Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=198466b41d11dd062fb26ee0376080458d7bfcaf
Commit: 198466b41d11dd062fb26ee0376080458d7bfcaf
Parent: bdff746a3915f109bd13730b6847e33e17e91ed3
Author: Oleg Nesterov <[EMAIL PROTECTED]>
AuthorDate: Mon Feb 4 22:27:23 2008 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue Feb 5 09:44:07 2008 -0800
__group_complete_signal(): fix coredump with group stop race
When __group_complete_signal() sees sig_kernel_coredump() signal, it starts
the group stop, but sets ->group_exit_task = t in a hope that "t" will
actually dequeue this signal and invoke do_coredump(). However, by the
time "t" enters get_signal_to_deliver() it is possible that the signal was
blocked/ignored or we have another pending !SIG_KERNEL_COREDUMP_MASK signal
which will be dequeued first. This means the task could be stopped but not
killed.
Remove this code from __group_complete_signal(). Note also this patch
removes the bogus signal_wake_up(t, 1). This thread can't be
STOPPED/TRACED, note the corresponding check in wants_signal().
Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>
Cc: Davide Libenzi <[EMAIL PROTECTED]>
Cc: Ingo Molnar <[EMAIL PROTECTED]>
Cc: Robin Holt <[EMAIL PROTECTED]>
Cc: Roland McGrath <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
kernel/signal.c | 30 ------------------------------
1 files changed, 0 insertions(+), 30 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index 4333b6d..ea90c34 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -911,27 +911,6 @@ __group_complete_signal(int sig, struct task_struct *p)
} while_each_thread(p, t);
return;
}
-
- /*
- * There will be a core dump. We make all threads other
- * than the chosen one go into a group stop so that nothing
- * happens until it gets scheduled, takes the signal off
- * the shared queue, and does the core dump. This is a
- * little more complicated than strictly necessary, but it
- * keeps the signal state that winds up in the core dump
- * unchanged from the death state, e.g. which thread had
- * the core-dump signal unblocked.
- */
- rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
- rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
- p->signal->group_stop_count = 0;
- p->signal->group_exit_task = t;
- p = t;
- do {
- p->signal->group_stop_count++;
- signal_wake_up(t, t == p);
- } while_each_thread(p, t);
- return;
}
/*
@@ -1762,15 +1741,6 @@ static int handle_group_stop(void)
{
int stop_count;
- if (current->signal->group_exit_task == current) {
- /*
- * Group stop is so we can do a core dump,
- * We are the initiating thread, so get on with it.
- */
- current->signal->group_exit_task = NULL;
- return 0;
- }
-
if (current->signal->flags & SIGNAL_GROUP_EXIT)
/*
* Group stop is so another thread can do a core dump,
-
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