From: linmiaohe <linmiaohe@huawei.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: "axboe@kernel.dk" <axboe@kernel.dk>,
"satyat@google.com" <satyat@google.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] block: Fix potential NULL pointer dereference in __bio_crypt_clone()
Date: Wed, 2 Sep 2020 01:56:53 +0000 [thread overview]
Message-ID: <1a8ac4099d274d2b994a417c034fa3c6@huawei.com> (raw)
Eric Biggers <ebiggers@kernel.org> wrote:
>On Tue, Sep 01, 2020 at 07:59:21AM -0400, Miaohe Lin wrote:
>> mempool_alloc() may return NULL if __GFP_DIRECT_RECLAIM is not set in
>> gfp_mask under memory pressure. So we should check the return value of
>> mempool_alloc() against NULL before dereference.
>>
>> Fixes: a892c8d52c02 ("block: Inline encryption support for blk-mq")
>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>
>It's intended that __GFP_DIRECT_RECLAIM always be set here.
>Do you have an example where it isn't set here?
map_request() only pass GFP_ATOMIC to gfp_mask, though bio crypt is not used yet.
>Also, if this can indeed happen, then we need to make __bio_crypt_clone() (and bio_crypt_clone()) return a bool (or an error code) to indicate whether it succeeded or failed. We can't just ignore the allocation failure.
>
>- Eric
IMO, just the allocation failure is ok or we would break KABI.
Many thanks.
next reply other threads:[~2020-09-02 1:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-02 1:56 linmiaohe [this message]
2020-09-02 5:22 ` Eric Biggers
-- strict thread matches above, loose matches on Subject: below --
2020-09-01 11:59 Miaohe Lin
2020-09-01 16:07 ` Eric Biggers
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