EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock ================================================================== BUG: KCSAN: data-race in ktime_get_real_seconds / timekeeping_update_from_shadow write to 0xffffffff88edc0c8 of 280 bytes by interrupt on cpu 1: timekeeping_update_from_shadow+0x2b4/0x2f0 kernel/time/timekeeping.c:753 __timekeeping_advance+0xa3d/0xbc0 kernel/time/timekeeping.c:2377 timekeeping_advance kernel/time/timekeeping.c:2385 [inline] update_wall_time+0x24/0x90 kernel/time/timekeeping.c:2395 tick_do_update_jiffies64+0x169/0x1c0 kernel/time/tick-sched.c:149 tick_sched_do_timer kernel/time/tick-sched.c:253 [inline] tick_nohz_handler+0x8d/0x3d0 kernel/time/tick-sched.c:312 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x20f/0x5a0 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x21a/0x460 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 kcsan_setup_watchpoint+0x406/0x420 kernel/kcsan/core.c:705 strcmp+0x16/0x50 lib/string.c:283 kernfs_name_compare fs/kernfs/dir.c:343 [inline] kernfs_find_ns+0x11c/0x1c0 fs/kernfs/dir.c:877 kernfs_remove_by_name_ns+0x6a/0xf0 fs/kernfs/dir.c:1717 kernfs_remove_by_name include/linux/kernfs.h:633 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xa5/0x170 fs/sysfs/group.c:328 sysfs_remove_groups+0x3a/0x80 fs/sysfs/group.c:352 __kobject_del+0x4b/0x190 lib/kobject.c:595 kobject_del+0x2e/0x50 lib/kobject.c:627 ext4_unregister_sysfs+0x75/0x80 fs/ext4/sysfs.c:611 ext4_put_super+0x4c/0x7d0 fs/ext4/super.c:1292 generic_shutdown_super+0xe6/0x210 fs/super.c:643 kill_block_super+0x2a/0x70 fs/super.c:1722 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7444 deactivate_locked_super+0x75/0x1c0 fs/super.c:474 deactivate_super+0x97/0xa0 fs/super.c:507 cleanup_mnt+0x2a9/0x320 fs/namespace.c:1318 __cleanup_mnt+0x19/0x20 fs/namespace.c:1325 task_work_run+0x131/0x1a0 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0x1fe/0x740 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x1e1/0x2b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff88edc100 of 8 bytes by task 9733 on cpu 0: ktime_get_real_seconds+0x15/0x30 kernel/time/timekeeping.c:1013 save_error_info fs/ext4/super.c:657 [inline] ext4_handle_error+0x2ce/0x550 fs/ext4/super.c:704 __ext4_std_error+0x1a5/0x370 fs/ext4/super.c:970 ext4_reserve_inode_write+0x202/0x250 fs/ext4/inode.c:6298 __ext4_mark_inode_dirty+0x8c/0x3f0 fs/ext4/inode.c:6465 __ext4_ext_dirty+0xdb/0x1f0 fs/ext4/extents.c:206 ext4_split_extent_at+0x48c/0x990 fs/ext4/extents.c:3230 ext4_split_extent+0x1af/0x3b0 fs/ext4/extents.c:3406 ext4_split_convert_extents fs/ext4/extents.c:3743 [inline] ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3915 [inline] ext4_ext_map_blocks+0xb58/0x38a0 fs/ext4/extents.c:4274 ext4_map_create_blocks fs/ext4/inode.c:613 [inline] ext4_map_blocks+0x626/0xd20 fs/ext4/inode.c:816 mpage_map_one_extent fs/ext4/inode.c:2380 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline] ext4_do_writepages+0x15ef/0x27e0 fs/ext4/inode.c:2932 ext4_writepages+0x179/0x300 fs/ext4/inode.c:3026 do_writepages+0x1c6/0x310 mm/page-writeback.c:2598 __writeback_single_inode+0x80/0x7c0 fs/fs-writeback.c:1737 writeback_sb_inodes+0x4b0/0xb20 fs/fs-writeback.c:2030 wb_writeback+0x252/0x5c0 fs/fs-writeback.c:2216 wb_do_writeback fs/fs-writeback.c:2363 [inline] wb_workfn+0x194/0x910 fs/fs-writeback.c:2403 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340 worker_thread+0x582/0x770 kernel/workqueue.c:3421 kthread+0x489/0x510 kernel/kthread.c:463 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 value changed: 0x0000000069490751 -> 0x0000000069490752 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 9733 Comm: kworker/u8:23 Tainted: G W syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: writeback wb_workfn (flush-7:7) ================================================================== Buffer I/O error on dev loop7, logical block 1, lost sync page write Buffer I/O error on dev loop7, logical block 1, lost sync page write Buffer I/O error on dev loop7, logical block 1, lost sync page write Buffer I/O error on dev loop7, logical block 1, lost sync page write Buffer I/O error on dev loop7, logical block 1, lost sync page write EXT4-fs error: 77246 callbacks suppressed EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs: 86574 callbacks suppressed EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock kworker/u8:23: attempt to access beyond end of device loop7: rw=8534017, sector=2, nr_sectors = 2 limit=2 kworker/u8:23: attempt to access beyond end of device loop7: rw=8534017, sector=2, nr_sectors = 2 limit=2 kworker/u8:23: attempt to access beyond end of device loop7: rw=8534017, sector=2, nr_sectors = 2 limit=2 kworker/u8:23: attempt to access beyond end of device loop7: rw=8534017, sector=2, nr_sectors = 2 limit=2 kworker/u8:23: attempt to access beyond end of device loop7: rw=8534017, sector=2, nr_sectors = 2 limit=2 Buffer I/O error on dev loop7, logical block 1, lost sync page write Buffer I/O error on dev loop7, logical block 1, lost sync page write Buffer I/O error on dev loop7, logical block 1, lost sync page write Buffer I/O error on dev loop7, logical block 1, lost sync page write Buffer I/O error on dev loop7, logical block 1, lost sync page write EXT4-fs error: 107206 callbacks suppressed EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs error (device loop7) in ext4_reserve_inode_write:6298: Out of memory EXT4-fs error (device loop7): __ext4_ext_dirty:206: inode #18: comm kworker/u8:23: mark_inode_dirty error EXT4-fs: 107080 callbacks suppressed EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock EXT4-fs (loop7): I/O error while writing superblock