Revision abd96ecb298675a21c412a29f5de2f80174d5f18 authored by Oleg Nesterov on 22 August 2007, 21:01:58 UTC, committed by Linus Torvalds on 23 August 2007, 02:52:47 UTC
de_thread: if (atomic_read(&oldsighand->count) <= 1) BUG_ON(atomic_read(&sig->count) != 1); This is not safe without the rmb() in between. The results of two correctly ordered __exit_signal()->atomic_dec_and_test()'s could be seen out of order on our CPU. The same is true for the "thread_group_empty()" case, __unhash_process()'s changes could be seen before atomic_dec_and_test(&sig->count). On some platforms (including i386) atomic_read() doesn't provide even the compiler barrier, in that case these checks are simply racy. Remove these BUG_ON()'s. Alternatively, we can do something like BUG_ON( ({ smp_rmb(); atomic_read(&sig->count) != 1; }) ); Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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File | Mode | Size |
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.gitignore | -rw-r--r-- | 34 bytes |
Makefile | -rw-r--r-- | 475 bytes |
empty.c | -rw-r--r-- | 54 bytes |
file2alias.c | -rw-r--r-- | 19.2 KB |
mk_elfconfig.c | -rw-r--r-- | 1.5 KB |
modpost.c | -rw-r--r-- | 42.9 KB |
modpost.h | -rw-r--r-- | 3.6 KB |
sumversion.c | -rw-r--r-- | 11.4 KB |
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