From: Simon Horman <horms@kernel.org>
To: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: netdev@vger.kernel.org, Jiayuan Chen <jiayuan.chen@shopee.com>,
syzbot+d5ace703ed883df56e42@syzkaller.appspotmail.com,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Kees Cook <kees@kernel.org>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH net-next v1] net: sched: cls_u32: Avoid memcpy() false-positive warning in u32_init_knode()
Date: Mon, 9 Mar 2026 12:12:40 +0000 [thread overview]
Message-ID: <20260309121240.GH461701@kernel.org> (raw)
In-Reply-To: <20260305073343.250702-1-jiayuan.chen@linux.dev>
On Thu, Mar 05, 2026 at 03:33:43PM +0800, Jiayuan Chen wrote:
> From: Jiayuan Chen <jiayuan.chen@shopee.com>
>
> Syzbot reported a warning in u32_init_knode() [1].
>
> Similar to commit 7cba18332e36 ("net: sched: cls_u32: Avoid memcpy()
> false-positive warning") which addressed the same issue in u32_change(),
> use unsafe_memcpy() in u32_init_knode() to work around the compiler's
> inability to see into composite flexible array structs.
>
> This silences the false-positive reported by syzbot:
>
> memcpy: detected field-spanning write (size 32) of single field
> "&new->sel" at net/sched/cls_u32.c:855 (size 16)
>
> Since the memory is correctly allocated with kzalloc_flex() using
> s->nkeys, this is purely a false positive and does not need a Fixes tag.
>
> [1] https://syzkaller.appspot.com/bug?extid=d5ace703ed883df56e42
>
> Reported-by: syzbot+d5ace703ed883df56e42@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/all/69a811b9.a70a0220.b118c.0019.GAE@google.com/T/
> Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
> Made-with: Cursor
FWIIW, Made-with is a new tag to me, I would have expected Assisted-by.
That notwithstanding, this looks good to me.
Reviewed-by: Simon Horman <horms@kernel.org>
prev parent reply other threads:[~2026-03-09 12:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-05 7:33 [PATCH net-next v1] net: sched: cls_u32: Avoid memcpy() false-positive warning in u32_init_knode() Jiayuan Chen
2026-03-05 4:26 ` Gustavo A. R. Silva
2026-03-05 8:09 ` Jiayuan Chen
2026-03-05 4:13 ` Gustavo A. R. Silva
2026-03-09 12:12 ` Simon Horman [this message]
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