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authorKirill Korotaev <dev@sw.ru>2005-05-24 19:29:47 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-24 20:08:13 -0700
commitc33880aaddbbab1ccf36f4457ed1090621f2e39a (patch)
tree2bcaa297c0688c3ce997ede15bf224c39fee6e23 /kernel/signal.c
parent6431e6a28e8df423e1ebcda065e9ff086198d2c6 (diff)
downloadlwn-c33880aaddbbab1ccf36f4457ed1090621f2e39a.tar.gz
lwn-c33880aaddbbab1ccf36f4457ed1090621f2e39a.zip
[PATCH] sigkill priority fix
If SIGKILL does not have priority, we cannot instantly kill task before it makes some unexpected job. It can be critical, but we were unable to reproduce this easily until Heiko Carstens <Heiko.Carstens@de.ibm.com> reported this problem on LKML. Signed-Off-By: Kirill Korotaev <dev@sw.ru> Signed-Off-By: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 8f3debc77c5b..b3c24c732c5a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -522,7 +522,16 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
{
int sig = 0;
- sig = next_signal(pending, mask);
+ /* SIGKILL must have priority, otherwise it is quite easy
+ * to create an unkillable process, sending sig < SIGKILL
+ * to self */
+ if (unlikely(sigismember(&pending->signal, SIGKILL))) {
+ if (!sigismember(mask, SIGKILL))
+ sig = SIGKILL;
+ }
+
+ if (likely(!sig))
+ sig = next_signal(pending, mask);
if (sig) {
if (current->notifier) {
if (sigismember(current->notifier_mask, sig)) {