Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Re: Fw: rc3-mm1: oops in keventd_stop_kthread | Date | Thu, 05 Feb 2004 16:09:29 +1100 |
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In message <20040204200410.GA3802@localhost.localdomain> you write: > On Wed, Feb 04, 2004 at 02:00:06PM +1100, Rusty Russell wrote: > > Um, why is ALSA using kthread? > > > > Is there a modprobe -r in your script somewhere? > > yes. not sure why it is called though.
Reproduced using your config, and fixed. Classic use-after-free bug: another victory for DEBUG_PAGEALLOC.
Thanks Andrey! Rusty. -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
Name: Kthread waitpid Race II Author: Rusty Russell Status: Tested on 2.6.2-rc3 Depends: Hotcpu/kthread-wait-race.patch.gz
We can't compare waitpid() result with stop->k->tgid, since the thread will be gone by then (thanks to Andrey Borzenkov and CONFIG_DEBUG_PAGEALLOC!
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.6.2-rc3-mm1/kernel/kthread.c tmp/kernel/kthread.c --- linux-2.6.2-rc3-mm1/kernel/kthread.c 2004-02-04 12:29:18.000000000 +1100 +++ tmp/kernel/kthread.c 2004-02-05 15:56:07.000000000 +1100 @@ -107,7 +112,7 @@ static void adopt_kthread(struct task_st static void keventd_stop_kthread(void *_stop) { struct kthread_stop_info *stop = _stop; - int status; + int status, pid; sigset_t blocked; struct k_sigaction sa; @@ -119,11 +124,14 @@ static void keventd_stop_kthread(void *_ allow_signal(SIGCHLD); adopt_kthread(stop->k); + /* Grab pid now: after waitpid(), stop->k is invalid. */ + pid = stop->k->tgid; + /* All signals are blocked, hence the force. */ force_sig(SIGTERM, stop->k); /* Other threads might exit: if we ask for one pid that * returns -ERESTARTSYS. */ - while (waitpid(-1, &status, __WALL) != stop->k->tgid) + while (waitpid(-1, &status, __WALL) != pid) flush_signals(current); stop->result = -((status >> 8) & 0xFF); complete(&stop->done); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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