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author | Arjan van de Ven <arjan@linux.intel.com> | 2007-12-20 14:01:17 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2007-12-20 14:01:17 (GMT) |
commit | 2c3b20e91fe3a083c5d9bc79437c485866ea251c (patch) | |
tree | 6d2b9e00efc89452863e71a8712398aeee3eccdd /kernel | |
parent | 67e2be02328b9a61a9c799fbdd4ec94d7da0c323 (diff) | |
download | linux-fsl-qoriq-2c3b20e91fe3a083c5d9bc79437c485866ea251c.tar.xz |
debug: add end-of-oops marker
Right now it's nearly impossible for parsers that collect kernel crashes
from logs or emails (such as www.kerneloops.org) to detect the
end-of-oops condition. In addition, it's not currently possible to
detect whether or not 2 oopses that look alike are actually the same
oops reported twice, or are truly two unique oopses.
This patch adds an end-of-oops marker, and makes the end marker include
a very simple 64-bit random ID to be able to detect duplicate reports.
Normally, this ID is calculated as a late_initcall() (in the hope that
at that time there is enough entropy to get a unique enough ID); however
for early oopses the oops_exit() function needs to generate the ID on
the fly.
We do this all at the _end_ of an oops printout, so this does not impact
our ability to get the most important portions of a crash out to the
console first.
[ Sidenote: the already existing oopses-since-bootup counter we print
during crashes serves as the differentiator between multiple oopses
that trigger during the same bootup. ]
Tested on 32-bit and 64-bit x86. Artificially injected very early
crashes as well, as expected they result in this constant ID after
multiple bootups:
---[ end trace ca143223eefdc828 ]---
---[ end trace ca143223eefdc828 ]---
because the random pools are still all zero. But it all still works
fine and causes no additional problems (which is the main goal of
instrumentation code).
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/panic.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/panic.c b/kernel/panic.c index 6f6e03e..da4d6ba 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -19,6 +19,7 @@ #include <linux/nmi.h> #include <linux/kexec.h> #include <linux/debug_locks.h> +#include <linux/random.h> int panic_on_oops; int tainted; @@ -266,12 +267,29 @@ void oops_enter(void) } /* + * 64-bit random ID for oopses: + */ +static u64 oops_id; + +static int init_oops_id(void) +{ + if (!oops_id) + get_random_bytes(&oops_id, sizeof(oops_id)); + + return 0; +} +late_initcall(init_oops_id); + +/* * Called when the architecture exits its oops handler, after printing * everything. */ void oops_exit(void) { do_oops_enter_exit(); + init_oops_id(); + printk(KERN_WARNING "---[ end trace %016llx ]---\n", + (unsigned long long)oops_id); } #ifdef CONFIG_CC_STACKPROTECTOR |