From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Amir Goldstein <amir73il@gmail.com>,
Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] fsnotify: avoid gcc-10 zero-length-bounds warning
Date: Tue, 5 May 2020 10:11:39 -0500 [thread overview]
Message-ID: <1f33eec3-4851-e423-2d04-e02da25e2e6e@embeddedor.com> (raw)
In-Reply-To: <CAK8P3a0v-hK+Ury86-1D2_jfOFgR8ZTEFKVQZBWJq3dW=MuSzw@mail.gmail.com>
On 5/5/20 10:00, Arnd Bergmann wrote:
> On Tue, May 5, 2020 at 4:35 PM Gustavo A. R. Silva
> <gustavo@embeddedor.com> wrote:
>> On 5/5/20 09:30, Arnd Bergmann wrote:
>>> gcc-10 warns about accesses into the f_handle[] zero-length array.
>>>
>>> fs/notify/fdinfo.c: In function 'show_mark_fhandle':
>>> fs/notify/fdinfo.c:66:47: error: array subscript 'i' is outside the bounds of an interior zero-length array 'unsigned char[0]' [-Werror=zero-length-bounds]
>>> 66 | seq_printf(m, "%02x", (int)f.handle.f_handle[i]);
>>> | ~~~~~~~~~~~~~~~~~^~~
>>> In file included from fs/notify/fdinfo.c:3:
>>> include/linux/fs.h:988:16: note: while referencing 'f_handle'
>>> 988 | unsigned char f_handle[0];
>>> | ^~~~~~~~
>>>
>>> This is solved by using a flexible array instead.
>>>
>>> Cc: Gustavo A. R. Silva <gustavo@embeddedor.com>
>>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>>> ---
>>> Gustavo has done the same thing as part of a treewide change, but keeping
>>> this separate lets us backport it to stable kernels more easily later.
>>
>> Arnd,
>>
>> I wonder why would we need to backport these changes to -stable... merely
>> because of the use of a new version of GCC?
>
> Yes, we usually backport trivial warning fixes to stable kernels to allow
> building those with any modern compiler version.
>
OK. So, if you anticipate that this is going to happen, I can split up my
treewide patch into separate per-subsystem patches. I can replace the
treewide patch in my tree today, so the changes are reflected in tomorrow's
linux-next.
--
Gustavo
next prev parent reply other threads:[~2020-05-05 15:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 14:30 [PATCH] fsnotify: avoid gcc-10 zero-length-bounds warning Arnd Bergmann
2020-05-05 14:39 ` Gustavo A. R. Silva
2020-05-05 15:00 ` Arnd Bergmann
2020-05-05 15:11 ` Gustavo A. R. Silva [this message]
2020-05-05 15:23 ` Arnd Bergmann
2020-05-05 16:58 ` Linus Torvalds
2020-05-07 8:01 ` David Laight
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