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authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-04-05 23:25:05 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2012-04-06 00:25:50 +0200
commitb82c32872db20667d6ee8e2ea1e7bdec791bdcc7 (patch)
tree6677f42c6bc4f6efb07c862c558840c1114610fc
parentproc: fix mount -t proc -o AAA (diff)
downloadlinux-b82c32872db20667d6ee8e2ea1e7bdec791bdcc7.tar.xz
linux-b82c32872db20667d6ee8e2ea1e7bdec791bdcc7.zip
sysrq: use SEND_SIG_FORCED instead of force_sig()
Change send_sig_all() to use do_send_sig_info(SEND_SIG_FORCED) instead of force_sig(SIGKILL). With the recent changes we do not need force_ to kill the CLONE_NEWPID tasks. And this is more correct. force_sig() can race with the exiting thread, while do_send_sig_info(group => true) kill the whole process. Some more notes from Oleg Nesterov: > Just one note. This change makes no difference for sysrq_handle_kill(). > But it obviously changes the behaviour sysrq_handle_term(). I think > this is fine, if you want to really kill the task which blocks/ignores > SIGTERM you can use sysrq_handle_kill(). > > Even ignoring the reasons why force_sig() is simply wrong here, > force_sig(SIGTERM) looks strange. The task won't be killed if it has > a handler, but SIG_IGN can't help. However if it has the handler > but blocks SIGTERM temporary (this is very common) it will be killed. Also, > force_sig() can't kill the process if the main thread has already > exited. IOW, it is trivial to create the process which can't be > killed by sysrq. So, this patch fixes the issue. Suggested-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Cc: Alan Cox <alan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/tty/sysrq.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 136e86faa1e1..05728894a88c 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -327,7 +327,7 @@ static void send_sig_all(int sig)
if (is_global_init(p))
continue;
- force_sig(sig, p);
+ do_send_sig_info(sig, SEND_SIG_FORCED, p, true);
}
read_unlock(&tasklist_lock);
}