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authorOleg Nesterov <oleg@tv-sign.ru>2007-08-22 14:01:48 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-08-22 19:52:46 -0700
commitf9ee228bdc82cff8ea1ec00fd952890e00679dd8 (patch)
tree4c087502431a70bf7479555dcf4c1c4265835ebe
parent834d216e1f804560bd1421c511ad168d7c24b01d (diff)
downloadlinux-2.6.34-ux500-f9ee228bdc82cff8ea1ec00fd952890e00679dd8.tar.gz
signalfd: make it group-wide, fix posix-timers scheduling
With this patch any thread can dequeue its own private signals via signalfd, even if it was created by another sub-thread. To do so, we pass "current" to dequeue_signal() if the caller is from the same thread group. This also fixes the scheduling of posix timers broken by the previous patch. If the caller doesn't belong to this thread group, we can't handle __SI_TIMER case properly anyway. Perhaps we should forbid the cross-process signalfd usage and convert ctx->tsk to ctx->sighand. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Roland McGrath <roland@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/exec.c9
-rw-r--r--fs/signalfd.c14
2 files changed, 12 insertions, 11 deletions
diff --git a/fs/exec.c b/fs/exec.c
index ce62f7b65f1..af4361c927a 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -780,18 +780,12 @@ static int de_thread(struct task_struct *tsk)
int count;
/*
- * Tell all the sighand listeners that this sighand has
- * been detached. The signalfd_detach() function grabs the
- * sighand lock, if signal listeners are present on the sighand.
- */
- signalfd_detach(tsk);
-
- /*
* If we don't share sighandlers, then we aren't sharing anything
* and we can just re-use it all.
*/
if (atomic_read(&oldsighand->count) <= 1) {
BUG_ON(atomic_read(&sig->count) != 1);
+ signalfd_detach(tsk);
exit_itimers(sig);
return 0;
}
@@ -930,6 +924,7 @@ static int de_thread(struct task_struct *tsk)
sig->flags = 0;
no_thread_group:
+ signalfd_detach(tsk);
exit_itimers(sig);
if (leader)
release_task(leader);
diff --git a/fs/signalfd.c b/fs/signalfd.c
index 7b941abbcde..a8e293d3003 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -56,12 +56,18 @@ static int signalfd_lock(struct signalfd_ctx *ctx, struct signalfd_lockctx *lk)
sighand = lock_task_sighand(lk->tsk, &lk->flags);
rcu_read_unlock();
- if (sighand && !ctx->tsk) {
+ if (!sighand)
+ return 0;
+
+ if (!ctx->tsk) {
unlock_task_sighand(lk->tsk, &lk->flags);
- sighand = NULL;
+ return 0;
}
- return sighand != NULL;
+ if (lk->tsk->tgid == current->tgid)
+ lk->tsk = current;
+
+ return 1;
}
static void signalfd_unlock(struct signalfd_lockctx *lk)
@@ -331,7 +337,7 @@ asmlinkage long sys_signalfd(int ufd, sigset_t __user *user_mask, size_t sizemas
init_waitqueue_head(&ctx->wqh);
ctx->sigmask = sigmask;
- ctx->tsk = current;
+ ctx->tsk = current->group_leader;
sighand = current->sighand;
/*