From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [x86] BUG: unable to handle kernel paging request at 00740060
Date: Tue, 8 Oct 2013 16:34:00 +0200 [thread overview]
Message-ID: <20131008143400.GA14721@redhat.com> (raw)
In-Reply-To: <CA+55aFxEeKixnH7mZZs5iwupA9_GsRN0N7QZxqcTcE4RKZvTTg@mail.gmail.com>
I'll try to find other messages to understand what you are talking
about, just one note for now....
On 10/07, Linus Torvalds wrote:
>
> Your oops makes very little sense, it looks like task_work_run() just
> called out to random crap, probably because the work was already
> released, so "work->func()" ends up being bad.
Or task_work_run() can hit work->func == NULL if do_exit() is called
twice if, say, the task does BUG() after exit_task_work().
> participants anyway, just in case there is some race. The comment says
> that it can race with task_work_cancel() playing with *work. Oleg,
> comments?
The comment tries to say that if we are racing with task_work_cancel()
it can't delete the first entry == work, we won the race, its
cmpxchg(task->task_works) should fail.
Howver, task_work_cancel() can delete one of the next entries and
change, say, work->next. And we need to wait anyway if it scans this
list.
I'll try to recheck, but so far I do not see anything wrong.
Oleg.
next prev parent reply other threads:[~2013-10-08 14:41 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-05 23:44 [x86] BUG: unable to handle kernel paging request at 00740060 Fengguang Wu
2013-10-05 23:47 ` [x86] BUG: unable to handle kernel paging request at 08000060 Fengguang Wu
2013-10-06 7:27 ` Mike Galbraith
2013-10-06 7:36 ` Fengguang Wu
2013-10-07 8:49 ` Peter Zijlstra
2013-10-07 9:17 ` Fengguang Wu
2013-10-07 9:36 ` Peter Zijlstra
2013-10-07 9:46 ` Fengguang Wu
2013-10-07 8:55 ` [x86] BUG: unable to handle kernel paging request at 00740060 Peter Zijlstra
2013-10-07 9:08 ` Peter Zijlstra
2013-10-07 11:32 ` Fengguang Wu
2013-10-07 9:27 ` Fengguang Wu
2013-10-07 18:47 ` Linus Torvalds
2013-10-08 7:51 ` Fengguang Wu
2013-10-08 16:21 ` Linus Torvalds
2013-10-08 17:15 ` [x86] BUG: unable to handle kernel NULL pointer dereference at (null) Fengguang Wu
2013-10-08 17:31 ` Linus Torvalds
2013-10-09 1:09 ` Fengguang Wu
2013-10-09 1:33 ` Linus Torvalds
2013-10-08 18:51 ` [x86] BUG: unable to handle kernel paging request at 00740060 Oleg Nesterov
2013-10-08 19:05 ` Jakub Jelinek
2013-10-08 19:20 ` Linus Torvalds
2013-10-08 19:34 ` Linus Torvalds
2013-10-08 19:35 ` Oleg Nesterov
2013-10-08 19:49 ` Linus Torvalds
2013-10-09 1:43 ` Mike Galbraith
2013-10-08 19:05 ` Linus Torvalds
2013-10-08 16:46 ` Oleg Nesterov
2013-10-08 14:34 ` Oleg Nesterov [this message]
2013-10-09 8:04 ` Fengguang Wu
2013-10-09 12:19 ` Fengguang Wu
2013-10-09 12:21 ` Fengguang Wu
2013-10-09 12:27 ` Peter Zijlstra
2013-10-09 12:52 ` Ingo Molnar
2013-10-09 17:18 ` Ingo Molnar
2013-10-10 2:15 ` Mike Galbraith
2013-10-09 12:56 ` Fengguang Wu
2013-10-09 12:43 ` Oleg Nesterov
2013-10-09 14:07 ` Peter Zijlstra
2013-10-09 14:17 ` Oleg Nesterov
2013-10-09 14:32 ` Ingo Molnar
2013-10-09 14:33 ` Peter Zijlstra
2013-10-09 14:46 ` Peter Zijlstra
2013-10-09 18:16 ` Jakub Jelinek
2013-10-09 18:54 ` Linus Torvalds
2013-10-09 19:02 ` Peter Zijlstra
2013-10-09 19:08 ` Jakub Jelinek
2013-10-10 6:22 ` Ingo Molnar
2013-10-10 6:51 ` Jakub Jelinek
2013-10-10 8:04 ` Jakub Jelinek
2013-10-10 8:24 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Ingo Molnar
2013-10-10 8:31 ` Jakub Jelinek
2013-10-10 8:45 ` Ingo Molnar
2013-10-10 8:55 ` [PATCH, -v2] compiler/gcc4: Add quirk for 'asm goto' miscompilation bug Ingo Molnar
2013-10-10 11:56 ` Peter Zijlstra
2013-10-10 12:32 ` Jakub Jelinek
2013-10-10 13:10 ` Peter Zijlstra
2013-10-10 15:04 ` Ingo Molnar
2013-10-10 14:04 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Richard Henderson
2013-10-10 14:27 ` Jakub Jelinek
2013-10-10 15:12 ` [PATCH, -v3] compiler/gcc4: Add quirk for 'asm goto' miscompilation bug Ingo Molnar
2013-10-10 16:15 ` Richard Henderson
2013-10-10 16:49 ` Ingo Molnar
2013-10-11 4:35 ` Fengguang Wu
2013-10-11 5:46 ` Ingo Molnar
2013-10-11 6:51 ` Fengguang Wu
2013-10-11 9:30 ` Fengguang Wu
2013-10-12 17:03 ` Ingo Molnar
2013-10-10 8:34 ` [PATCH] gcc4: Add 'asm goto' miscompilation quirk Ingo Molnar
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