EXT4-fs error (device loop4): ext4_find_dest_de:2052: inode #2: block 13: comm syz.4.131: bad entry in directory: directory entry overrun - offset=108, inode=4294901777, rec_len=1024, size=1024 fake=0
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BUG: KCSAN: data-race in ktime_get / timekeeping_update_from_shadow

write to 0xffffffff895f2508 of 320 bytes by interrupt on cpu 0:
 timekeeping_update_from_shadow+0x448/0x480 kernel/time/timekeeping.c:866
 __timekeeping_advance+0xb36/0xcf0 kernel/time/timekeeping.c:2663
 timekeeping_advance kernel/time/timekeeping.c:2671 [inline]
 update_wall_time+0x21/0x50 kernel/time/timekeeping.c:2681
 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+0x88/0x380 kernel/time/tick-sched.c:310
 __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
 __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2124
 hrtimer_interrupt+0x27b/0x860 kernel/time/hrtimer.c:2243
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 kcsan_setup_watchpoint+0x42b/0x4a0 kernel/kcsan/core.c:713
 page_counter_try_charge+0x7d/0x310 mm/page_counter.c:143
 try_charge_memcg+0x2b8/0xae0 mm/memcontrol.c:2671
 charge_memcg+0x16f/0x220 mm/memcontrol.c:5210
 __mem_cgroup_charge+0x28/0xb0 mm/memcontrol.c:5227
 mem_cgroup_charge include/linux/memcontrol.h:662 [inline]
 shmem_alloc_and_add_folio mm/shmem.c:1985 [inline]
 shmem_get_folio_gfp+0x49f/0xd90 mm/shmem.c:2528
 shmem_fault+0xf6/0x250 mm/shmem.c:2729
 __do_fault mm/memory.c:5565 [inline]
 do_read_fault mm/memory.c:6000 [inline]
 do_fault mm/memory.c:6134 [inline]
 do_pte_missing mm/memory.c:4700 [inline]
 handle_pte_fault mm/memory.c:6558 [inline]
 __handle_mm_fault mm/memory.c:6707 [inline]
 handle_mm_fault+0x2310/0x3bb0 mm/memory.c:6876
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x12e9/0x1eb0 mm/gup.c:1428
 populate_vma_page_range mm/gup.c:1860 [inline]
 __mm_populate+0x242/0x390 mm/gup.c:1963
 mm_populate include/linux/mm.h:4288 [inline]
 vm_mmap_pgoff+0x23b/0x2d0 mm/util.c:586
 ksys_mmap_pgoff+0xc1/0x310 mm/mmap.c:619
 x64_sys_call+0x23b3/0x2550 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff895f2518 of 8 bytes by task 4134 on cpu 1:
 timekeeping_cycles_to_ns kernel/time/timekeeping.c:459 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:482 [inline]
 ktime_get+0xcf/0x240 kernel/time/timekeeping.c:1004
 ktime_get_ns include/linux/timekeeping.h:174 [inline]
 blk_time_get_ns block/blk.h:723 [inline]
 blk_account_io_start+0x18d/0x450 block/blk-mq.c:1100
 blk_mq_bio_to_request block/blk-mq.c:2676 [inline]
 blk_mq_submit_bio+0xba2/0x1120 block/blk-mq.c:3182
 __submit_bio+0x54/0x3d0 block/blk-core.c:673
 __submit_bio_noacct_mq block/blk-core.c:756 [inline]
 submit_bio_noacct_nocheck+0x153/0x620 block/blk-core.c:790
 submit_bio_noacct+0x760/0x980 block/blk-core.c:925
 submit_bio+0x2a4/0x2c0 block/blk-core.c:966
 blk_crypto_submit_bio include/linux/blk-crypto.h:212 [inline]
 __bh_submit+0x33f/0x380 fs/buffer.c:1132
 bh_submit+0x26/0x30 fs/buffer.c:1146
 ext4_commit_super+0x19c/0x260 fs/ext4/super.c:6357
 ext4_handle_error+0x46f/0x570 fs/ext4/super.c:725
 __ext4_error_inode+0x1af/0x3a0 fs/ext4/super.c:871
 __ext4_check_dir_entry+0x527/0x540 fs/ext4/dir.c:121
 ext4_find_dest_de+0x109/0x300 fs/ext4/namei.c:2051
 add_dirent_to_buf+0x14a/0x340 fs/ext4/namei.c:2123
 __ext4_add_entry+0x343/0x1f10 fs/ext4/namei.c:2425
 ext4_add_entry fs/ext4/namei.c:2469 [inline]
 ext4_mkdir+0x371/0x790 fs/ext4/namei.c:3029
 vfs_mkdir+0x291/0x3e0 fs/namei.c:5410
 filename_mkdirat+0x138/0x300 fs/namei.c:5443
 __do_sys_mkdirat fs/namei.c:5464 [inline]
 __se_sys_mkdirat+0x32/0xf0 fs/namei.c:5461
 __x64_sys_mkdirat+0x43/0x50 fs/namei.c:5461
 x64_sys_call+0x368/0x2550 arch/x86/include/generated/asm/syscalls_64.h:259
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000021fd20f447 -> 0x00000021fe70a5b4

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4134 Comm: syz.4.131 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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