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author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-06-02 18:53:37 (GMT) |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-06-09 06:43:04 (GMT) |
commit | b46b6942b39e577fe3ef1af928cd927864011247 (patch) | |
tree | 8eea7316ac79fae34ee7fdbccc580fbac1589ff3 /arch/powerpc/mm/numa.c | |
parent | 3035c8634f0538a0c6946e3191bb6c9284b63798 (diff) | |
download | linux-fsl-qoriq-b46b6942b39e577fe3ef1af928cd927864011247.tar.xz |
powerpc/mm: Fix a AB->BA deadlock scenario with nohash MMU context lock
The MMU context_lock can be taken from switch_mm() while the
rq->lock is held. The rq->lock can also be taken from interrupts,
thus if we get interrupted in destroy_context() with the context
lock held and that interrupt tries to take the rq->lock, there's
a possible deadlock scenario with another CPU having the rq->lock
and calling switch_mm() which takes our context lock.
The fix is to always ensure interrupts are off when taking our
context lock. The switch_mm() path is already good so this fixes
the destroy_context() path.
While at it, turn the context lock into a new style spinlock.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/mm/numa.c')
0 files changed, 0 insertions, 0 deletions