From: Jan Engelhardt <jengelh@inai.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: NULL deref around blkmq in v4.0-rc1–rc7
Date: Fri, 10 Apr 2015 00:32:50 +0200 (CEST) [thread overview]
Message-ID: <alpine.LSU.2.20.1504100030270.14912@nerf40.vanv.qr> (raw)
In-Reply-To: <5526F25B.5010501@kernel.dk>
On Thursday 2015-04-09 23:42, Jens Axboe wrote:
>
>> So I don't actually expect my patch to really make any difference,
>> although I do think that code should be looked at.
>
> Jan, is it always clearing in a page size? That seems odd, especially if we're
> considering random gunk in memory.
The particular memset in scsi_init_cmd_errh would only clear
SCSI_SENSE_BUFFERSIZE. The problem really was that cmd->sense_buffer
was nonsensical (I did a hexdump) and read 0x1000. In one instance,
it even read 0x10000 because I used that value in an if clause
preceding a printk statement I added. Together with __GFP_ZERO
apparently fixing the issue for today, the noninitialized memory
theory looks like the most applicable one to me currently.
next prev parent reply other threads:[~2015-04-09 22:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-08 13:41 NULL deref around xfs " Jan Engelhardt
2015-04-08 15:20 ` Jan Engelhardt
2015-04-09 17:38 ` Linus Torvalds
2015-04-09 18:24 ` NULL deref around blkmq " Jan Engelhardt
2015-04-09 21:12 ` Linus Torvalds
2015-04-09 21:25 ` Jens Axboe
2015-04-09 21:37 ` Linus Torvalds
2015-04-09 21:42 ` Jens Axboe
2015-04-09 22:32 ` Jan Engelhardt [this message]
2015-04-09 22:29 ` Jan Engelhardt
2015-04-10 0:07 ` Linus Torvalds
2015-04-11 17:46 ` Linus Torvalds
2015-04-11 17:47 ` Jens Axboe
2015-04-11 19:48 ` Jan Engelhardt
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