From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f208.google.com (mail-oi1-f208.google.com [209.85.167.208]) (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 BF9462C0271 for ; Wed, 3 Dec 2025 21:28:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.208 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764797306; cv=none; b=tKoW0w7aiJXp+J9ngnqWQFLdmdaTRBhiRcuTe1/dvhZIkHQ0h9sxepwCjiLFRRigKuySH0USe2RATP/phgvcQdsDEMSJnBVPFXKZkMFKQHF2Crfvg22Z9zL2VdzVvTixsSD7J26WqNxgDkcYrjFBeSURve1nENzgVOVQ8Y1IKVE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764797306; c=relaxed/simple; bh=f+K+aX/mNBZb+LG8JROmAZQAidoAsW+ASV4BgI9gvbo=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=evDpugToYEFM1uPs8tndM9eMVi0f+QRk1wyxSbdMmK5ddshyYlKUEZvUmMY0snh3Baq/9nOVtmh+Kfv40i448is9FaFZSRXTModVNwQyxkxRCtozdp9rUVirSanluuRV5s296XIIxXnSQCUEJ2W/xMRfXSiSkXtbr1BjwkfIh+A= 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=209.85.167.208 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-oi1-f208.google.com with SMTP id 5614622812f47-4510650af52so262480b6e.3 for ; Wed, 03 Dec 2025 13:28:23 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764797303; x=1765402103; 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=1dZlUS5HZ27P8V3O7na3VnTbdQVdrVSsz2kOKYSMpJM=; b=iq0aWVAYs4Sb1Jx5r/X++pD6VQw/CvXywAukc/67Gn6WEPNZ2GCqz6tLoQ+b4YcG45 MSZc47KPZWXeR5wcX3Qa7I/XIPP5zYiI5qSwj11DQfbeBEPLH7uCjJCK7ZNF3mJfHbfB tQOY0xprgWS+kNG4cMHNbF9pSOTmjaL4tgfoAuXoPoSN8w15uQTUh+TrwpUQVggZQJl9 N0C/nPahAJ8O8lwwvyIX5HsAO3A/aE/xLOhaAuK3UTo6FDK54MCoDpxDHOE2THN4Tqcb TBF3PScXqewp/Q16EJ8jA7q6dgBapPoL1+D8DaLAef9wpnYVrtSBbfqdNCL3HPafaFUs 8cXQ== X-Forwarded-Encrypted: i=1; AJvYcCW1dGR10g+RbxFW3o2TJS0DFELlxHyZ9bmfsa7APGsrkrl9XoMH8AcFirwQxcmWJ+fgw4F7jEgZd+za6g==@vger.kernel.org X-Gm-Message-State: AOJu0YxsQ/6eapg65v8IODBcwmgaU3CCS4j8DC/oDS9b06nYFffhyebi Og0LeI5+n4tMyo7D27NNTa0sJ5jOcMB92W0t/myHKlvR6Su7yJFDfttJBNTk/zPTjycpCxavrUn LB7cuY4ArYKty7gsggeTd/y2AYngVTe0HYkaw45oRbv/+UmCOEJ+GXsWUxJo= X-Google-Smtp-Source: AGHT+IHuuOng1zmi6ftbhBwdcHCse0fRadUnYIQlAovoDUEWD84+PjonPKDcCUKMhrWrnj2/hSVLJJoqxG1c7GeCCDOII2xr74Ye Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:2216:b0:450:275c:87d8 with SMTP id 5614622812f47-45379e492demr300558b6e.32.1764797302965; Wed, 03 Dec 2025 13:28:22 -0800 (PST) Date: Wed, 03 Dec 2025 13:28:22 -0800 In-Reply-To: <000000000000cf2c4c061ee07a3d@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6930ab76.a70a0220.d98e3.01ba.GAE@google.com> Subject: Re: [syzbot] [block?] INFO: task hung in read_part_sector (2) From: syzbot To: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 4de44542991e Merge git://git.kernel.org/pub/scm/linux/kern.. git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=1525f512580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6d0b6a854526a37e dashboard link: https://syzkaller.appspot.com/bug?extid=82de77d3f217960f087d 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=1764d4c2580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/780f42d09193/disk-4de44542.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/953583251b3f/vmlinux-4de44542.xz kernel image: https://storage.googleapis.com/syzbot-assets/0cbf55634459/bzImage-4de44542.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+82de77d3f217960f087d@syzkaller.appspotmail.com INFO: task udevd:5881 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:21736 pid:5881 tgid:5881 ppid:5195 task_flags:0x400140 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 io_schedule+0x80/0xd0 kernel/sched/core.c:7871 folio_wait_bit_common+0x6b0/0xb80 mm/filemap.c:1330 folio_put_wait_locked mm/filemap.c:1494 [inline] do_read_cache_folio+0x1aa/0x590 mm/filemap.c:4019 read_mapping_folio include/linux/pagemap.h:999 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:722 adfspart_check_POWERTEC+0x8c/0xf30 block/partitions/acorn.c:454 check_partition block/partitions/core.c:141 [inline] blk_add_partitions block/partitions/core.c:589 [inline] bdev_disk_changed+0x75f/0x14b0 block/partitions/core.c:693 blkdev_get_whole+0x380/0x510 block/bdev.c:748 bdev_open+0x31e/0xd30 block/bdev.c:957 blkdev_open+0x457/0x600 block/fops.c:701 do_dentry_open+0x953/0x13f0 fs/open.c:965 vfs_open+0x3b/0x340 fs/open.c:1097 do_open fs/namei.c:3975 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4134 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 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: 0033:0x7f4c282a7407 RSP: 002b:00007ffdb4725950 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f4c2895a880 RCX: 00007f4c282a7407 RDX: 00000000000a0800 RSI: 00005636cc3d6810 RDI: ffffffffffffff9c RBP: 00005636cc376910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00005636cc38b830 R13: 00005636cc384190 R14: 0000000000000000 R15: 00005636cc38b830 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 1 lock held by klogd/5184: #0: ffff8880b883a218 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638 2 locks held by getty/5586: #0: ffff88803332b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by udevd/5881: #0: ffff888144370358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945 2 locks held by dhcpcd/28194: #0: ffff88807a754260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline] #0: ffff88807a754260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3197 #1: ffffffff8df43178 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #1: ffffffff8df43178 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957 2 locks held by syz.0.10501/28195: #0: ffff888060739908 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline] #0: ffff888060739908 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release net/socket.c:661 [inline] #0: ffff888060739908 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1455 #1: ffffffff8df43178 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #1: ffffffff8df43178 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 28198 Comm: syz.0.10502 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400 Code: e8 3e 09 ab fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 cf cc 10 fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07 RSP: 0018:ffffc9000dc5eb70 EFLAGS: 00000002 RAX: 1ffffffff335f300 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffffff99afa1d0 R08: ffff888143300237 R09: 1ffff11028660046 R10: dffffc0000000000 R11: ffffffff8514fa20 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff99af9f40 R15: 0000000000000000 FS: 00007f3e13a0b6c0(0000) GS:ffff88812612e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001ac0 CR3: 000000001b6d8000 CR4: 00000000003526f0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:137 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline] wait_for_lsr+0x1a1/0x2f0 drivers/tty/serial/8250/8250_port.c:1961 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline] serial8250_console_write+0x134c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3111 [inline] console_flush_all+0x6f3/0xb10 kernel/printk/printk.c:3199 __console_flush_and_unlock kernel/printk/printk.c:3258 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3298 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423 _printk+0xcf/0x120 kernel/printk/printk.c:2448 nbd_genl_connect+0x9b0/0x18f0 drivers/block/nbd.c:2141 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x830 net/socket.c:2630 ___sys_sendmsg+0x21f/0x2a0 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+0x19b/0x260 net/socket.c:2719 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: 0033:0x7f3e12b8f749 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:00007f3e13a0b038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f3e12de5fa0 RCX: 00007f3e12b8f749 RDX: 0000000020000000 RSI: 0000200000001ac0 RDI: 0000000000000005 RBP: 00007f3e12c13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3e12de6038 R14: 00007f3e12de5fa0 R15: 00007fff079ed2f8 --- 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.