From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f72.google.com (mail-oa1-f72.google.com [209.85.160.72]) (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 DA1D030F95A for ; Wed, 11 Feb 2026 16:37:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.72 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770827848; cv=none; b=GX3kM4ILnXQ0/Oeh4X1Ap+xpW2DoaxrIoR6dr5KlbQqikEGyD8jXKm56D8WZ0JndAChXiMSs8IE23I02i256tQG3RCgVYtyJHIkD3SVU26mNpOLU3Cu0DNwTjke63E2+mS9myCoGWr8FX4M9p6oJDNAxY5WQ67+5yAHjHB7ETTA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770827848; c=relaxed/simple; bh=jorlHSRmS7/xt7i4l4Pyghks1Pvdlk0GEZ4CUANMrdY=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=rWKvAjAdsATckxSyJkx4GWXEBmsBVrwuvVLAeqdnXNqW0QaxOA/KZN4wxFT9mZVcSgWhOCwtSN4xozB4BwmcwxZ17rFm5F+S827e73OrFVUkOOLJYMi2N4ZTqQ61OJtH/YoXe/wpctCBpjKm1Fd8yPxtt7UylmHNV4YA7b5Kpgo= 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=209.85.160.72 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-oa1-f72.google.com with SMTP id 586e51a60fabf-409e0cc22c6so5825548fac.0 for ; Wed, 11 Feb 2026 08:37:26 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770827846; x=1771432646; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=exeiSYntXVdj6w0wteLjMpe8skF48q4LTcb+YxISNVc=; b=YKeHpG8A1c1UFcPMLUpSnHJOYW2/lEiJBFYbSBbE3m2/Z6xUjpUbN+VnIZA2urVGAV dI31AAjgmdSGMPcAgNxUsReG94ScMu7S0kdS/o02Q9UQyyjwJZbPZPIeK4x26CL3wJG4 pprNoff+rIn5Sc2VKBAM4aq9h9jjmhBdK8SHv62MSPzLWgZwPzWQXzi5eOsvuhaxXt/Z kJa8p53OFxlIbYiaUyfeE6Yf0hZGspSXaElIVprqZGyPdoX1+0TNs+GnjLzlexxet3YZ na9cPU/+gwMzq+JFj9cUMWO4Ja/XPrYlmm4U5F2bxocg44RkeC5EfrbuIStSMThoRJ2q 66yw== X-Forwarded-Encrypted: i=1; AJvYcCXo2fd+hHwz/wa5r/0yZdtXVHylL174AkAcXcUDEIpHLb3PsjBfptB/Q13a3qVvTjHZJsCZLZnYVio7740=@vger.kernel.org X-Gm-Message-State: AOJu0YwFKmOCNi6d4+pwCbaps7lKuPi/jLcpbRzxehwhqJaY7y0T/Qu2 J1zsbdxsnJUSkFHIdfzHUhME/be/s+71lVIkHaDdU8+Yyt0x0gJfy8StPWji/sID0YzSYHTYnGs 6T2rq2JBluol4WDbLNSHX595+mwP+E5NT4G8XTzBVRdW4Q4dCOhf9PMqjD5I= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:61a:b0:66a:bd71:f058 with SMTP id 006d021491bc7-672e61d6c5dmr3339679eaf.28.1770827845731; Wed, 11 Feb 2026 08:37:25 -0800 (PST) Date: Wed, 11 Feb 2026 08:37:25 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <698cb045.050a0220.2eeac1.009b.GAE@google.com> Subject: [syzbot] [ext4?] INFO: task hung in block_read_full_folio (3) From: syzbot To: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 2687c848e578 x86/vmware: Fix hypercall clobbers git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=158c2a5a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=e3161cabe5a361ff dashboard link: https://syzkaller.appspot.com/bug?extid=03afbb29537f0336b7ad compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=131aab22580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/988f106eda78/disk-2687c848.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/52aad858e7e7/vmlinux-2687c848.xz kernel image: https://storage.googleapis.com/syzbot-assets/99f1cbe5967b/bzImage-2687c848.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/405f0d179069/mount_0.gz fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=16a9265a580000) IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+03afbb29537f0336b7ad@syzkaller.appspotmail.com INFO: task syz.3.1794:12741 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.1794 state:D stack:23768 pid:12741 tgid:12736 ppid:5962 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 io_schedule+0x7f/0xd0 kernel/sched/core.c:7791 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250 __wait_on_bit_lock+0xec/0x4e0 kernel/sched/wait_bit.c:93 out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120 wait_on_bit_lock_io include/linux/wait_bit.h:221 [inline] __lock_buffer fs/buffer.c:71 [inline] lock_buffer include/linux/buffer_head.h:432 [inline] block_read_full_folio+0x38f/0x830 fs/buffer.c:2439 filemap_read_folio+0x137/0x3b0 mm/filemap.c:2496 do_read_cache_folio+0x358/0x590 mm/filemap.c:4096 read_mapping_folio include/linux/pagemap.h:1028 [inline] read_part_sector+0xb6/0x2b0 block/partitions/core.c:722 amiga_partition+0xe0/0x1dd0 block/partitions/amiga.c:53 check_partition block/partitions/core.c:141 [inline] blk_add_partitions block/partitions/core.c:589 [inline] bdev_disk_changed+0x765/0x14c0 block/partitions/core.c:693 loop_reread_partitions drivers/block/loop.c:448 [inline] loop_set_status+0x9ab/0xe40 drivers/block/loop.c:1277 loop_set_status64 drivers/block/loop.c:1373 [inline] lo_ioctl+0xc21/0x1fb0 drivers/block/loop.c:1559 blkdev_ioctl+0x5e3/0x740 block/ioctl.c:792 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0918d9aeb9 RSP: 002b:00007f0919c77028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f0919015fa0 RCX: 00007f0918d9aeb9 RDX: 00002000000003c0 RSI: 0000000000004c04 RDI: 0000000000000005 RBP: 00007f0918e08c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0919016038 R14: 00007f0919015fa0 R15: 00007ffe22744b08 INFO: task syz.3.1794:12749 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.1794 state:D stack:22936 pid:12749 tgid:12736 ppid:5962 task_flags:0x440140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 io_schedule+0x7f/0xd0 kernel/sched/core.c:7791 folio_wait_bit_common+0x6d8/0xbc0 mm/filemap.c:1323 folio_lock include/linux/pagemap.h:1170 [inline] __find_get_block_slow fs/buffer.c:205 [inline] find_get_block_common+0x23c/0xe60 fs/buffer.c:1408 bdev_getblk+0x53/0x6e0 include/linux/gfp.h:-1 __getblk include/linux/buffer_head.h:380 [inline] sb_getblk include/linux/buffer_head.h:386 [inline] __ext4_get_inode_loc+0x7d8/0xfa0 fs/ext4/inode.c:4860 ext4_get_inode_loc fs/ext4/inode.c:4963 [inline] ext4_reserve_inode_write+0x18b/0x360 fs/ext4/inode.c:6287 __ext4_mark_inode_dirty+0x14b/0x6e0 fs/ext4/inode.c:6465 ext4_ext_insert_extent+0x2062/0x4b50 fs/ext4/extents.c:2192 ext4_ext_map_blocks+0x19d1/0x6b80 fs/ext4/extents.c:4404 ext4_map_create_blocks fs/ext4/inode.c:613 [inline] ext4_map_blocks+0x8da/0x1830 fs/ext4/inode.c:816 ext4_getblk+0x1ca/0x780 fs/ext4/inode.c:984 ext4_bread+0x2a/0x180 fs/ext4/inode.c:1047 ext4_quota_write+0x239/0x580 fs/ext4/super.c:7350 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x368/0x720 fs/quota/quota_tree.c:136 do_insert_tree+0x256/0x11d0 fs/quota/quota_tree.c:347 do_insert_tree+0x9d7/0x11d0 fs/quota/quota_tree.c:402 do_insert_tree+0x9b2/0x11d0 fs/quota/quota_tree.c:402 do_insert_tree+0x9b2/0x11d0 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x4b1/0x5e0 fs/quota/quota_tree.c:451 v2_write_dquot+0x183/0x260 fs/quota/quota_v2.c:372 dquot_acquire+0x328/0x620 fs/quota/dquot.c:473 ext4_acquire_dquot+0x2e9/0x4c0 fs/ext4/super.c:6982 dqget+0x7b1/0xf10 fs/quota/dquot.c:980 __dquot_initialize+0x3ba/0xd30 fs/quota/dquot.c:1508 ext4_xattr_set+0xdb/0x340 fs/ext4/xattr.c:2543 __vfs_setxattr+0x43c/0x480 fs/xattr.c:200 __vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234 vfs_setxattr+0x16a/0x2e0 fs/xattr.c:321 do_setxattr fs/xattr.c:636 [inline] filename_setxattr+0x281/0x630 fs/xattr.c:665 path_setxattrat+0x3f3/0x430 fs/xattr.c:713 __do_sys_lsetxattr fs/xattr.c:754 [inline] __se_sys_lsetxattr fs/xattr.c:750 [inline] __x64_sys_lsetxattr+0xbf/0xe0 fs/xattr.c:750 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0918d9aeb9 RSP: 002b:00007f0919c56028 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd RAX: ffffffffffffffda RBX: 00007f0919016090 RCX: 00007f0918d9aeb9 RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000200000000180 RBP: 00007f0918e08c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0919016128 R14: 00007f0919016090 R15: 00007ffe22744b08 Showing all locks held in the system: 1 lock held by khungtaskd/32: #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by udevd/5187: #0: ffff8881423cc358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 #1: ffff8881423cb448 ( &lo->lo_mutex ){+.+.}-{4:4}, at: lo_open+0x4f/0xd0 drivers/block/loop.c:1721 2 locks held by getty/5574: #0: ffff88814e76c0a0 (&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+0x45c/0x13c0 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/5970: #0: ffffffff8e560c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #0: ffffffff8e560c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:956 1 lock held by udevd/10512: #0: ffff8881423cc358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 1 lock held by udevd/10515: #0: ffff888148c4e3a8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline] #0: ffff888148c4e3a8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:855 1 lock held by syz.3.1794/12741: #0: ffff8880247da358 (&disk->open_mutex){+.+.}-{4:4}, at: loop_reread_partitions drivers/block/loop.c:447 [inline] #0: ffff8880247da358 (&disk->open_mutex){+.+.}-{4:4}, at: loop_set_status+0x986/0xe40 drivers/block/loop.c:1277 5 locks held by syz.3.1794/12749: #0: ffff888031f7e420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff888060996420 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff888060996420 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x143/0x2e0 fs/xattr.c:320 #2: ffff88805edd7228 (&dquot->dq_lock){+.+.}-{4:4}, at: dquot_acquire+0x67/0x620 fs/quota/dquot.c:461 #3: ffff888031f7e208 (&s->s_dquot.dqio_sem){++++}-{4:4}, at: v2_write_dquot+0xab/0x260 fs/quota/quota_v2.c:367 #4: ffff888060990c10 (&ei->i_data_sem/2){++++}-{4:4}, at: ext4_map_blocks+0x7d7/0x1830 fs/ext4/inode.c:815 2 locks held by ext4lazyinit/15775: #0: ffff88805aa420e0 (&type->s_umount_key#31){++++}-{4:4}, at: ext4_lazyinit_thread+0x1b7/0x1830 fs/ext4/super.c:3818 #1: ffff88805aa42420 (sb_writers#4){.+.+}-{0:0}, at: kthread+0x726/0x8b0 kernel/kthread.c:463 3 locks held by syz.1.3370/18614: #0: ffff8881423cb448 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0xc3/0xe40 drivers/block/loop.c:1235 #1: ffff888142392680 (&q->q_usage_counter(io)#18){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline] #1: ffff888142392680 (&q->q_usage_counter(io)#18){++++}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251 #2: ffff8881423926b8 (&q->q_usage_counter(queue)#2){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline] #2: ffff8881423926b8 (&q->q_usage_counter(queue)#2){+.+.}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251 4 locks held by syz.1.3370/18624: #0: ffff88805aa42420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88807863a0c0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff88807863a0c0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x143/0x2e0 fs/xattr.c:320 #2: ffff8880785a2968 (&dquot->dq_lock){+.+.}-{4:4}, at: dquot_acquire+0x67/0x620 fs/quota/dquot.c:461 #3: ffff88805aa42208 (&s->s_dquot.dqio_sem){++++}-{4:4}, at: v2_read_dquot+0x50/0x1d0 fs/quota/quota_v2.c:342 3 locks held by syz.0.3371/18615: #0: ffff8881423c8448 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0xc3/0xe40 drivers/block/loop.c:1235 #1: ffff888142391cf8 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline] #1: ffff888142391cf8 (&q->q_usage_counter(io)#17){++++}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251 #2: ffff888142391d30 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline] #2: ffff888142391d30 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251 4 locks held by syz.0.3371/18626: #0: ffff88803381c420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff8880786920c0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff8880786920c0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x143/0x2e0 fs/xattr.c:320 #2: ffff8880785a3ca8 (&dquot->dq_lock){+.+.}-{4:4}, at: dquot_acquire+0x67/0x620 fs/quota/dquot.c:461 #3: ffff88803381c208 (&s->s_dquot.dqio_sem){++++}-{4:4}, at: v2_read_dquot+0x50/0x1d0 fs/quota/quota_v2.c:342 3 locks held by syz.4.3374/18631: #0: ffff8880247dc448 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_set_status+0xc3/0xe40 drivers/block/loop.c:1235 #1: ffff888142394318 (&q->q_usage_counter(io)#21){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline] #1: ffff888142394318 (&q->q_usage_counter(io)#21){++++}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251 #2: ffff888142394350 (&q->q_usage_counter(queue)#5){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:954 [inline] #2: ffff888142394350 (&q->q_usage_counter(queue)#5){+.+.}-{0:0}, at: loop_set_status+0x310/0xe40 drivers/block/loop.c:1251 4 locks held by syz.4.3374/18633: #0: ffff88805e0e8420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88807863e420 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff88807863e420 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x143/0x2e0 fs/xattr.c:320 #2: ffff8880785a33e8 (&dquot->dq_lock){+.+.}-{4:4}, at: dquot_acquire+0x67/0x620 fs/quota/dquot.c:461 #3: ffff88805e0e8208 (&s->s_dquot.dqio_sem){++++}-{4:4}, at: v2_read_dquot+0x50/0x1d0 fs/quota/quota_v2.c:342 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 18624 Comm: syz.1.3370 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400 Code: e8 ae ae 92 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 4f fe fa fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 65 75 de fb cc 44 89 f9 80 e1 07 RSP: 0018:ffffc9000ce6ebf0 EFLAGS: 00000002 RAX: 1ffffffff3467000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffffff9a338530 R08: ffff8881482f0237 R09: 1ffff1102905e046 R10: dffffc0000000000 R11: ffffffff8531cb20 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff9a3382a0 R15: 0000000000000000 FS: 00007fc4d59d56c0(0000) GS:ffff8881256f3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0ae19e8600 CR3: 00000000527fe000 CR4: 0000000000350ef0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:128 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:150 [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+0x1348/0x1ba0 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3129 [inline] console_flush_one_record kernel/printk/printk.c:3215 [inline] console_flush_all+0x718/0xb20 kernel/printk/printk.c:3289 __console_flush_and_unlock kernel/printk/printk.c:3319 [inline] console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3359 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2426 _printk+0xdd/0x130 kernel/printk/printk.c:2451 __quota_error+0x1a6/0x1d0 fs/quota/dquot.c:148 write_blk fs/quota/quota_tree.c:73 [inline] get_free_dqblk+0x3cd/0x720 fs/quota/quota_tree.c:136 do_insert_tree+0x256/0x11d0 fs/quota/quota_tree.c:347 do_insert_tree+0x9d7/0x11d0 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x4b1/0x5e0 fs/quota/quota_tree.c:451 v2_write_dquot+0x183/0x260 fs/quota/quota_v2.c:372 dquot_acquire+0x328/0x620 fs/quota/dquot.c:473 ext4_acquire_dquot+0x2e9/0x4c0 fs/ext4/super.c:6982 dqget+0x7b1/0xf10 fs/quota/dquot.c:980 __dquot_initialize+0x3ba/0xd30 fs/quota/dquot.c:1508 ext4_xattr_set+0xdb/0x340 fs/ext4/xattr.c:2543 __vfs_setxattr+0x43c/0x480 fs/xattr.c:200 __vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234 vfs_setxattr+0x16a/0x2e0 fs/xattr.c:321 do_setxattr fs/xattr.c:636 [inline] filename_setxattr+0x281/0x630 fs/xattr.c:665 path_setxattrat+0x3f3/0x430 fs/xattr.c:713 __do_sys_lsetxattr fs/xattr.c:754 [inline] __se_sys_lsetxattr fs/xattr.c:750 [inline] __x64_sys_lsetxattr+0xbf/0xe0 fs/xattr.c:750 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc4d639aeb9 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:00007fc4d59d5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd RAX: ffffffffffffffda RBX: 00007fc4d6616090 RCX: 00007fc4d639aeb9 RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000200000000180 RBP: 00007fc4d6408c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc4d6616128 R14: 00007fc4d6616090 R15: 00007ffed7e83f48 --- 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