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, - To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html