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authorOleg Nesterov <oleg@tv-sign.ru>2008-02-04 22:27:24 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 09:44:07 -0800
commited5d2cac114202fe2978a9cbcab8f5032796d538 (patch)
treeaa9aaea1aa0945bd9159685d1b04897d105a90c9 /kernel/exit.c
parentf558b7e408026eb3c6afcd0e8fc1f7fe31195a6a (diff)
downloadlinux-ed5d2cac114202fe2978a9cbcab8f5032796d538.tar.gz
exec: rework the group exit and fix the race with kill
As Roland pointed out, we have the very old problem with exec. de_thread() sets SIGNAL_GROUP_EXIT, kills other threads, changes ->group_leader and then clears signal->flags. All signals (even fatal ones) sent in this window (which is not too small) will be lost. With this patch exec doesn't abuse SIGNAL_GROUP_EXIT. signal_group_exit(), the new helper, should be used to detect exit_group() or exec() in progress. It can have more users, but this patch does only strictly necessary changes. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Robin Holt <holt@sgi.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>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 9e459fefda7..9d3d0f0b27d 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1083,11 +1083,12 @@ do_group_exit(int exit_code)
struct signal_struct *const sig = current->signal;
struct sighand_struct *const sighand = current->sighand;
spin_lock_irq(&sighand->siglock);
- if (sig->flags & SIGNAL_GROUP_EXIT)
+ if (signal_group_exit(sig))
/* Another thread got here before we took the lock. */
exit_code = sig->group_exit_code;
else {
sig->group_exit_code = exit_code;
+ sig->flags = SIGNAL_GROUP_EXIT;
zap_other_threads(current);
}
spin_unlock_irq(&sighand->siglock);