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authorOleg Nesterov <oleg@redhat.com>2013-08-09 17:19:13 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2013-08-09 10:48:20 -0700
commit201d3dfa4da10ac45b260320b94e2f2f0e10d687 (patch)
tree6b6db774cee8a33d070fdae0b77b3594cd4640cf
parent6c2580c501c660fdfb506061e016d84570fceba1 (diff)
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dlm: kill the unnecessary and wrong device_close()->recalc_sigpending()
device_close()->recalc_sigpending() is not needed, sigprocmask() takes care of TIF_SIGPENDING correctly. And without ->siglock it is racy and wrong, it can wrongly clear TIF_SIGPENDING and miss a signal. But even with this patch device_close() is still buggy: 1. sigprocmask() should not be used, we have set_task_blocked(), but this is minor. 2. We should never block SIGKILL or SIGSTOP, and this is what the code tries to do. 3. This can't protect against SIGKILL or SIGSTOP anyway. Another thread can do signal_wake_up(), say, do_signal_stop() or complete_signal() or debugger. 4. sigprocmask(SIG_BLOCK, allsigs) doesn't necessarily clears TIF_SIGPENDING, say, freezing() or ->jobctl. 5. device_write() looks equally wrong by the same reason. Looks like, this tries to protect some wait_event_interruptible() logic from signals, it should be turned into uninterruptible wait. Or we need to implement something like signals_stop/start for such a use-case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/dlm/user.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 911649a..8121491 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -686,7 +686,6 @@ static int device_close(struct inode *inode, struct file *file)
device_remove_lockspace() */
sigprocmask(SIG_SETMASK, &tmpsig, NULL);
- recalc_sigpending();
return 0;
}