From: Sedat Dilek <sedat.dilek@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>, Wim Van Sebroeck <wim@iguana.be>,
Ingo Molnar <mingo@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
linux-watchdog@vger.kernel.org, x86@kernel.org,
LKML <linux-kernel@vger.kernel.org>,
linux-next <linux-next@vger.kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [next-20130227] kernel NULL pointer dereference [ watchdog | perf related ? ]
Date: Thu, 28 Feb 2013 08:24:41 +0100 [thread overview]
Message-ID: <CA+icZUXGGQjKAwAET81pioAfZBw8mj3MO49Mm3xc35-UY=BgTg@mail.gmail.com> (raw)
In-Reply-To: <20130227150733.GB22383@htj.dyndns.org>
On Wed, Feb 27, 2013 at 4:07 PM, Tejun Heo <tj@kernel.org> wrote:
> Replying here too just in case.
>
> On Wed, Feb 27, 2013 at 02:08:40PM +0100, Sedat Dilek wrote:
>> >> static inline void *idr_find(struct idr *idr, int id)
>> >> {
>> >> struct idr_layer *hint = rcu_dereference_raw(idr->hint);
>> >> 86d7: 48 8b 05 00 00 00 00 mov 0x0(%rip),%rax # 86de <perf_init_event+0x2e>
>> >> 86da: R_X86_64_PC32 .bss+0xfc
>> >>
>> >> if ((id & ~IDR_MASK) == hint->prefix)
>> >> 86de: 89 f2 mov %esi,%edx
>> >> 86e0: 30 d2 xor %dl,%dl
>> >> 86e2: 3b 10 cmp (%rax),%edx <--- trapping insn
>> >> 86e4: 74 4a je 8730 <perf_init_event+0x80>
>> >> return rcu_dereference_raw(hint->ary[id & IDR_MASK]);
>> >>
>> >>
>> >> So 'hint' is NULL as RAX above confirms and we're not supposed to deref
>> >> NULL things.
>> >>
>> >> Looking at 29cf29e1fbb875019713eb55cf27ec35f1e5fa5e, Tejun should
>> >> probably know. CCed.
>
> Fix was posted some days ago.
>
> http://thread.gmane.org/gmane.linux.kernel.next/26213
>
> I got Andrew's patch added to -mm message a week ago. Not sure why it
> still hasn't showed up. Andrew, any ideas?
>
> Thanks.
>
> --
> tejun
AFAICS the updated (correct) patch "idr: implement lookup hint" is now
in mainline.
- Sedat -
[1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=0ffc2a9c8072969253a20821c2c733a2cbb4c7c7
next prev parent reply other threads:[~2013-02-28 7:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-27 11:13 [next-20130227] kernel NULL pointer dereference [ watchdog | perf related ? ] Sedat Dilek
2013-02-27 11:57 ` Wim Van Sebroeck
2013-02-27 12:23 ` Borislav Petkov
2013-02-27 12:51 ` Sedat Dilek
2013-02-27 13:08 ` Sedat Dilek
2013-02-27 15:07 ` Tejun Heo
2013-02-27 15:56 ` Sedat Dilek
2013-02-27 16:08 ` Borislav Petkov
2013-02-27 16:14 ` Sedat Dilek
2013-02-27 16:46 ` Borislav Petkov
2013-02-28 7:24 ` Sedat Dilek [this message]
2013-02-28 7:27 ` Sedat Dilek
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