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AHgh+Ro36b/VM55SefutTKcXZ3G9k3kk8qoDJHTqkD3DM4w4tNN3SDWlyKwirsAdbDqDvE52JvLcbAqLctgTsk0=@vger.kernel.org X-Gm-Message-State: AFuF++lmTKiB4hI0Kg6L0XVx3rvLHkuSqbfC4nct7+B6Ejpyc+5VV1eI w/5Qaw5Hw87RBS9tt9ROEGk8euv6B/icwO/uR/2zFeLBQaoEAevkP1MiRth9SPKDyFlg5jKZ718 fbHsY0D689SXOyKkRVyQ4xPpINWwNlZJtuEGLs3UNTRS3QuNFQe2rONe5M1A= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:e84b:0:b0:6ae:8ee4:e01f with SMTP id 006d021491bc7-6b1a036fadcmr4938203eaf.4.1787739454870; Wed, 26 Aug 2026 03:17:34 -0700 (PDT) Date: Wed, 26 Aug 2026 03:17:34 -0700 In-Reply-To: <6a8bd82a.dbb3a75c.13dd47.0061.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a8ebd3e.1d9ded08.62e62.00a3.GAE@google.com> Subject: Re: [syzbot] [usb-storage?] divide error in alauda_transport From: syzbot To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, stern@rowland.harvard.edu, syzkaller-bugs@googlegroups.com, usb-storage@lists.one-eyed-alien.net Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 818bebeb63dd drm/xe: Don't hand out the flat CCS storage a.. git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=157ff979580000 kernel config: https://syzkaller.appspot.com/x/.config?x=ccca94d2c01b9e78 dashboard link: https://syzkaller.appspot.com/bug?extid=dc208a8cf8d37cf3e5ac compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=113d1625580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+dc208a8cf8d37cf3e5ac@syzkaller.appspotmail.com Oops: divide error: 0000 [#1] SMP KASAN NOPTI CPU: 1 UID: 0 PID: 6620 Comm: usb-storage Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:953 [inline] RIP: 0010:alauda_transport+0xe5a/0x35c0 drivers/usb/storage/alauda.c:1187 Code: 01 45 85 ed 0f 84 6d 1c 00 00 c7 04 24 00 00 00 00 8b 5c 24 20 e8 46 38 53 fa 31 d2 48 8b 7c 24 08 89 d8 89 5c 24 20 41 89 df 74 24 70 89 c3 89 54 24 10 89 de e8 05 c1 ff ff 44 0f b7 74 24 RSP: 0018:ffffc900044ff9d0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87b7c98a RDI: ffff8880578f8e90 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880d5ca2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f741d1ca6e4 CR3: 0000000054fb4000 CR4: 0000000000352ef0 Call Trace: usb_stor_invoke_transport+0xe7/0x15c0 drivers/usb/storage/transport.c:611 usb_stor_control_thread+0x5e4/0xae0 drivers/usb/storage/usb.c:462 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:953 [inline] RIP: 0010:alauda_transport+0xe5a/0x35c0 drivers/usb/storage/alauda.c:1187 Code: 01 45 85 ed 0f 84 6d 1c 00 00 c7 04 24 00 00 00 00 8b 5c 24 20 e8 46 38 53 fa 31 d2 48 8b 7c 24 08 89 d8 89 5c 24 20 41 89 df 74 24 70 89 c3 89 54 24 10 89 de e8 05 c1 ff ff 44 0f b7 74 24 RSP: 0018:ffffc900044ff9d0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87b7c98a RDI: ffff8880578f8e90 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880d5ca2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f741d1ca6e4 CR3: 0000000054fb4000 CR4: 0000000000352ef0 ---------------- Code disassembly (best guess): 0: 01 45 85 add %eax,-0x7b(%rbp) 3: ed in (%dx),%eax 4: 0f 84 6d 1c 00 00 je 0x1c77 a: c7 04 24 00 00 00 00 movl $0x0,(%rsp) 11: 8b 5c 24 20 mov 0x20(%rsp),%ebx 15: e8 46 38 53 fa call 0xfa533860 1a: 31 d2 xor %edx,%edx 1c: 48 8b 7c 24 08 mov 0x8(%rsp),%rdi 21: 89 d8 mov %ebx,%eax 23: 89 5c 24 20 mov %ebx,0x20(%rsp) 27: 41 89 df mov %ebx,%r15d * 2a: f7 74 24 70 divl 0x70(%rsp) <-- trapping instruction 2e: 89 c3 mov %eax,%ebx 30: 89 54 24 10 mov %edx,0x10(%rsp) 34: 89 de mov %ebx,%esi 36: e8 05 c1 ff ff call 0xffffc140 3b: 44 rex.R 3c: 0f .byte 0xf 3d: b7 74 mov $0x74,%bh 3f: 24 .byte 0x24 --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.