From: Arjan van de Ven Date: Mon, 10 Jul 2006 11:45:42 +0000 (-0700) Subject: [PATCH] lockdep: disable lock debugging when kernel state becomes untrusted X-Git-Tag: v2.6.18-rc2~128 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2c16e9c888985761511bd1905b00fb271169c3c0;p=linux-2.6 [PATCH] lockdep: disable lock debugging when kernel state becomes untrusted Disable lockdep debugging in two situations where the integrity of the kernel no longer is guaranteed: when oopsing and when hitting a tainting-condition. The goal is to not get weird lockdep traces that don't make sense or are otherwise undebuggable, to not waste time. Lockdep assumes that the previous state it knows about is valid to operate, which is why lockdep turns itself off after the first violation it reports, after that point it can no longer make that assumption. A kernel oops means that the integrity of the kernel compromised; in addition anything lockdep would report is of lesser importance than the oops. All the tainting conditions are of similar integrity-violating nature and also make debugging/diagnosing more difficult. Signed-off-by: Arjan van de Ven Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/panic.c b/kernel/panic.c index ab13f0f668..d8a0bca212 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -172,6 +172,7 @@ const char *print_tainted(void) void add_taint(unsigned flag) { + debug_locks_off(); /* can't trust the integrity of the kernel anymore */ tainted |= flag; } EXPORT_SYMBOL(add_taint); @@ -256,6 +257,7 @@ int oops_may_print(void) */ void oops_enter(void) { + debug_locks_off(); /* can't trust the integrity of the kernel anymore */ do_oops_enter_exit(); }