Received-SPF: pass (google.com: domain of linux-kernel+bounces-181925-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
From: Kuniyuki Iwashima <kuniyu@amazon.com>
To: <samsun1006219@gmail.com>
CC: <davem@davemloft.net>, <dsahern@kernel.org>, <edumazet@google.com>,
	<kuba@kernel.org>, <linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
	<pabeni@redhat.com>, <syzkaller-bugs@googlegroups.com>,
	<xrivendell7@gmail.com>, <kuniyu@amazon.com>
Subject: Re: [Linux kernel bug] UBSAN: shift-out-of-bounds in dctcp_update_alpha
Date: Fri, 17 May 2024 18:27:30 +0900
Message-ID: <20240517092730.34061-1-kuniyu@amazon.com>
In-Reply-To: <CAEkJfYNJM=cw-8x7_Vmj1J6uYVCWMbbvD=EFmDPVBGpTsqOxEA@mail.gmail.com>
References: <CAEkJfYNJM=cw-8x7_Vmj1J6uYVCWMbbvD=EFmDPVBGpTsqOxEA@mail.gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain

From: Sam Sun <samsun1006219@gmail.com>
Date: Fri, 17 May 2024 13:03:18 +0800
> Dear developers and maintainers,
> 
> We encountered a shift-out-of-bounds bug while using our modified
> syzkaller. It was tested against the latest upstream kernel (6.9). The
> kernel was compiled by clang 14.0.0, and kernel config and C repro are
> attached to this email. Kernel crash log is listed below.
> ------------[ cut here ]------------
> UBSAN: shift-out-of-bounds in net/ipv4/tcp_dctcp.c:143:12

Just for the record, I posted a patch:

https://lore.kernel.org/netdev/20240517091626.32772-1-kuniyu@amazon.com/