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Taint kernel after WARN_ON(condition)

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The kernel is sent to tainted within the warn_on_slowpath() function, and
whenever a warning occurs the new taint flag 'W' is set.  This is useful to
know if a warning occurred before a BUG by preserving the warning as a flag
in the taint state.

This does not work on architectures where WARN_ON has its own definition.
These archs are:
	1. s390
	2. superh
	3. avr32
	4. parisc

The maintainers of these architectures have been added in the Cc: list
in this email to alert them to the situation.

The documentation in oops-tracing.txt has been updated to include the
new flag.

Signed-off-by: Nur Hussein <nurhussein@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nur Hussein 2008-04-29 00:58:39 -07:00 committed by Linus Torvalds
parent bd3feb13e1
commit 95b570c9ce
3 changed files with 11 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/oops-tracing.txt
View File

@ -253,6 +253,10 @@ characters, each representing a particular tainted value.
8: 'D' if the kernel has died recently, i.e. there was an OOPS or BUG.
9: 'A' if the ACPI table has been overridden.
10: 'W' if a warning has previously been issued by the kernel.
The primary reason for the 'Tainted: ' string is to tell kernel
debuggers if this is a clean kernel or if anything unusual has
occurred. Tainting is permanent: even if an offending module is

1
include/linux/kernel.h
View File

@ -255,6 +255,7 @@ extern enum system_states {
#define TAINT_USER (1<<6)
#define TAINT_DIE (1<<7)
#define TAINT_OVERRIDDEN_ACPI_TABLE (1<<8)
#define TAINT_WARN (1<<9)
extern void dump_stack(void) __cold;

8
kernel/panic.c
View File

@ -153,6 +153,8 @@ EXPORT_SYMBOL(panic);
* 'M' - System experienced a machine check exception.
* 'B' - System has hit bad_page.
* 'U' - Userspace-defined naughtiness.
* 'A' - ACPI table overridden.
* 'W' - Taint on warning.
*
* The string is overwritten by the next call to print_taint().
*/
@ -161,7 +163,7 @@ const char *print_tainted(void)
{
static char buf[20];
if (tainted) {
snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c%c",
snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c%c%c",
tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
@ -170,7 +172,8 @@ const char *print_tainted(void)
tainted & TAINT_BAD_PAGE ? 'B' : ' ',
tainted & TAINT_USER ? 'U' : ' ',
tainted & TAINT_DIE ? 'D' : ' ',
tainted & TAINT_OVERRIDDEN_ACPI_TABLE ? 'A' : ' ');
tainted & TAINT_OVERRIDDEN_ACPI_TABLE ? 'A' : ' ',
tainted & TAINT_WARN ? 'W' : ' ');
}
else
snprintf(buf, sizeof(buf), "Not tainted");
@ -312,6 +315,7 @@ void warn_on_slowpath(const char *file, int line)
print_modules();
dump_stack();
print_oops_end_marker();
add_taint(TAINT_WARN);
}
EXPORT_SYMBOL(warn_on_slowpath);
#endif