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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 /include
parentf558b7e408026eb3c6afcd0e8fc1f7fe31195a6a (diff)
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.h7
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..
*/