULT_INJECTION && SYSFS && DEBUG_FS
help
Enable configuration of fault-injection capabilities via debugfs.
config FAIL_FUNCTION
bool "Fault-injection capability for functions"
depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
help
Provide function-based fault-injection capability.
This will allow you to override a specific function with a return
with given return value. As a result, function caller will see
an error value and have to handle it. This is useful to test the
error handling in various subsystems.
config FAIL_MMC_REQUEST
bool "Fault-injection capability for MMC IO"
depends on FAULT_INJECTION_DEBUG_FS && MMC
help
Provide fault-injection capability for MMC IO.
This will make the mmc core return data errors. This is
useful to test the error handling in the mmc block device
and to test how the mmc host driver handles retries from
the block device.
config FAULT_INJECTION_STACKTRACE_FILTER
bool "stacktrace filter for fault-injection capabilities"
depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
depends on !X86_64
select STACKTRACE
select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
help
Provide stacktrace filter for fault-injection capabilities
config LATENCYTOP
bool "Latency measuring infrastructure"
depends on DEBUG_KERNEL
depends on STACKTRACE_SUPPORT
depends on PROC_FS
select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
select KALLSYMS
select KALLSYMS_ALL
select STACKTRACE
select SCHEDSTATS
select SCHED_DEBUG
help
Enable this option if you want to use the LatencyTOP tool
to find out which userspace is blocking on what kernel operations.
source "kernel/trace/Kconfig"
config PROVIDE_OHCI1394_DMA_INIT
bool "Remote debugging over FireWire early on boot"
depends on PCI && X86
help
If you want to debug problems which hang or crash the kernel early
on boot and the crashing machine has a FireWire port, you can use
this feature to remotely access the memory of the crashed machine
over FireWire. This employs remote DMA as part of the OHCI1394
specification which is now the standard for FireWire controllers.
With remote DMA, you can monitor the printk buffer remotely using
firescope and access all memory below 4GB using fireproxy from gdb.
Even controlling a kernel debugger is possible using remote DMA.
Usage:
If ohci1394_dma=early is used as boot parameter, it will initialize
all OHCI1394 controllers which are found in the PCI config space.
As all changes to the FireWire bus such as enabling and disabling
devices cause a bus reset and thereby disable remote DMA for all
devices, be sure to have the cable plugged and FireWire enabled on
the debugging host before booting the debug target for debugging.
This code (~1k) is freed after boot. By then, the firewire stack
in charge of the OHCI-1394 controllers should be used instead.
See Documentation/debugging-via-ohci1394.txt for more information.
config DMA_API_DEBUG
bool "Enable debugging of DMA-API usage"
select NEED_DMA_MAP_STATE
help
Enable this option to debug the use of the DMA API by device drivers.
With this option you will be able to detect common bugs in device
drivers like double-freeing of DMA mappings or freeing mappings that
were never allocated.
This also attempts to catch cases where a page owned by DMA is
accessed by the cpu in a way that could cause data corruption. For
example, this enables cow_user_page() to check that the source page is
not undergoing DMA.
This option causes a performance degradation. Use only if you want to
debug device drivers and dma interactions.
If unsure, say N.
config DMA_API_DEBUG_SG
bool "Debug DMA scatter-gather usage"
default y
depends on DMA_API_DEBUG
help
Perform extra checking that callers of dma_map_sg() have respected the
appropriate segment length/boundary limits for the given device when
preparing DMA scatterlists.
This is particularly likely to have been overlooked in cases where the
dma_map_sg() API is used for general bulk mapping of pages rather than
preparing literal scatter-gather descriptors, where there is a risk of
unexpected behaviour from DMA API implementations if the scatterlist
is technically out-of-spec.
If unsure, say N.
menuconfig RUNTIME_TESTING_MENU
bool "Runtime Testing"
def_bool y
if RUNTIME_TESTING_MENU
config LKDTM
tristate "Linux Kernel Dump Test Tool Module"
depends on DEBUG_FS
depends on BLOCK
help
This module enables testing of the different dumping mechanisms by
inducing system failures at predefined crash points.
If you don't need it: say N
Choose M here to compile this code as a module. The module will be
called lkdtm.
Documentation on how to use the module can be found in
Documentation/fault-injection/provoke-crashes.txt
config TEST_LIST_SORT
tristate "Linked list sorting test"
depends on DEBUG_KERNEL || m
help
Enable this to turn on 'list_sort()' function test. This test is
executed only once during system boot (so affects only boot time),
or at module load time.
If unsure, say N.
config TEST_SORT
tristate "Array-based sort test"
depends on DEBUG_KERNEL || m
help
This option enables the self-test function of 'sort()' at boot,
or at module load time.
If unsure, say N.
config KPROBES_SANITY_TEST
bool "Kprobes sanity tests"
depends on DEBUG_KERNEL
depends on KPROBES
help
This option provides for testing basic kprobes functionality on
boot. Samples of kprobe and kretprobe are inserted and
verified for functionality.
Say N if you are unsure.
config BACKTRACE_SELF_TEST
tristate "Self test for the backtrace code"
depends on DEBUG_KERNEL
help
This option provides a kernel module that can be used to test
the kernel stack backtrace code. This option is not useful
for distributions or general kernels, but only for kernel
developers working on architecture code.
Note that if you want to also test saved backtraces, you will
have to enable STACKTRACE as well.
Say N if you are unsure.
config RBTREE_TEST
tristate "Red-Black tree test"
depends on DEBUG_KERNEL
help
A benchmark measuring the performance of the rbtree library.
Also includes rbtree invariant checks.
config INTERVAL_TREE_TEST
tristate "Interval tree test"
depends on DEBUG_KERNEL
select INTERVAL_TREE
help
A benchmark measuring the performance of the interval tree library
config PERCPU_TEST
tristate "Per cpu operations test"
depends on m && DEBUG_KERNEL
help
Enable this option to build test module which validates per-cpu
operations.
If unsure, say N.
config ATOMIC64_SELFTEST
tristate "Perform an atomic64_t self-test"
help
Enable this option to test the atomic64_t functions at boot or
at module load time.
If unsure, say N.
config ASYNC_RAID6_TEST
tristate "Self test for hardware accelerated raid6 recovery"
depends on ASYNC_RAID6_RECOV
select ASYNC_MEMCPY
---help---
This is a one-shot self test that permutes through the
recovery of all the possible two disk failure scenarios for a
N-disk array. Recovery is performed with the asynchronous
raid6 recovery routines, and will optionally use an offload
engine if one is available.
If unsure, say N.
config TEST_HEXDUMP
tristate "Test functions located in the hexdump module at runtime"
config TEST_STRING_HELPERS
tristate "Test functions located in the string_helpers module at runtime"
config TEST_KSTRTOX
tristate "Test kstrto*() family of functions at runtime"
config TEST_PRINTF
tristate "Test printf() family of functions at runtime"
config TEST_BITMAP
tristate "Test bitmap_*() family of functions at runtime"
help
Enable this option to test the bitmap functions at boot.
If unsure, say N.
config TEST_BITFIELD
tristate "Test bitfield functions at runtime"
help
Enable this option to test the bitfield functions at boot.
If unsure, say N.
config TEST_UUID
tristate "Test functions located in the uuid module at runtime"
config TEST_XARRAY
tristate "Test the XArray code at runtime"
config TEST_OVERFLOW
tristate "Test check_*_overflow() functions at runtime"
config TEST_RHASHTABLE
tristate "Perform selftest on resizable hash table"
help
Enable this option to test the rhashtable functions at boot.
If unsure, say N.
config TEST_HASH
tristate "Perform selftest on hash functions"
help
Enable this option to test the kernel's integer (<linux/hash.h>),
string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
hash functions on boot (or module load).
This is intended to help people writing architecture-specific
optimized versions. If unsure, say N.
config TEST_IDA
tristate "Perform selftest on IDA functions"
config TEST_PARMAN
tristate "Perform selftest on priority array manager"
depends on PARMAN
help
Enable this option to test priority array manager on boot
(or module load).
If unsure, say N.
config TEST_LKM
tristate "Test module loading with 'hello world' module"
depends on m
help
This builds the "test_module" module that emits "Hello, world"
on printk when loaded. It is designed to be used for basic
evaluation of the module loading subsystem (for example when
validating module verification). It lacks any extra dependencies,
and will not normally be loaded by the system unless explicitly
requested by name.
If unsure, say N.
config TEST_USER_COPY
tristate "Test user/kernel boundary protections"
depends on m
help
This builds the "test_user_copy" module that runs sanity checks
on the copy_to/from_user infrastructure, making sure basic
user/kernel boundary testing is working. If it fails to load,
a regression has been detected in the user/kernel memory boundary
protections.
If unsure, say N.
config TEST_BPF
tristate "Test BPF filter functionality"
depends on m && NET
help
This builds the "test_bpf" module that runs various test vectors
against the BPF interpreter or BPF JIT compiler depending on the
current setting. This is in particular useful for BPF JIT compiler
development, but also to run regression tests against changes in
the interpreter code. It also enables test stubs for eBPF maps and
verifier used by user space verifier testsuite.
If unsure, say N.
config FIND_BIT_BENCHMARK
tristate "Test find_bit functions"
help
This builds the "test_find_bit" module that measure find_*_bit()
functions performance.
If unsure, say N.
config TEST_FIRMWARE
tristate "Test firmware loading via userspace interface"
depends on FW_LOADER
help
This builds the "test_firmware" module that creates a userspace
interface for testing firmware loading. This can be used to
control the triggering of firmware loading without needing an
actual firmware-using device. The contents can be rechecked by
userspace.
If unsure, say N.
config TEST_SYSCTL
tristate "sysctl test driver"
depends on PROC_SYSCTL
help
This builds the "test_sysctl" module. This driver enables to test the
proc sysctl interfaces available to drivers safely without affecting
production knobs which might alter system functionality.
If unsure, say N.
config TEST_UDELAY
tristate "udelay test driver"
help
This builds the "udelay_test" module that helps to make sure
that udelay() is working properly.
If unsure, say N.
config TEST_STATIC_KEYS
tristate "Test static keys"
depends on m
help
Test the static key interfaces.
If unsure, say N.
config TEST_KMOD
tristate "kmod stress tester"
depends on m
depends on BLOCK && (64BIT || LBDAF) # for XFS, BTRFS
depends on NETDEVICES && NET_CORE && INET # for TUN
select TEST_LKM
select XFS_FS
select TUN
select BTRFS_FS
help
Test the kernel's module loading mechanism: kmod. kmod implements
support to load modules using the Linux kernel's usermode helper.
This test provides a series of tests against kmod.
Although technically you can either build test_kmod as a module or
into the kernel we disallow building it into the kernel since
it stress tests request_module() and this will very likely cause
some issues by taking over precious threads available from other
module load requests, ultimately this could be fatal.
To run tests run:
tools/testing/selftests/kmod/kmod.sh --help
If unsure, say N.
config TEST_DEBUG_VIRTUAL
tristate "Test CONFIG_DEBUG_VIRTUAL feature"
depends on DEBUG_VIRTUAL
help
Test the kernel's ability to detect incorrect calls to
virt_to_phys() done against the non-linear part of the
kernel's virtual address map.
If unsure, say N.
config TEST_MEMCAT_P
tristate "Test memcat_p() helper function"
help
Test the memcat_p() helper for correctly merging two
pointer arrays together.
If unsure, say N.
config TEST_OBJAGG
tristate "Perform selftest on object aggreration manager"
default n
depends on OBJAGG
help
Enable this option to test object aggregation manager on boot
(or module load).
If unsure, say N.
endif # RUNTIME_TESTING_MENU
config MEMTEST
bool "Memtest"
---help---
This option adds a kernel parameter 'memtest', which allows memtest
to be set.
memtest=0, mean disabled; -- default
memtest=1, mean do 1 test pattern;
...
memtest=17, mean do 17 test patterns.
If you are unsure how to answer this question, answer N.
config BUG_ON_DATA_CORRUPTION
bool "Trigger a BUG when data corruption is detected"
select DEBUG_LIST
help
Select this option if the kernel should BUG when it encounters
data corruption in kernel memory structures when they get checked
for validity.
If unsure, say N.
source "samples/Kconfig"
source "lib/Kconfig.kgdb"
source "lib/Kconfig.ubsan"
config ARCH_HAS_DEVMEM_IS_ALLOWED
bool
config STRICT_DEVMEM
bool "Filter access to /dev/mem"
depends on MMU && DEVMEM
depends on ARCH_HAS_DEVMEM_IS_ALLOWED
default y if PPC || X86 || ARM64
---help---
If this option is disabled, you allow userspace (root) access to all
of memory, including kernel and userspace memory. Accidental
access to this is obviously disastrous, but specific access can
be used by people debugging the kernel. Note that with PAT support
enabled, even in this case there are restrictions on /dev/mem
use due to the cache aliasing requirements.
If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
file only allows userspace access to PCI space and the BIOS code and
data regions. This is sufficient for dosemu and X and all common
users of /dev/mem.
If in doubt, say Y.
config IO_STRICT_DEVMEM
bool "Filter I/O access to /dev/mem"
depends on STRICT_DEVMEM
---help---
If this option is disabled, you allow userspace (root) access to all
io-memory regardless of whether a driver is actively using that
range. Accidental access to this is obviously disastrous, but
specific access can be used by people debugging kernel drivers.
If this option is switched on, the /dev/mem file only allows
userspace access to *idle* io-memory ranges (see /proc/iomem) This
may break traditional users of /dev/mem (dosemu, legacy X, etc...)
if the driver using a given range cannot be disabled.
If in doubt, say Y.
source "arch/$(SRCARCH)/Kconfig.debug"
endmenu # Kernel hacking
|