]> git.baikalelectronics.ru Git - kernel.git/commit
kernel/watchdog: use nmi registers snapshot in hardlockup handler
authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Wed, 14 Dec 2016 23:04:04 +0000 (15:04 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 15 Dec 2016 00:04:07 +0000 (16:04 -0800)
commit50532333ba9f0d664833857f452fc3e5d608b74b
tree3594461f9a790f7da4b8785f9cbf3e6b0f14d14d
parent1831c69d66310d3553b147bfda30baf7b253e0cb
kernel/watchdog: use nmi registers snapshot in hardlockup handler

NMI handler doesn't call set_irq_regs(), it's set only by normal IRQ.
Thus get_irq_regs() returns NULL or stale registers snapshot with IP/SP
pointing to the code interrupted by IRQ which was interrupted by NMI.
NULL isn't a problem: in this case watchdog calls dump_stack() and
prints full stack trace including NMI.  But if we're stuck in IRQ
handler then NMI watchlog will print stack trace without IRQ part at
all.

This patch uses registers snapshot passed into NMI handler as arguments:
these registers point exactly to the instruction interrupted by NMI.

Fixes: 9694272db3af ("kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup")
Link: http://lkml.kernel.org/r/146771764784.86724.6006627197118544150.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: <stable@vger.kernel.org> [4.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/watchdog.c