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Message-ID: <69bafc73-d147-4e7d-939d-4b99e68e0678@kernel.org> Date: Sat, 23 Aug 2025 16:44:58 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Hillf Danton References: <20250822222346.5267-1-hdanton@sina.com> Content-Language: en-US In-Reply-To: <20250822222346.5267-1-hdanton@sina.com> X-Headers-End: 1upjs3-0001Ou-9g Subject: Re: [f2fs-dev] [syzbot] [f2fs?] INFO: task hung in f2fs_llseek X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Chao Yu via Linux-f2fs-devel Reply-To: Chao Yu Cc: syzkaller-bugs@googlegroups.com, syzbot , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On 8/23/2025 6:23 AM, Hillf Danton wrote: >> Date: Fri, 22 Aug 2025 11:56:27 -0700 >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: 3957a5720157 Merge tag 'cgroup-for-6.17-rc2-fixes' of git:.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=13e20c42580000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=e1e1566c7726877e >> dashboard link: https://syzkaller.appspot.com/bug?extid=942fb6ce3ac2843a1420 >> compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17db07bc580000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f62a34580000 >> >> Downloadable assets: >> disk image: https://storage.googleapis.com/syzbot-assets/c5cbe8650b9a/disk-3957a572.raw.xz >> vmlinux: https://storage.googleapis.com/syzbot-assets/51911bea9855/vmlinux-3957a572.xz >> kernel image: https://storage.googleapis.com/syzbot-assets/b07279b5fcc2/bzImage-3957a572.xz >> mounted in repro: https://storage.googleapis.com/syzbot-assets/f35e0e9a079a/mount_0.gz >> fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=10a5dfa2580000) >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+942fb6ce3ac2843a1420@syzkaller.appspotmail.com >> >> INFO: task syz.1.23:6086 blocked for more than 143 seconds. >> Tainted: G W syzkaller #0 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> task:syz.1.23 state:D stack:29352 pid:6086 tgid:6081 ppid:6062 task_flags:0x400040 flags:0x00004004 >> Call Trace: >> >> context_switch kernel/sched/core.c:5357 [inline] >> __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 >> __schedule_loop kernel/sched/core.c:7043 [inline] >> rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 >> rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] >> __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] >> __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 >> __rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114 >> rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] >> __down_read kernel/locking/rwsem.c:1466 [inline] >> down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539 >> inode_lock_shared include/linux/fs.h:884 [inline] >> f2fs_seek_block fs/f2fs/file.c:458 [inline] >> f2fs_llseek+0x1e5/0x1840 fs/f2fs/file.c:545 >> vfs_llseek fs/read_write.c:389 [inline] >> ksys_lseek fs/read_write.c:402 [inline] >> __do_sys_lseek fs/read_write.c:412 [inline] >> __se_sys_lseek fs/read_write.c:410 [inline] >> __x64_sys_lseek+0x155/0x1f0 fs/read_write.c:410 >> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] >> do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 >> entry_SYSCALL_64_after_hwframe+0x77/0x7f >> RIP: 0033:0x7f7c9077ebe9 >> RSP: 002b:00007f7c8fdcd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000008 >> RAX: ffffffffffffffda RBX: 00007f7c909a6090 RCX: 00007f7c9077ebe9 >> RDX: 0000000000000004 RSI: 0000000000000008 RDI: 0000000000000004 >> RBP: 00007f7c90801e19 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 >> R13: 00007f7c909a6128 R14: 00007f7c909a6090 R15: 00007fffeb5fe138 >> >> INFO: lockdep is turned off. >> NMI backtrace for cpu 1 >> CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Tainted: G W syzkaller #0 PREEMPT_{RT,(full)} >> Tainted: [W]=WARN >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 >> 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:328 [inline] >> watchdog+0xf93/0xfe0 kernel/hung_task.c:491 >> kthread+0x70e/0x8a0 kernel/kthread.c:463 >> ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 >> 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: 6274 Comm: syz.3.43 Tainted: G W syzkaller #0 PREEMPT_{RT,(full)} >> Tainted: [W]=WARN >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 >> RIP: 0010:unwind_next_frame+0x175d/0x2390 arch/x86/kernel/unwind_orc.c:648 >> Code: 28 84 c0 0f 85 19 0b 00 00 48 89 d0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 2b 0b 00 00 48 0f bf 03 49 01 c4 49 8d 56 40 4c 89 f7 <4c> 89 e6 eb 5d 49 8d 5e 40 48 89 d8 48 c1 e8 03 80 3c 28 00 74 08 >> RSP: 0018:ffffc90003b06438 EFLAGS: 00000283 >> RAX: fffffffffffffff0 RBX: ffffffff8fd32106 RCX: 0000000000000000 >> RDX: ffffc90003b06548 RSI: 0000000000000001 RDI: ffffc90003b06508 >> RBP: dffffc0000000000 R08: ffffc90003b06567 R09: 0000000000000000 >> R10: ffffc90003b06558 R11: fffff52000760cad R12: ffffc90003b069d0 >> R13: ffffc90003b06558 R14: ffffc90003b06508 R15: 1ffffffff1fa6421 >> FS: 00007f0008c3c6c0(0000) GS:ffff8881268c4000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007f8cae82bf98 CR3: 000000005b1bc000 CR4: 00000000003526f0 >> Call Trace: >> >> arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 >> stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 >> kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 >> kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 >> slab_free_hook mm/slub.c:2378 [inline] >> slab_free mm/slub.c:4680 [inline] >> kmem_cache_free+0x3ef/0x510 mm/slub.c:4782 >> f2fs_read_end_io+0x398/0x9d0 fs/f2fs/data.c:-1 >> f2fs_submit_page_read+0x116/0x190 fs/f2fs/data.c:1110 >> f2fs_get_read_data_folio+0x4a4/0x7d0 fs/f2fs/data.c:1268 >> gc_data_segment fs/f2fs/gc.c:1641 [inline] >> do_garbage_collect+0x3898/0x6410 fs/f2fs/gc.c:1826 >> f2fs_gc+0xca9/0x2580 fs/f2fs/gc.c:1931 >> f2fs_balance_fs+0x5fb/0x7f0 fs/f2fs/segment.c:466 >> f2fs_map_blocks+0x345f/0x4130 fs/f2fs/data.c:1792 >> f2fs_expand_inode_data+0x5b1/0xa60 fs/f2fs/file.c:1923 >> f2fs_fallocate+0x4f8/0x990 fs/f2fs/file.c:2026 > > This report complains that it took more than 100s for f2fs_fallocate() to > complete after locking inode [1], right? I guess so, seems f2fs_gc() was blocked or in a deadloop somehow. Thanks, > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/f2fs/file.c#n1991 > >> vfs_fallocate+0x672/0x7f0 fs/open.c:342 >> ioctl_preallocate fs/ioctl.c:290 [inline] >> file_ioctl+0x61d/0x780 fs/ioctl.c:-1 >> do_vfs_ioctl+0xb36/0x1440 fs/ioctl.c:577 >> __do_sys_ioctl fs/ioctl.c:596 [inline] >> __se_sys_ioctl+0x82/0x170 fs/ioctl.c:584 >> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] >> do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 >> entry_SYSCALL_64_after_hwframe+0x77/0x7f _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 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List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, syzbot , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [f2fs?] INFO: task hung in f2fs_llseek To: Hillf Danton References: <20250822222346.5267-1-hdanton@sina.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20250822222346.5267-1-hdanton@sina.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/23/2025 6:23 AM, Hillf Danton wrote: >> Date: Fri, 22 Aug 2025 11:56:27 -0700 >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: 3957a5720157 Merge tag 'cgroup-for-6.17-rc2-fixes' of git:.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=13e20c42580000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=e1e1566c7726877e >> dashboard link: https://syzkaller.appspot.com/bug?extid=942fb6ce3ac2843a1420 >> compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17db07bc580000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f62a34580000 >> >> Downloadable assets: >> disk image: https://storage.googleapis.com/syzbot-assets/c5cbe8650b9a/disk-3957a572.raw.xz >> vmlinux: https://storage.googleapis.com/syzbot-assets/51911bea9855/vmlinux-3957a572.xz >> kernel image: https://storage.googleapis.com/syzbot-assets/b07279b5fcc2/bzImage-3957a572.xz >> mounted in repro: https://storage.googleapis.com/syzbot-assets/f35e0e9a079a/mount_0.gz >> fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=10a5dfa2580000) >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+942fb6ce3ac2843a1420@syzkaller.appspotmail.com >> >> INFO: task syz.1.23:6086 blocked for more than 143 seconds. >> Tainted: G W syzkaller #0 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> task:syz.1.23 state:D stack:29352 pid:6086 tgid:6081 ppid:6062 task_flags:0x400040 flags:0x00004004 >> Call Trace: >> >> context_switch kernel/sched/core.c:5357 [inline] >> __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 >> __schedule_loop kernel/sched/core.c:7043 [inline] >> rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 >> rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] >> __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] >> __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 >> __rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114 >> rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] >> __down_read kernel/locking/rwsem.c:1466 [inline] >> down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539 >> inode_lock_shared include/linux/fs.h:884 [inline] >> f2fs_seek_block fs/f2fs/file.c:458 [inline] >> f2fs_llseek+0x1e5/0x1840 fs/f2fs/file.c:545 >> vfs_llseek fs/read_write.c:389 [inline] >> ksys_lseek fs/read_write.c:402 [inline] >> __do_sys_lseek fs/read_write.c:412 [inline] >> __se_sys_lseek fs/read_write.c:410 [inline] >> __x64_sys_lseek+0x155/0x1f0 fs/read_write.c:410 >> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] >> do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 >> entry_SYSCALL_64_after_hwframe+0x77/0x7f >> RIP: 0033:0x7f7c9077ebe9 >> RSP: 002b:00007f7c8fdcd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000008 >> RAX: ffffffffffffffda RBX: 00007f7c909a6090 RCX: 00007f7c9077ebe9 >> RDX: 0000000000000004 RSI: 0000000000000008 RDI: 0000000000000004 >> RBP: 00007f7c90801e19 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 >> R13: 00007f7c909a6128 R14: 00007f7c909a6090 R15: 00007fffeb5fe138 >> >> INFO: lockdep is turned off. >> NMI backtrace for cpu 1 >> CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Tainted: G W syzkaller #0 PREEMPT_{RT,(full)} >> Tainted: [W]=WARN >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 >> 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:328 [inline] >> watchdog+0xf93/0xfe0 kernel/hung_task.c:491 >> kthread+0x70e/0x8a0 kernel/kthread.c:463 >> ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 >> 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: 6274 Comm: syz.3.43 Tainted: G W syzkaller #0 PREEMPT_{RT,(full)} >> Tainted: [W]=WARN >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 >> RIP: 0010:unwind_next_frame+0x175d/0x2390 arch/x86/kernel/unwind_orc.c:648 >> Code: 28 84 c0 0f 85 19 0b 00 00 48 89 d0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 2b 0b 00 00 48 0f bf 03 49 01 c4 49 8d 56 40 4c 89 f7 <4c> 89 e6 eb 5d 49 8d 5e 40 48 89 d8 48 c1 e8 03 80 3c 28 00 74 08 >> RSP: 0018:ffffc90003b06438 EFLAGS: 00000283 >> RAX: fffffffffffffff0 RBX: ffffffff8fd32106 RCX: 0000000000000000 >> RDX: ffffc90003b06548 RSI: 0000000000000001 RDI: ffffc90003b06508 >> RBP: dffffc0000000000 R08: ffffc90003b06567 R09: 0000000000000000 >> R10: ffffc90003b06558 R11: fffff52000760cad R12: ffffc90003b069d0 >> R13: ffffc90003b06558 R14: ffffc90003b06508 R15: 1ffffffff1fa6421 >> FS: 00007f0008c3c6c0(0000) GS:ffff8881268c4000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007f8cae82bf98 CR3: 000000005b1bc000 CR4: 00000000003526f0 >> Call Trace: >> >> arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 >> stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 >> kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 >> kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 >> slab_free_hook mm/slub.c:2378 [inline] >> slab_free mm/slub.c:4680 [inline] >> kmem_cache_free+0x3ef/0x510 mm/slub.c:4782 >> f2fs_read_end_io+0x398/0x9d0 fs/f2fs/data.c:-1 >> f2fs_submit_page_read+0x116/0x190 fs/f2fs/data.c:1110 >> f2fs_get_read_data_folio+0x4a4/0x7d0 fs/f2fs/data.c:1268 >> gc_data_segment fs/f2fs/gc.c:1641 [inline] >> do_garbage_collect+0x3898/0x6410 fs/f2fs/gc.c:1826 >> f2fs_gc+0xca9/0x2580 fs/f2fs/gc.c:1931 >> f2fs_balance_fs+0x5fb/0x7f0 fs/f2fs/segment.c:466 >> f2fs_map_blocks+0x345f/0x4130 fs/f2fs/data.c:1792 >> f2fs_expand_inode_data+0x5b1/0xa60 fs/f2fs/file.c:1923 >> f2fs_fallocate+0x4f8/0x990 fs/f2fs/file.c:2026 > > This report complains that it took more than 100s for f2fs_fallocate() to > complete after locking inode [1], right? I guess so, seems f2fs_gc() was blocked or in a deadloop somehow. Thanks, > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/f2fs/file.c#n1991 > >> vfs_fallocate+0x672/0x7f0 fs/open.c:342 >> ioctl_preallocate fs/ioctl.c:290 [inline] >> file_ioctl+0x61d/0x780 fs/ioctl.c:-1 >> do_vfs_ioctl+0xb36/0x1440 fs/ioctl.c:577 >> __do_sys_ioctl fs/ioctl.c:596 [inline] >> __se_sys_ioctl+0x82/0x170 fs/ioctl.c:584 >> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] >> do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 >> entry_SYSCALL_64_after_hwframe+0x77/0x7f