From: Peter Xu <peterx@redhat.com>
To: manas18244@iiitd.ac.in
Cc: Andrew Morton <akpm@linux-foundation.org>,
Shuah Khan <skhan@linuxfoundation.org>,
Anup Sharma <anupnewsmail@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
syzbot+093d096417e7038a689b@syzkaller.appspotmail.com
Subject: Re: [PATCH v4] Fixes: null pointer dereference in pfnmap_lockdep_assert
Date: Mon, 7 Oct 2024 09:25:00 -0400 [thread overview]
Message-ID: <ZwPhLFIk4gvhn10d@x1n> (raw)
In-Reply-To: <20241004-fix-null-deref-v4-1-d0a8ec01ac85@iiitd.ac.in>
On Fri, Oct 04, 2024 at 11:12:16PM +0530, Manas via B4 Relay wrote:
> From: Manas <manas18244@iiitd.ac.in>
>
> syzbot has pointed to a possible null pointer dereference in
> pfnmap_lockdep_assert. vm_file member of vm_area_struct is being
> dereferenced without any checks.
>
> This fix assigns mapping only if vm_file is not NULL.
>
> Reported-by: syzbot+093d096417e7038a689b@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=093d096417e7038a689b
> ---
> This bug[1] triggers a general protection fault in follow_pfnmap_start
> function. An assertion pfnmap_lockdep_assert inside this function
> dereferences vm_file member of vm_area_struct. And panic gets triggered
> when vm_file is NULL.
>
> This patch assigns mapping only if vm_file is not NULL.
>
> [1] https://syzkaller.appspot.com/bug?extid=093d096417e7038a689b
>
> Signed-off-by: Manas <manas18244@iiitd.ac.in>
Reviewed-by: Peter Xu <peterx@redhat.com>
--
Peter Xu
prev parent reply other threads:[~2024-12-05 15:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-04 17:42 Manas via B4 Relay
2024-10-07 13:25 ` Peter Xu [this message]
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