From: Juergen Gross <jgross@suse.com>
To: Jan Beulich <jbeulich@suse.com>,
Rustam Subkhankulov <subkhankulov@ispras.ru>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
Alexey Khoroshilov <khoroshilov@ispras.ru>,
ldv-project@linuxtesting.org
Subject: Re: [POSSIBLE BUG] Dereferencing of NULL pointer
Date: Wed, 24 Aug 2022 16:00:54 +0200 [thread overview]
Message-ID: <0fcf74d8-774f-1999-d508-b8349096d83e@suse.com> (raw)
In-Reply-To: <0f5f26d2-2b22-2a0d-8bb2-ee2e729ada3f@suse.com>
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On 24.08.22 15:59, Jan Beulich wrote:
> On 20.08.2022 19:30, Rustam Subkhankulov wrote:
>> Version: 6.0-rc1
>>
>> Description:
>>
>> In function 'privcmd_ioctl_dm_op' (drivers/xen/privcmd.c: 615)return
>> value of 'kcalloc' with GFP_KERNEL flag is assigned to "pages"
>> variable. GFP_KERNEL flag does not guarantee, that the return value
>> will not be NULL. In that case, there is a jump to the "out" label.
>
> The problem is wider than that, because earlier errors would also
> lead to "out" (e.g. after copy_from_user() failed). Plus I guess
> unlock_pages() shouldn't be called at all (or with its 2nd arg set
> to zero) before lock_pages() was actually called. But I agree with
> the further analysis below. Would you mind sending a patch?
Just started writing it. :-)
Juergen
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prev parent reply other threads:[~2022-08-24 14:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-20 17:30 Rustam Subkhankulov
2022-08-24 13:59 ` Jan Beulich
2022-08-24 14:00 ` Juergen Gross [this message]
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