]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
change kernel threads to ignore signals instead of blocking them
authorOleg Nesterov <oleg@tv-sign.ru>
Wed, 9 May 2007 09:34:37 +0000 (02:34 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 9 May 2007 19:30:53 +0000 (12:30 -0700)
commit10ab825bdef8df510f99c703a5a2d9b13a4e31a5
treee4db81f26c03ba5a5bff43ed44646a4ed4509d67
parent5de18d169739293e27e0cf9acfc75a2d2f4aa572
change kernel threads to ignore signals instead of blocking them

Currently kernel threads use sigprocmask(SIG_BLOCK) to protect against
signals.  This doesn't prevent the signal delivery, this only blocks
signal_wake_up().  Every "killall -33 kthreadd" means a "struct siginfo"
leak.

Change kthreadd_setup() to set all handlers to SIG_IGN instead of blocking
them (make a new helper ignore_signals() for that).  If the kernel thread
needs some signal, it should use allow_signal() anyway, and in that case it
should not use CLONE_SIGHAND.

Note that we can't change daemonize() (should die!) in the same way,
because it can be used along with CLONE_SIGHAND.  This means that
allow_signal() still should unblock the signal to work correctly with
daemonize()ed threads.

However, disallow_signal() doesn't block the signal any longer but ignores
it.

NOTE: with or without this patch the kernel threads are not protected from
handle_stop_signal(), this seems harmless, but not good.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/sched.h
kernel/exit.c
kernel/kthread.c
kernel/signal.c