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Date: Tue, 8 Oct 2013 18:33:45 -0700
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Subject: Re: [x86] BUG: unable to handle kernel NULL pointer dereference at (null)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Richard Henderson <rth@twiddle.net>, Jakub Jelinek <jakub@redhat.com>,
        Oleg Nesterov <oleg@redhat.com>
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On Tue, Oct 8, 2013 at 6:09 PM, Fengguang Wu <fengguang.wu@intel.com> wrote:
> [   27.189229] BUG: unable to handle kernel NULL pointer dereference at 00000108
> [   27.190165] IP: [<c1109200>] rw_verify_area+0xa0/0x1b0

This looks like file->f_inode is NULL, and it's trying to access inode->i_flock.

There's a number of other ones too (that last delayed __fput one, for
example) that might be due to a NULL inode.

And a lot of thre rest are file-handling too, with the BUG_ON() in
__put_cred() when there's something wrong with file->f_cred.

.. but I have no clue how that could happen and why the asm goto
should matter for this.

              Linus
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