From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
David Howells <dhowells@redhat.com>,
<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] pipe: fix potential use-after-free in pipe_read()
Date: Tue, 23 Nov 2021 09:09:42 +0800 [thread overview]
Message-ID: <3d1da34f-7b47-3d19-40ce-98b62d6e6f6d@huawei.com> (raw)
In-Reply-To: <YZJbBNs/63pnXngK@casper.infradead.org>
On 2021/11/15 21:05, Matthew Wilcox wrote:
> On Mon, Nov 15, 2021 at 02:13:44PM +0800, Leizhen (ThunderTown) wrote:
>>
>>
>> On 2021/11/15 12:25, Matthew Wilcox wrote:
>>> On Mon, Nov 15, 2021 at 11:57:20AM +0800, Zhen Lei wrote:
>>>> if (!buf->len) {
>>>> + unsigned int __maybe_unused flags = buf->flags;
>>>
>>> Why __maybe_unused?
>>
>> It's used only if "#ifdef CONFIG_WATCH_QUEUE". Otherwise, a warning will be reported.
>
> Better to turn the #ifdef into if (IS_ENABLED())
Hi, Matthew:
Thank you for your advice. IS_ENABLED() is a good idea, but when I tried it, I found that
the macro 'PIPE_BUF_FLAG_LOSS' and the structure member 'note_loss' were also separated by
"ifdef CONFIG_WATCH_QUEUE", so this method is not suitable here.
#ifdef CONFIG_WATCH_QUEUE
#define PIPE_BUF_FLAG_LOSS 0x40 /* Message loss happened after this buffer */
#endif
@@ -62,9 +60,7 @@ struct pipe_inode_info {
unsigned int tail;
unsigned int max_usage;
unsigned int ring_size;
#ifdef CONFIG_WATCH_QUEUE
bool note_loss;
#endif
> .
>
next prev parent reply other threads:[~2021-11-23 1:09 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-15 3:57 [PATCH 0/2] pipe: Fix a potential UAF and delete a duplicate line of code Zhen Lei
2021-11-15 3:57 ` [PATCH 1/2] pipe: fix potential use-after-free in pipe_read() Zhen Lei
2021-11-15 4:25 ` Matthew Wilcox
2021-11-15 6:13 ` Leizhen (ThunderTown)
2021-11-15 13:05 ` Matthew Wilcox
2021-11-23 1:09 ` Leizhen (ThunderTown) [this message]
2021-11-15 3:57 ` [PATCH 2/2] pipe: delete a duplicate line of code in pipe_write() Zhen Lei
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