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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-02-04 22:27:24 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-05 09:44:07 -0800 |
| commit | ed5d2cac114202fe2978a9cbcab8f5032796d538 (patch) | |
| tree | aa9aaea1aa0945bd9159685d1b04897d105a90c9 /include | |
| parent | f558b7e408026eb3c6afcd0e8fc1f7fe31195a6a (diff) | |
| download | linux-ed5d2cac114202fe2978a9cbcab8f5032796d538.tar.gz linux-ed5d2cac114202fe2978a9cbcab8f5032796d538.tar.bz2 linux-ed5d2cac114202fe2978a9cbcab8f5032796d538.zip | |
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 'include')
| -rw-r--r-- | include/linux/sched.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 680bb03a4b90..483ea4e1accf 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -555,6 +555,13 @@ struct signal_struct { #define SIGNAL_STOP_CONTINUED 0x00000004 /* SIGCONT since WCONTINUED reap */ #define SIGNAL_GROUP_EXIT 0x00000008 /* group exit in progress */ +/* If true, all threads except ->group_exit_task have pending SIGKILL */ +static inline int signal_group_exit(const struct signal_struct *sig) +{ + return (sig->flags & SIGNAL_GROUP_EXIT) || + (sig->group_exit_task != NULL); +} + /* * Some day this will be a full-fledged user tracking system.. */ |