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authorOleg Nesterov <oleg@tv-sign.ru>2007-08-22 17:01:48 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-08-22 22:52:46 -0400
commitf9ee228bdc82cff8ea1ec00fd952890e00679dd8 (patch)
tree4c087502431a70bf7479555dcf4c1c4265835ebe
parent834d216e1f804560bd1421c511ad168d7c24b01d (diff)
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 ce62f7b65f17..af4361c927a9 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -780,18 +780,12 @@ static int de_thread(struct task_struct *tsk)
780 int count; 780 int count;
781 781
782 /* 782 /*
783 * Tell all the sighand listeners that this sighand has
784 * been detached. The signalfd_detach() function grabs the
785 * sighand lock, if signal listeners are present on the sighand.
786 */
787 signalfd_detach(tsk);
788
789 /*
790 * If we don't share sighandlers, then we aren't sharing anything 783 * If we don't share sighandlers, then we aren't sharing anything
791 * and we can just re-use it all. 784 * and we can just re-use it all.
792 */ 785 */
793 if (atomic_read(&oldsighand->count) <= 1) { 786 if (atomic_read(&oldsighand->count) <= 1) {
794 BUG_ON(atomic_read(&sig->count) != 1); 787 BUG_ON(atomic_read(&sig->count) != 1);
788 signalfd_detach(tsk);
795 exit_itimers(sig); 789 exit_itimers(sig);
796 return 0; 790 return 0;
797 } 791 }
@@ -930,6 +924,7 @@ static int de_thread(struct task_struct *tsk)
930 sig->flags = 0; 924 sig->flags = 0;
931 925
932no_thread_group: 926no_thread_group:
927 signalfd_detach(tsk);
933 exit_itimers(sig); 928 exit_itimers(sig);
934 if (leader) 929 if (leader)
935 release_task(leader); 930 release_task(leader);
diff --git a/fs/signalfd.c b/fs/signalfd.c
index 7b941abbcde0..a8e293d30034 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)
56 sighand = lock_task_sighand(lk->tsk, &lk->flags); 56 sighand = lock_task_sighand(lk->tsk, &lk->flags);
57 rcu_read_unlock(); 57 rcu_read_unlock();
58 58
59 if (sighand && !ctx->tsk) { 59 if (!sighand)
60 return 0;
61
62 if (!ctx->tsk) {
60 unlock_task_sighand(lk->tsk, &lk->flags); 63 unlock_task_sighand(lk->tsk, &lk->flags);
61 sighand = NULL; 64 return 0;
62 } 65 }
63 66
64 return sighand != NULL; 67 if (lk->tsk->tgid == current->tgid)
68 lk->tsk = current;
69
70 return 1;
65} 71}
66 72
67static void signalfd_unlock(struct signalfd_lockctx *lk) 73static 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
331 337
332 init_waitqueue_head(&ctx->wqh); 338 init_waitqueue_head(&ctx->wqh);
333 ctx->sigmask = sigmask; 339 ctx->sigmask = sigmask;
334 ctx->tsk = current; 340 ctx->tsk = current->group_leader;
335 341
336 sighand = current->sighand; 342 sighand = current->sighand;
337 /* 343 /*