From: Chris Wright <chrisw@sous-sol.org>
To: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Matt Helsley <matthltc@us.ibm.com>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] Replacing the /proc/<pid|self>/exe symlink code
Date: Wed, 30 May 2007 23:01:48 -0700 [thread overview]
Message-ID: <20070531060148.GE3390@sequoia.sous-sol.org> (raw)
In-Reply-To: <20070530180923.GA22345@vino.hallyn.com>
* Serge E. Hallyn (serge@hallyn.com) wrote:
> > ===================================================================
> > --- linux-2.6.22-rc2-mm1.orig/kernel/exit.c
> > +++ linux-2.6.22-rc2-mm1/kernel/exit.c
> > @@ -924,10 +924,12 @@ fastcall void do_exit(long code)
> > if (unlikely(tsk->audit_context))
> > audit_free(tsk);
> >
> > taskstats_exit(tsk, group_dead);
> >
> > + if (tsk->exe_file)
> > + fput(tsk->exe_file);
>
> just taking a cursory look so I may be missing something, but doesn't
> this leave the possibility that right here, with tsk->exe_file being
> put, another task would try to look at tsk's /proc/tsk->pid/exe?
And I hit this one, so there's at least one issue.
[ 110.296952] Unable to handle kernel NULL pointer dereference at 0000000000000088 RIP:
[ 110.299053] [<ffffffff80293fca>] d_path+0x1a/0x117
[ 110.301861] PGD 6d35a067 PUD 6d35e067 PMD 0
[ 110.303509] Oops: 0000 [1] SMP
[ 110.304719] CPU 1
[ 110.305493] Modules linked in: oprofile
[ 110.306969] Pid: 3983, comm: pidof Not tainted 2.6.22-rc3-g7f397dcd-dirty #183
[ 110.309733] RIP: 0010:[<ffffffff80293fca>] [<ffffffff80293fca>] d_path+0x1a/0x117
[ 110.312635] RSP: 0018:ffff810142335e38 EFLAGS: 00010292
[ 110.314667] RAX: ffff81006d58a000 RBX: 0000000000000000 RCX: 0000000000001000
[ 110.317397] RDX: ffff81006d58a000 RSI: 0000000000000000 RDI: 0000000000000000
[ 110.320127] RBP: ffff81006d58a000 R08: 00000000fffffff3 R09: 000000000006be8b
[ 110.322857] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
[ 110.325588] R13: 0000000000001000 R14: ffff81006d58a000 R15: 00000000000000000
[ 110.328319] FS: 00002b033d578260(0000) GS:ffff81000106e480(0000) knlGS:0000000000000000
[ 110.331415] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 110.333613] CR2: 0000000000000088 CR3: 000000006cf54000 CR4: 00000000000006e0
[ 110.336344] Process pidof (pid: 3983, threadinfo ffff810142334000, task ffff8101421186c0)
[ 110.339472] Stack: ffff8101422a7268 0000000000000000 ffff81006d58a000 00000000fffffff4
[ 110.342556] 0000000000000000 0000000000001000 0000000000678820 ffffffff802b7a54
[ 110.345404] 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 110.348180] Call Trace:
[ 110.349188] [<ffffffff802b7a54>] proc_pid_readlink+0x89/0xff
[ 110.351387] [<ffffffff80285e55>] sys_readlinkat+0x87/0xa9
[ 110.353487] [<ffffffff8026d4dc>] remove_vma+0x5d/0x64
[ 110.355455] [<ffffffff80596acd>] error_exit+0x0/0x84
[ 110.357389] [<ffffffff8020935e>] system_call+0x7e/0x83
[ 110.359388]
[ 110.359958]
[ 110.359958] Code: 48 8b 87 88 00 00 00 48 85 c0 74 20 48 8b 40 30 48 85 c0 74
[ 110.363381] RIP [<ffffffff80293fca>] d_path+0x1a/0x117
[ 110.365386] RSP <ffff810142335e38>
[ 110.366720] CR2: 0000000000000088
--
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next prev parent reply other threads:[~2007-05-31 6:01 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-30 0:52 Matt Helsley
2007-05-30 18:09 ` Serge E. Hallyn
2007-05-31 6:01 ` Chris Wright [this message]
2007-06-01 1:13 ` Matt Helsley
2007-05-31 17:56 ` Matt Helsley
2007-06-01 22:31 ` Serge E. Hallyn
2007-06-02 0:42 ` Matt Helsley
2007-06-02 0:46 Matt Helsley
2007-06-06 22:21 ` Serge E. Hallyn
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