The patch titled Subject: sysrq: use SEND_SIG_FORCED instead of force_sig() has been added to the -mm tree. Its filename is sysrq-use-send_sig_forced-instead-of-force_sig.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx> Subject: 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@xxxxxxxxxx> Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx> Cc: Alan Cox <alan@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/tty/sysrq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN drivers/tty/sysrq.c~sysrq-use-send_sig_forced-instead-of-force_sig drivers/tty/sysrq.c --- a/drivers/tty/sysrq.c~sysrq-use-send_sig_forced-instead-of-force_sig +++ a/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); } _ Subject: Subject: sysrq: use SEND_SIG_FORCED instead of force_sig() Patches currently in -mm which might be from anton.vorontsov@xxxxxxxxxx are origin.patch linux-next.patch sysrq-use-send_sig_forced-instead-of-force_sig.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html