path: root/ipc/ipc_sysctl.c
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authorManfred Spraul <manfred@colorfullife.com>2008-07-25 01:48:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 10:53:42 -0700
commit380af1b33b3ff92df5cda96329b58f5d1b6b5a53 (patch)
tree9a47d66c18e4aae2093a708a7509c0f188ee0bd1 /ipc/ipc_sysctl.c
parenta1193f8ec091cd8fd309cc2982abe4499f6f2b4d (diff)
ipc/sem.c: rewrite undo list locking
The attached patch: - reverses the locking order of ulp->lock and sem_lock: Previously, it was first ulp->lock, then inside sem_lock. Now it's the other way around. - converts the undo structure to rcu. Benefits: - With the old locking order, IPC_RMID could not kfree the undo structures. The stale entries remained in the linked lists and were released later. - The patch fixes a a race in semtimedop(): if both IPC_RMID and a semget() that recreates exactly the same id happen between find_alloc_undo() and sem_lock, then semtimedop() would access already kfree'd memory. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Reviewed-by: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc/ipc_sysctl.c')
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