From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f80.google.com (mail-oo1-f80.google.com [209.85.161.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CFBC27F19F for ; Sun, 5 Jul 2026 06:26:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783232789; cv=none; b=uhvMuMbWAL9Y5gu8pL2oQMf7TOa9JW3D3D6r6Ol/s9qs/E4+9rBohzGC1tfig761UowWWCh1zdsodC9F7OhMzjhK3PW0u61wCBqtdZiBXISwwdz/ugQDMRoxHdOc2N7L6H34Ob/Tgj0MxJoq7nPAyFy0I2h4JeB59l/4G0BS+W4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783232789; c=relaxed/simple; bh=ZRLxZgqyN3T0N9JKVPeoWIHBqUGsTyu6ztiO6yyBCS0=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=XcPfUfo1+N7j2NsXWgDvlxoGVXY+/7LLD4Jr9AaBDHfNVsZV8tq1KAegcD+HyZ+2tJZLqLbRM6niMJUEe1Jvv51UNK7G27RrecWSrHb4MdS+dP6yT0900erUdgq0dzaGXIHtsEpalrGn7nT/4fqnVqeBwEzgPo5TmhQK63cAO/I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.80 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f80.google.com with SMTP id 006d021491bc7-6a18e349abfso2678426eaf.0 for ; Sat, 04 Jul 2026 23:26:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783232787; x=1783837587; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=VYjiezpgYlbe1rCtBCbicnJESVBKCFTSbnvtIUSvla0=; b=guaiYEF3+9nZowJRUoEJ5YYiLI1GK15x5LUlvRTmLvisWgmmjvLYkjlqvhtWfM7OVn J/qi3aj57jNm1LcVNR0L81VU0BZeSZR9kqU+JxFe5o1c/er9xjggeMoVYte9Cjijz/Uj E2HQJoDGLgxotuIxRv1QC1r6gcUgcYldbjopbYINQiSgX6PNE3vPt8A8i7aByOrlw61e Ivv1ij4qt+LGKgOnzdqcJHX01wP1y6mztukn8Ty1jAtdr2bdiwKDbLhXoZMIM0vBaUmM RrbFxHIqg4vSDBEBlvyAS04x5FimuvaxIXMIVZrXOJnwyPVp1B1EEAa727p8nT5L3Ll3 /nxw== X-Forwarded-Encrypted: i=1; AFNElJ9/nizs4dBzD46uye+N1Qa2dNRzKzGPSRxAsA/HnymeX3Yx9H7Y5tFBA5DYMH1+gxhdjb+hebY=@vger.kernel.org X-Gm-Message-State: AOJu0YxDUb9cnKdhDgK+8G8pUJXYT2i05cBL2HeCZ95ZUTo09t36Gh4Y a1G9f9n4iCPZ12a+KfYDk6ev8r+a2k6CdOypxoy61cRpCndncnZH7Sd+DJJ9SXNNHA6FjgSyeL+ BxSJL9CxIeiIuyZvAckgk+AzDbm2QVwctJuVGD1yavJsmjYJ8VCKuWM/fDjg= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:81c1:b0:6a1:1ccd:d09d with SMTP id 006d021491bc7-6a31d636ccbmr5266884eaf.42.1783232787391; Sat, 04 Jul 2026 23:26:27 -0700 (PDT) Date: Sat, 04 Jul 2026 23:26:27 -0700 In-Reply-To: <694ebdbd.050a0220.35954c.0077.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a49f913.52c20a74.1f8b39.0011.GAE@google.com> Subject: Re: [syzbot] [net?] WARNING in rcu_note_context_switch (5) 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" syzbot has found a reproducer for the following issue on: HEAD commit: b73bc9ca3686 Merge tag 'nf-next-26-07-02' of https://git.k.. git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=1043ef19580000 kernel config: https://syzkaller.appspot.com/x/.config?x=5c4196ba0e33631d dashboard link: https://syzkaller.appspot.com/bug?extid=84d4a405ed798b40c96d compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11d07719580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1443ef19580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/b7f8c662a498/disk-b73bc9ca.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/d3ffbd688a32/vmlinux-b73bc9ca.xz kernel image: https://storage.googleapis.com/syzbot-assets/235149e2b678/bzImage-b73bc9ca.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+84d4a405ed798b40c96d@syzkaller.appspotmail.com ------------[ cut here ]------------ Voluntary context switch within RCU read-side critical section! WARNING: kernel/rcu/tree_plugin.h:332 at rcu_note_context_switch+0xc58/0xef0 kernel/rcu/tree_plugin.h:332, CPU#1: syz.0.17/5817 Modules linked in: CPU: 1 UID: 0 PID: 5817 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:rcu_note_context_switch+0xc58/0xef0 kernel/rcu/tree_plugin.h:332 Code: 00 41 c6 45 00 00 48 8b 3d 35 15 ab 0e 48 81 c4 a8 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d e9 af 60 ff ff 48 8d 3d c8 d6 ae 0e <67> 48 0f b9 3a e9 6f f4 ff ff 90 0f 0b 90 45 84 e4 0f 84 3e f4 ff RSP: 0018:ffffc90002eced20 EFLAGS: 00010002 RAX: 0000000000000000 RBX: ffff888030d80000 RCX: 0000000080000002 RDX: 0000000000000000 RSI: ffffffff8c4bd260 RDI: ffffffff905ad640 RBP: dffffc0000000000 R08: ffffffff905767f7 R09: 1ffffffff20aecfe R10: dffffc0000000000 R11: fffffbfff20aecff R12: 0000000000000000 R13: dffffc0000000000 R14: ffff8880b873c180 R15: ffff888030d804c4 FS: 000055557f679500(0000) GS:ffff888125060000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff0e1073780 CR3: 0000000022684000 CR4: 00000000003526f0 Call Trace: __schedule+0x2e9/0x56c0 kernel/sched/core.c:7088 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 netlink_broadcast_filtered+0xe53/0xea0 net/netlink/af_netlink.c:1553 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xe3/0x1a0 net/netlink/af_netlink.c:2599 __ip6_del_rt_siblings+0x5ed/0x7d0 net/ipv6/route.c:4080 ip6_route_del+0x104f/0x1100 net/ipv6/route.c:4220 inet6_rtm_delroute+0x5d7/0x6d0 net/ipv6/route.c:5657 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7076 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff0e119de59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd842e7d98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ff0e1425fa0 RCX: 00007ff0e119de59 RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000004 RBP: 00007ff0e1233e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff0e1425fac R14: 00007ff0e1425fa0 R15: 00007ff0e1425fa0 ---------------- Code disassembly (best guess): 0: 00 41 c6 add %al,-0x3a(%rcx) 3: 45 00 00 add %r8b,(%r8) 6: 48 8b 3d 35 15 ab 0e mov 0xeab1535(%rip),%rdi # 0xeab1542 d: 48 81 c4 a8 00 00 00 add $0xa8,%rsp 14: 5b pop %rbx 15: 41 5c pop %r12 17: 41 5d pop %r13 19: 41 5e pop %r14 1b: 41 5f pop %r15 1d: 5d pop %rbp 1e: e9 af 60 ff ff jmp 0xffff60d2 23: 48 8d 3d c8 d6 ae 0e lea 0xeaed6c8(%rip),%rdi # 0xeaed6f2 * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: e9 6f f4 ff ff jmp 0xfffff4a3 34: 90 nop 35: 0f 0b ud2 37: 90 nop 38: 45 84 e4 test %r12b,%r12b 3b: 0f .byte 0xf 3c: 84 3e test %bh,(%rsi) 3e: f4 hlt 3f: ff .byte 0xff --- 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.