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AJvYcCXYF8isaK3/6zhuStggbh89qFIrk3L8X0pIoi7S20nbVrYVhEx2d250GF8HC9s1vu2TkFVG7yHWHiaC2xE=@vger.kernel.org X-Gm-Message-State: AOJu0YzkHnUYoknzD9eAMoVO9Z3Ev9p2gp5rVH6ASfL9BzOckz/iiGPx MCAeoMuLONysF/HCAxFIMDxa/+8bg9MjsLhTPWydYaoZ2qJunBsz85gw5Jm73qPkH43fBcyl4Ds Hhtg/x+Ygdr/h7bvuou3jod3RBkWqdq8P2D2fhzqk+R4zbQncmQZVnbIOM0I= X-Google-Smtp-Source: AGHT+IFCRAfw28e98qC/9ugvEMowkcuK8yggxpTve8KozzLys5D6kuQDwQvvWthTuc0dKuCHWiDon8FCqdVF3WHFHA8px5N7LapV Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:178a:b0:434:96ea:ca19 with SMTP id e9e14a558f8ab-435b913657cmr136188375ab.17.1764100227216; Tue, 25 Nov 2025 11:50:27 -0800 (PST) Date: Tue, 25 Nov 2025 11:50:27 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69260883.a70a0220.d98e3.00b5.GAE@google.com> Subject: [syzbot] [net?] [can?] KMSAN: uninit-value in em_canid_match From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, jhs@mojatatu.com, jiri@resnulli.us, kuba@kernel.org, linux-can@vger.kernel.org, linux-kernel@vger.kernel.org, mkl@pengutronix.de, netdev@vger.kernel.org, pabeni@redhat.com, socketcan@hartkopp.net, syzkaller-bugs@googlegroups.com, xiyou.wangcong@gmail.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: ac3fd01e4c1e Linux 6.18-rc7 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1703e612580000 kernel config: https://syzkaller.appspot.com/x/.config?x=61a9bf3cc5d17a01 dashboard link: https://syzkaller.appspot.com/bug?extid=5d8269a1e099279152bc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12040e58580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117d797c580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/227434a45737/disk-ac3fd01e.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/d8117003dbb5/vmlinux-ac3fd01e.xz kernel image: https://storage.googleapis.com/syzbot-assets/a13125fb7a7d/bzImage-ac3fd01e.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5d8269a1e099279152bc@syzkaller.appspotmail.com syzkaller0: entered promiscuous mode syzkaller0: entered allmulticast mode ===================================================== BUG: KMSAN: uninit-value in em_canid_match+0x2f0/0x360 net/sched/em_canid.c:104 em_canid_match+0x2f0/0x360 net/sched/em_canid.c:104 tcf_em_match net/sched/ematch.c:494 [inline] __tcf_em_tree_match+0x215/0xc70 net/sched/ematch.c:520 tcf_em_tree_match include/net/pkt_cls.h:512 [inline] basic_classify+0x154/0x480 net/sched/cls_basic.c:50 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x855/0x1cb0 net/sched/cls_api.c:1860 multiq_classify net/sched/sch_multiq.c:39 [inline] multiq_enqueue+0x82/0x590 net/sched/sch_multiq.c:66 dev_qdisc_enqueue net/core/dev.c:4118 [inline] __dev_xmit_skb net/core/dev.c:4214 [inline] __dev_queue_xmit+0x1d91/0x5e60 net/core/dev.c:4729 dev_queue_xmit include/linux/netdevice.h:3365 [inline] packet_xmit+0x8f/0x710 net/packet/af_packet.c:275 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x9173/0xa2a0 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x333/0x3d0 net/socket.c:742 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2630 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2719 x64_sys_call+0x1dfd/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4985 [inline] slab_alloc_node mm/slub.c:5288 [inline] kmem_cache_alloc_node_noprof+0x989/0x16b0 mm/slub.c:5340 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:579 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:670 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6671 sock_alloc_send_pskb+0xacc/0xc60 net/core/sock.c:2965 packet_alloc_skb net/packet/af_packet.c:2926 [inline] packet_snd net/packet/af_packet.c:3019 [inline] packet_sendmsg+0x743d/0xa2a0 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x333/0x3d0 net/socket.c:742 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2630 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2719 x64_sys_call+0x1dfd/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 6067 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 ===================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title 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. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup