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author | Linus Torvalds <torvalds@g5.osdl.org> | 2006-11-04 13:03:00 -0800 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-11-04 13:03:00 -0800 |
commit | 10b1fbdb0a0ca91847a534ad26d0bc250c25b74f (patch) | |
tree | 67a3e6d7069e9281b0f5819f4acf91d7150a5d74 /arch | |
parent | 45c18b0bb579b5c1b89f8c99f1b6ffa4c586ba08 (diff) |
Make sure "user->sigpending" count is in sync
The previous commit (45c18b0bb579b5c1b89f8c99f1b6ffa4c586ba08, aka "Fix
unlikely (but possible) race condition on task->user access") fixed a
potential oops due to __sigqueue_alloc() getting its "user" pointer out
of sync with switch_user(), and accessing a user pointer that had been
de-allocated on another CPU.
It still left another (much less serious) problem, where a concurrent
__sigqueue_alloc and swich_user could cause sigqueue_alloc to do signal
pending reference counting for a _different_ user than the one it then
actually ended up using. No oops, but we'd end up with the wrong signal
accounting.
Another case of Oleg's eagle-eyes picking up the problem.
This is trivially fixed by just making sure we load whichever "user"
structure we decide to use (it doesn't matter _which_ one we pick, we
just need to pick one) just once.
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
0 files changed, 0 insertions, 0 deletions