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AJvYcCXOTX0OTfunHIO8mAx4TGRw6Z20tYW9KTO04Lyxs9tb+qU++zzS1lLtviGfO1QCsF4VEXfATGt9pYI0cGo=@vger.kernel.org X-Gm-Message-State: AOJu0YyA+XJSCDcrT1FmEjg9OwadWph0owJsG6QJg4l/N6j+bLBlb+rK n5zuAPslhRJ9bXp8ULVi59lv96lVILRoaQIjzWdtbiaqbXwm2iW8dXV+2IvyTr9QofBMLMkWiBv MxCBBvEjcDy3FOMdE0yXoOCAO/6CAfLP5D8AWqE49/0CwQPQ4/B+od/59WvU= X-Google-Smtp-Source: AGHT+IE+pj8HxWzSaXbI0SzfT0bEp0JkiBJLWb/+1hCkcuoF1blP8RtnWH0W6IBoejnPUROPCIZd1S4pXCmO2Q9/HqPVs8CjYLOt Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:3992:b0:433:308c:19a6 with SMTP id e9e14a558f8ab-435b8c2b893mr198281925ab.12.1764331165715; Fri, 28 Nov 2025 03:59:25 -0800 (PST) Date: Fri, 28 Nov 2025 03:59:25 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69298e9d.a70a0220.d98e3.013a.GAE@google.com> Subject: [syzbot] [net?] KMSAN: uninit-value in lec_atm_send From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.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=139a1612580000 kernel config: https://syzkaller.appspot.com/x/.config?x=61a9bf3cc5d17a01 dashboard link: https://syzkaller.appspot.com/bug?extid=5dd615f890ddada54057 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=10f4b8b4580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=129d0e58580000 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+5dd615f890ddada54057@syzkaller.appspotmail.com ===================================================== BUG: KMSAN: uninit-value in lec_arp_update net/atm/lec.c:1845 [inline] BUG: KMSAN: uninit-value in lec_atm_send+0x2b02/0x55b0 net/atm/lec.c:385 lec_arp_update net/atm/lec.c:1845 [inline] lec_atm_send+0x2b02/0x55b0 net/atm/lec.c:385 vcc_sendmsg+0x1052/0x1190 net/atm/common.c:650 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] vcc_sendmsg+0x602/0x1190 net/atm/common.c:628 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: 6068 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