userfaultfd: disable irqs when taking the waitqueue lock
authorChristoph Hellwig <hch@lst.de>
Fri, 26 Oct 2018 22:02:19 +0000 (15:02 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 26 Oct 2018 23:25:18 +0000 (16:25 -0700)
commitae62c16e105a869524afcf8a07ee85c5ae5d0479
treef91def5f8e72340a5ebafa664fe296c965a96b9a
parentfa76da461bb0be13c8339d984dcf179151167c8f
userfaultfd: disable irqs when taking the waitqueue lock

userfaultfd contains howe-grown locking of the waitqueue lock, and does
not disable interrupts.  This relies on the fact that no one else takes it
from interrupt context and violates an invariat of the normal waitqueue
locking scheme.  With aio poll it is easy to trigger other locks that
disable interrupts (or are called from interrupt context).

Link: http://lkml.kernel.org/r/20181018154101.18750-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org> [4.19.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/userfaultfd.c