From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f205.google.com (mail-il1-f205.google.com [209.85.166.205]) (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 73203283FEA for ; Mon, 20 Oct 2025 16:09:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.205 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760976572; cv=none; b=pWVXfoydoNQi0rZSMdO+0B10WVQmcjSv3HTN8A/xhpyGsUrWK3HuI0z84FD8m9F7NaIcU+iHM/EwPLA/MiNTPmKxA+p+DOCwGyS8bBUtnr5uyZyHfIX18056ahiYM4XTQM2dm8WNYERvAOqW+KBb75MhsuUSrifqwomvPPSP7Po= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760976572; c=relaxed/simple; bh=cKX7axGAua4wBOQ7vViFnnyY08CuouvVP8szBHpbHH4=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=lLDcWdNs5Hb8vG506kSSsfQQGT/xA+XBARrCd9/3ypNGRHdCmfmRKk0jMSc7A/9bCIxP+jySv+ENv6h7IuaWOD4Q93JjxMRTNqAYXIfrwO5MVh3yaOWzWRcYXAx24kPwW1Q87sjCydEKvEoCZeP3nZrCNo2aaNr70fOpXccn+wo= 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=209.85.166.205 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-il1-f205.google.com with SMTP id e9e14a558f8ab-430d1adb32aso19413135ab.1 for ; Mon, 20 Oct 2025 09:09:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760976569; x=1761581369; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=pbfF70cDDtAHBRC9nSIxTU9q86P/OB6WZ1gA9jNUyrg=; b=GYeHPQjmcUWRKHKRZ4wAYojGlLrW9t+mKvMXt8iJbkAAxQcY/BPdt9OEbzehRzH8qg sDyM6m3RcZK7pWFuj1rhwGvYRLFsytIqW2mpO4TKpb7Z7ZS4+k+buicXw6GGRuhHCE8c IF45IO4xMT2L/CqDVYHG7y6FaDa2DmauYsqchJvVjN2WBpzmjtIHh3TrDs045LG8osOB n0hTZIUELK7n0Th+ExxaNM1HRmTRZl3I5+vY8OwifpwGONLIolvk3DHX9GWbWHOGro8P mB+kf5RwxUowK15s/qvBFiBHipDd7yYgZvDb0mAjsGNAqoUeiCFVhZHVli4DUYR2yCDx maww== X-Forwarded-Encrypted: i=1; AJvYcCUIZv+IFYclffSY2cZTQx9hNHW//TbtK0NOQ+NBSclPEh+J52NmW0Ij934HgkkDomHWd4qAMR0SE3EWwcs=@vger.kernel.org X-Gm-Message-State: AOJu0Yz257s1LKv90I+oMxJaQGpoYmWTKifyBe5CfNN2JKC6otdvMPKO 57UK33Jz5CCY7tORyJ/BX+K44pL0K6BAzQERSQj7BDdF1NxSnTIv2a5gUWeunYBE3mcD+2qrGeR fPwQKGfqA6K17ziHb1W6QTvUxyJqnhDHGyce0b8Rr/Bvyl7Bq7qBcsv9Ul6M= X-Google-Smtp-Source: AGHT+IHYQTSzzfTWBjWfSVU0sprZlwQ9IxoWFFjnmAvndOeKFlOeFDGJlIqFloDQ99h7zzClGfhPq4Srx74v+eVNKlbeVAHa/O5P Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:1a46:b0:42b:2f98:3fc2 with SMTP id e9e14a558f8ab-430c52b4580mr193897435ab.17.1760976569555; Mon, 20 Oct 2025 09:09:29 -0700 (PDT) Date: Mon, 20 Oct 2025 09:09:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68f65eb9.a70a0220.205af.0034.GAE@google.com> Subject: [syzbot] [net?] possible deadlock in gro_cells_receive 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: cf1ea8854e4f Merge tag 'mmc-v6.18-rc1' of git://git.kernel.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12456492580000 kernel config: https://syzkaller.appspot.com/x/.config?x=af9170887d81dea1 dashboard link: https://syzkaller.appspot.com/bug?extid=f9651b9a8212e1c8906f compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a6a5b37662b9/disk-cf1ea885.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/4b4d732ae480/vmlinux-cf1ea885.xz kernel image: https://storage.googleapis.com/syzbot-assets/acd7feec5537/bzImage-cf1ea885.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f9651b9a8212e1c8906f@syzkaller.appspotmail.com ============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.2.329/7421 is trying to acquire lock: ffffe8ffffd48888 ((&cell->bh_lock)){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] ffffe8ffffd48888 ((&cell->bh_lock)){+...}-{3:3}, at: gro_cells_receive+0x404/0x790 net/core/gro_cells.c:30 but task is already holding lock: ffffe8ffffd48888 ((&cell->bh_lock)){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] ffffe8ffffd48888 ((&cell->bh_lock)){+...}-{3:3}, at: gro_cells_receive+0x404/0x790 net/core/gro_cells.c:30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock((&cell->bh_lock)); lock((&cell->bh_lock)); *** DEADLOCK *** May be due to missing lock nesting notation 8 locks held by syz.2.329/7421: #0: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: bpf_test_timer_enter+0x1e/0x2b0 net/bpf/test_run.c:40 #1: ffffffff8d64ab00 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0xa1/0x540 kernel/softirq.c:163 #2: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0xa1/0x540 kernel/softirq.c:163 #3: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #3: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: netif_receive_skb_list_internal+0x4fd/0xcb0 net/core/dev.c:6297 #4: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #4: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #4: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: ip6_input+0x23/0x270 net/ipv6/ip6_input.c:499 #5: ffffe8ffffd48888 ((&cell->bh_lock)){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] #5: ffffe8ffffd48888 ((&cell->bh_lock)){+...}-{3:3}, at: gro_cells_receive+0x404/0x790 net/core/gro_cells.c:30 #6: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #6: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #6: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: ip6_input+0x23/0x270 net/ipv6/ip6_input.c:499 #7: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #7: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #7: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: gro_cells_receive+0x50/0x790 net/core/gro_cells.c:21 stack backtrace: CPU: 1 UID: 0 PID: 7421 Comm: syz.2.329 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] gro_cells_receive+0x404/0x790 net/core/gro_cells.c:30 ip6_tnl_rcv+0x7c/0xa0 net/ipv6/ip6_tunnel.c:903 ip6gre_rcv net/ipv6/ip6_gre.c:-1 [inline] gre_rcv+0xbfa/0x11e0 net/ipv6/ip6_gre.c:588 ip6_protocol_deliver_rcu+0xe0b/0x15c0 net/ipv6/ip6_input.c:438 ip6_input_finish+0x191/0x370 net/ipv6/ip6_input.c:489 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500 dst_input include/net/dst.h:474 [inline] ip6_sublist_rcv_finish+0x1c8/0x2a0 net/ipv6/ip6_input.c:88 ip6_list_rcv_finish net/ipv6/ip6_input.c:145 [inline] ip6_sublist_rcv+0xb11/0xdd0 net/ipv6/ip6_input.c:321 ipv6_list_rcv+0x3e5/0x430 net/ipv6/ip6_input.c:355 __netif_receive_skb_list_ptype net/core/dev.c:6122 [inline] __netif_receive_skb_list_core+0x5f4/0x800 net/core/dev.c:6169 __netif_receive_skb_list net/core/dev.c:6221 [inline] netif_receive_skb_list_internal+0x96f/0xcb0 net/core/dev.c:6312 netif_receive_skb_list+0x54/0x450 net/core/dev.c:6364 xdp_recv_frames net/bpf/test_run.c:280 [inline] xdp_test_run_batch net/bpf/test_run.c:361 [inline] bpf_test_run_xdp_live+0x1790/0x1b20 net/bpf/test_run.c:390 bpf_prog_test_run_xdp+0x75b/0x10e0 net/bpf/test_run.c:1331 bpf_prog_test_run+0x2cd/0x340 kernel/bpf/syscall.c:4673 __sys_bpf+0x562/0x860 kernel/bpf/syscall.c:6152 __do_sys_bpf kernel/bpf/syscall.c:6244 [inline] __se_sys_bpf kernel/bpf/syscall.c:6242 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6242 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3bce98efc9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3bccbee038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f3bcebe5fa0 RCX: 00007f3bce98efc9 RDX: 0000000000000048 RSI: 0000200000000600 RDI: 000000000000000a RBP: 00007f3bcea11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3bcebe6038 R14: 00007f3bcebe5fa0 R15: 00007fffd6bba178 --- 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 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