From: Qian Cai <cai@lca.pw>
To: James Bottomley <jejb@linux.ibm.com>,
Esme <esploit@protonmail.ch>,
"dgilbert@interlog.com" <dgilbert@interlog.com>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: PROBLEM: syzkaller found / pool corruption-overwrite / page in user-area or NULL
Date: Thu, 10 Jan 2019 15:39:51 -0500 [thread overview]
Message-ID: <1547152791.6911.6.camel@lca.pw> (raw)
In-Reply-To: <1547150339.2814.9.camel@linux.ibm.com>
On Thu, 2019-01-10 at 11:58 -0800, James Bottomley wrote:
> On Thu, 2019-01-10 at 19:12 +0000, Esme wrote:
> > Sorry for the resend some mail servers rejected the mime type.
> >
> > Hi, I've been getting more into Kernel stuff lately and forged ahead
> > with some syzkaller bug finding. I played with reducing it further
> > as you can see from the attached c code but am moving on and hope to
> > get better about this process moving forward as I'm still building
> > out my test systems/debugging tools.
> >
> > Attached is the report and C repro that still triggers on a fresh git
> > pull as of a few minutes ago, if you need anything else please let me
> > know.
> > Esme
> >
> > Linux syzkaller 5.0.0-rc1+ #5 SMP Tue Jan 8 20:39:33 EST 2019 x86_64
> > GNU/Linux
>
> I'm not sure I'm reading this right, but it seems that a simple
> allocation inside block/scsi_ioctl.h
>
> buffer = kzalloc(bytes, q->bounce_gfp | GFP_USER| __GFP_NOWARN);
>
> (where bytes is < 4k) caused a slub padding check failure on free.
> From the internal details, the freeing entity seems to be KASAN as part
> of its quarantine reduction (albeit triggered by this kzalloc). I'm
> not remotely familiar with what KASAN is doing, but it seems the memory
> corruption problem is somewhere within the KASAN tracking?
>
> I added linux-mm in case they can confirm this diagnosis or give me a
> pointer to what might be wrong in scsi.
>
Did you enable page_poison with PAGE_POISONING_ZERO=y ?
next prev parent reply other threads:[~2019-01-10 20:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <t78EEfgpy3uIwPUvqvmuQEYEWKG9avWzjUD3EyR93Qaf_tfx1gqt4XplrqMgdxR1U9SsrVdA7G9XeUZacgUin0n6lBzoxJHVJ9Ko0yzzrxI=@protonmail.ch>
2019-01-10 19:58 ` James Bottomley
2019-01-10 19:58 ` James Bottomley
2019-01-10 20:39 ` Qian Cai [this message]
2019-01-10 20:39 ` Qian Cai
2019-01-10 20:44 ` Qian Cai
2019-01-10 20:44 ` Qian Cai
2019-01-10 20:47 ` Esme
2019-01-10 21:03 ` Qian Cai
2019-01-10 21:10 ` Esme
2019-01-10 21:35 ` Esme
2019-01-10 22:33 ` Qian Cai
2019-01-10 22:58 ` Esme
2019-01-11 1:30 ` Qian Cai
2019-01-11 3:15 ` Esme
2019-01-11 4:52 ` Qian Cai
2019-01-11 5:01 ` Esme
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