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author | Oleg Nesterov <oleg@redhat.com> | 2013-03-22 15:04:41 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-22 16:41:20 -0700 |
commit | 2ca067efd82939dfd87827d29d36a265823a4c2f (patch) | |
tree | a6291128f65ef015ab36460a5e5f39a5bc25c4a1 /include/uapi/linux/reboot.h | |
parent | d00285884c0892bb1310df96bce6056e9ce9b9d9 (diff) | |
download | op-kernel-dev-2ca067efd82939dfd87827d29d36a265823a4c2f.zip op-kernel-dev-2ca067efd82939dfd87827d29d36a265823a4c2f.tar.gz |
poweroff: change orderly_poweroff() to use schedule_work()
David said:
Commit 6c0c0d4d1080 ("poweroff: fix bug in orderly_poweroff()")
apparently fixes one bug in orderly_poweroff(), but introduces
another. The comments on orderly_poweroff() claim it can be called
from any context - and indeed we call it from interrupt context in
arch/powerpc/platforms/pseries/ras.c for example. But since that
commit this is no longer safe, since call_usermodehelper_fns() is not
safe in interrupt context without the UMH_NO_WAIT option.
orderly_poweroff() can be used from any context but UMH_WAIT_EXEC is
sleepable. Move the "force" logic into __orderly_poweroff() and change
orderly_poweroff() to use the global poweroff_work which simply calls
__orderly_poweroff().
While at it, remove the unneeded "int argc" and change argv_split() to
use GFP_KERNEL.
We use the global "bool poweroff_force" to pass the argument, this can
obviously affect the previous request if it is pending/running. So we
only allow the "false => true" transition assuming that the pending
"true" should succeed anyway. If schedule_work() fails after that we
know that work->func() was not called yet, it must see the new value.
This means that orderly_poweroff() becomes async even if we do not run
the command and always succeeds, schedule_work() can only fail if the
work is already pending. We can export __orderly_poweroff() and change
the non-atomic callers which want the old semantics.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Feng Hong <hongfeng@marvell.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/uapi/linux/reboot.h')
0 files changed, 0 insertions, 0 deletions