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authorArjan van de Ven <arjan@linux.intel.com>2007-12-20 09:01:17 -0500
committerIngo Molnar <mingo@elte.hu>2007-12-20 09:01:17 -0500
commit2c3b20e91fe3a083c5d9bc79437c485866ea251c (patch)
tree6d2b9e00efc89452863e71a8712398aeee3eccdd /kernel
parent67e2be02328b9a61a9c799fbdd4ec94d7da0c323 (diff)
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.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/panic.c b/kernel/panic.c
index 6f6e03e91595..da4d6bac270e 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -19,6 +19,7 @@
19#include <linux/nmi.h> 19#include <linux/nmi.h>
20#include <linux/kexec.h> 20#include <linux/kexec.h>
21#include <linux/debug_locks.h> 21#include <linux/debug_locks.h>
22#include <linux/random.h>
22 23
23int panic_on_oops; 24int panic_on_oops;
24int tainted; 25int tainted;
@@ -266,12 +267,29 @@ void oops_enter(void)
266} 267}
267 268
268/* 269/*
270 * 64-bit random ID for oopses:
271 */
272static u64 oops_id;
273
274static int init_oops_id(void)
275{
276 if (!oops_id)
277 get_random_bytes(&oops_id, sizeof(oops_id));
278
279 return 0;
280}
281late_initcall(init_oops_id);
282
283/*
269 * Called when the architecture exits its oops handler, after printing 284 * Called when the architecture exits its oops handler, after printing
270 * everything. 285 * everything.
271 */ 286 */
272void oops_exit(void) 287void oops_exit(void)
273{ 288{
274 do_oops_enter_exit(); 289 do_oops_enter_exit();
290 init_oops_id();
291 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
292 (unsigned long long)oops_id);
275} 293}
276 294
277#ifdef CONFIG_CC_STACKPROTECTOR 295#ifdef CONFIG_CC_STACKPROTECTOR