From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f78.google.com (mail-oo1-f78.google.com [209.85.161.78]) (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 D7E7C2F617C for ; Fri, 1 May 2026 14:48:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777646905; cv=none; b=M2eUQXUwgC16ryf0pmCYJa3ynj/p27iZnjb+Hl2Q47TBBHgYnFuadyq/45RzVYAwKav+/SWaiPtG7v3x7vwIDzYTeC2orA9ToyQLQcqzDQ/7DndMj/8tMg+sMZVv1iPEe5qbYjZTnkKxnOPVUxCk2zaB/Q+Ofs2KysiP3njT9Ec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777646905; c=relaxed/simple; bh=iCn4il1+fR+xhzdRDO4/0pduJ++ArORnInOJYPi5JNo=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=XGyoDYLKd4s43l3+j41ismZ9ceBwZjWVCsF92htg5CgEtCAyppTrGKiUzecy5gkEzHYuJCY0TWa8Eufbo1mrvm012Grzsi0dk345rvIwGhUFu/Ug0SMdBeucZ+0i335BKHYrMp1udWaFSFP9vadoBwSK2L9t/cn5gtXOyrM/mEg= 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=209.85.161.78 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-f78.google.com with SMTP id 006d021491bc7-6948d83a548so5588418eaf.0 for ; Fri, 01 May 2026 07:48:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777646903; x=1778251703; 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=Y2JCmLeyeweVZ2HOndzR/fDb+J2Pz8pUafUEVYUwBkY=; b=YWMoZxMUuUER0pTd4+iPYQDjoQvX65Fj2R7kL0b2l5xtELn415OyVwwqkBtXmiN+Gq 8q4SLrzyJwvigncDt/+3nMiQGFbykvEiw8BemVB9tPrRUMou8GwRMLyX1xcQzY6/LIca cwM/uVsWaRfMtort9+iuCpydbHKkTUEn7A52oDgtvJz1RrVWjz7h4GehrIy4CGIbi7dI JppJyvH5QEArGoG5AJUeQfRzlAd0lzqXxOCBPRCzM0Xeu9KSXFUtfmk4JIN5R9TYTL4z WRx4r+vtD8qD6JJapx8w7s+BCzLyQYRyDceY/2Qr+tGTumf5/wt3TB0Y4HmCiIWgOAs8 rVBw== X-Forwarded-Encrypted: i=1; AFNElJ/tf8Sbbdc9UbWxT536Tf+QsR0iNrABTuh18CIkWUc6Ny0oTLJDGa2kUCVuXuD6Uj+uFBFkSntoN5PT@vger.kernel.org X-Gm-Message-State: AOJu0YzWr8xjklh/LQb7Uv68EKhjvZzk3jMRJnQKRjDyIJX0cBuD29sO tzFKR5FkzNu7VokYE8ksJQ2XrrBBpPnP/pYGSwuepIOaXQH021bRrpHAd0EEzaOCC1a6R8W5Y3S QvzmjDItZkBYhvJdD8NXJTHHDs7X4rNIB4vGwbDT7QDyx76ekPw7x5JGj9rg= Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2912:b0:696:18a4:87c2 with SMTP id 006d021491bc7-6967a529815mr4068872eaf.25.1777646902830; Fri, 01 May 2026 07:48:22 -0700 (PDT) Date: Fri, 01 May 2026 07:48:22 -0700 In-Reply-To: <69f3f165.170a0220.5f1b.0010.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69f4bd36.050a0220.312cd3.0013.GAE@google.com> Subject: Re: [syzbot] [ext4?] INFO: task jbd2/sda1-NUM:NUM blocked in I/O wait for more than NUM seconds. From: syzbot To: jack@suse.com, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 26fd6bff2c05 Merge tag 'mtd/fixes-for-7.1-rc2' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1229bece580000 kernel config: https://syzkaller.appspot.com/x/.config?x=d0f0911eedbc130a dashboard link: https://syzkaller.appspot.com/bug?extid=c7604c9fdd7580cca4e0 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17f37506580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=171441ce580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/7d72741f9879/disk-26fd6bff.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/b02c6a1eba87/vmlinux-26fd6bff.xz kernel image: https://storage.googleapis.com/syzbot-assets/4f218b09b68f/bzImage-26fd6bff.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c7604c9fdd7580cca4e0@syzkaller.appspotmail.com INFO: task jbd2/sda1-8:4955 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:jbd2/sda1-8 state:D stack:26088 pid:4955 tgid:4955 ppid:2 task_flags:0x240040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 io_schedule+0x8a/0xf0 kernel/sched/core.c:8109 bit_wait_io+0xd/0xe0 kernel/sched/wait_bit.c:250 __wait_on_bit+0x65/0x180 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0xdc/0x110 kernel/sched/wait_bit.c:67 wait_on_bit_io include/linux/wait_bit.h:105 [inline] __wait_on_buffer+0x64/0x70 fs/buffer.c:123 wait_on_buffer include/linux/buffer_head.h:420 [inline] jbd2_journal_commit_transaction+0x388a/0x6870 fs/jbd2/commit.c:837 kjournald2+0x200/0x760 fs/jbd2/journal.c:201 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: task syz.0.189:6070 blocked in I/O wait for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.189 state:D stack:28240 pid:6070 tgid:6070 ppid:5783 task_flags:0x440040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 io_schedule+0x8a/0xf0 kernel/sched/core.c:8109 bit_wait_io+0xd/0xe0 kernel/sched/wait_bit.c:250 __wait_on_bit+0x65/0x180 kernel/sched/wait_bit.c:52 out_of_line_wait_on_bit+0xdc/0x110 kernel/sched/wait_bit.c:67 wait_on_bit_io include/linux/wait_bit.h:105 [inline] do_get_write_access+0x84f/0x1220 fs/jbd2/transaction.c:1113 jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1263 __ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:241 ext4_reserve_inode_write+0x1b7/0x330 fs/ext4/inode.c:6375 __ext4_mark_inode_dirty+0x18f/0x890 fs/ext4/inode.c:6550 ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6587 __mark_inode_dirty+0x1f3/0x1720 fs/fs-writeback.c:2623 generic_update_time fs/inode.c:2192 [inline] file_update_time_flags+0x46b/0x500 fs/inode.c:2422 ext4_page_mkwrite+0x324/0x1890 fs/ext4/inode.c:6753 do_page_mkwrite+0x17a/0x440 mm/memory.c:3668 do_shared_fault mm/memory.c:5969 [inline] do_fault+0x3b5/0x1750 mm/memory.c:6031 do_pte_missing mm/memory.c:4550 [inline] handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault+0x187d/0x2a00 mm/memory.c:6549 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718 do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f97a466a883 RSP: 002b:00007ffc3f813c60 EFLAGS: 00010246 RAX: 000000000003fde8 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000001b2e124000 RSI: 0000000000040000 RDI: 00007f97a49db710 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffc3f813ef0 Showing all locks held in the system: 1 lock held by ksoftirqd/1/23: #0: ffff8880b853b3e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x140 kernel/sched/core.c:652 1 lock held by khungtaskd/30: #0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 6 locks held by kworker/u8:3/47: #0: ffff88801c6ca140 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc90000b77d08 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff8880389060d8 (&type->s_umount_key#33){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:565 #3: ffff888038904c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x278/0x600 mm/page-writeback.c:2575 #4: ffff888038902938 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfaa/0x13a0 fs/jbd2/transaction.c:444 #5: ffff88807928f290 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x45a/0xd30 fs/ext4/inode.c:823 2 locks held by getty/5383: #0: ffff88802dace0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14f0 drivers/tty/n_tty.c:2211 3 locks held by syz.0.189/6070: #0: ffff88807e006bc8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x11d/0x590 mm/mmap_lock.c:310 #1: ffff888038906508 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x17a/0x440 mm/memory.c:3668 #2: ffff888038902938 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfaa/0x13a0 fs/jbd2/transaction.c:444 3 locks held by syz-executor/6077: #0: ffff888038906410 (sb_writers#4){.+.+}-{0:0}, at: filename_create+0x10d/0x400 fs/namei.c:4943 #1: ffff8880792b1f98 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline] #1: ffff8880792b1f98 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2914 [inline] #1: ffff8880792b1f98 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2938 [inline] #1: ffff8880792b1f98 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x1c0/0x400 fs/namei.c:4950 #2: ffff888038902938 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfaa/0x13a0 fs/jbd2/transaction.c:444 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xcb1/0x1030 kernel/hung_task.c:561 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 1057 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:smp_call_function_many_cond+0xdd4/0x1700 kernel/smp.c:871 Code: 00 00 0f 84 1e 05 00 00 e8 c9 6a 0c 00 83 c5 01 bf 07 00 00 00 48 63 dd 48 89 de e8 96 65 0c 00 48 83 fb 07 0f 86 22 fb ff ff <44> 8b 64 24 58 44 8b 7c 24 5c e8 9d 6a 0c 00 8b 5c 24 4c bf 01 00 RSP: 0018:ffffc90003d37870 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fb686f RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888029b83d80 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90003d37958 R13: ffff8880b843c6c0 R14: ffff8880b843c601 R15: ffff8880b853c710 FS: 0000000000000000(0000) GS:ffff88812447d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055a400fed660 CR3: 000000000e596000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x976/0xc60 arch/x86/kernel/alternative.c:3045 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:906 [inline] toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:898 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 0f 84 1e 05 00 00 je 0x526 8: e8 c9 6a 0c 00 call 0xc6ad6 d: 83 c5 01 add $0x1,%ebp 10: bf 07 00 00 00 mov $0x7,%edi 15: 48 63 dd movslq %ebp,%rbx 18: 48 89 de mov %rbx,%rsi 1b: e8 96 65 0c 00 call 0xc65b6 20: 48 83 fb 07 cmp $0x7,%rbx 24: 0f 86 22 fb ff ff jbe 0xfffffb4c * 2a: 44 8b 64 24 58 mov 0x58(%rsp),%r12d <-- trapping instruction 2f: 44 8b 7c 24 5c mov 0x5c(%rsp),%r15d 34: e8 9d 6a 0c 00 call 0xc6ad6 39: 8b 5c 24 4c mov 0x4c(%rsp),%ebx 3d: bf .byte 0xbf 3e: 01 00 add %eax,(%rax) --- 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.