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Date: Sun, 21 Nov 2010 19:51:16 +0100 From: Oleg Nesterov <oleg@...hat.com> To: Linus Torvalds <torvalds@...ux-foundation.org> Cc: Pekka Enberg <penberg@...nel.org>, LKML <linux-kernel@...r.kernel.org>, Peter Zijlstra <peterz@...radead.org>, Andrew Morton <akpm@...ux-foundation.org>, Linux Netdev List <netdev@...r.kernel.org> Subject: Re: [PROBLEM] WARNING: at kernel/exit.c:910 do_exit On 11/21, Linus Torvalds wrote: > > On Sun, Nov 21, 2010 at 7:35 AM, Pekka Enberg <penberg@...nel.org> wrote: > > > > WARN_ON(atomic_read(&tsk->fs_excl)); > > > > in do_exit(). There was a prior oops in __pipe_free_info() called in > > sys_recvmsg() paths that unfortunately scrolled away. > > That WARN_ON() is almost certainly due to the previous oops. > > The previous oops may have scrolled away, but you can see the > call-chain, since it's part of the later oops. Except the photo is > hard to read ;) > > In fact, you can see that there has been _two_ oopses before that. The > "free_pipe_info()" oops comes from the "do_exit()" path of the _first_ > oops. > > So the original oops seems to be around here: > > (*probably* oopsed in __scm_destroy) > (the fd_install on the stack is likely from scm_detach_fds calling > it before calling __scm_destroy - just a stale pointer remaining on > the stack) > scm_detach_fds > unix_stream_recvmsg > sock_recvmsg > __sys_recvmsg > sys_recvmsg Yes, but still I am puzzled a bit. Where ->fs_excl != 0 comes from? Not that I really understand what it means, but nothing in this path can do lock_super(), I think. This means it was already nonzero or the bug caused the memory corruption. Btw, why it is atomic_t ? > And who knows? It may be that the networking oops was due to some > other earlier problem that isn't part of this particular callchain and > that has long since scrolled away. Agreed, probably this is false alarm. The oopsing task can trigger a lot of "wrong" warnings. Oleg. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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