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BUG: KCSAN: data-race in fsnotify / fsnotify_detach_mark

write to 0xffff888105359684 of 4 bytes by task 454 on cpu 0:
 fsnotify_detach_mark+0xb9/0x160 fs/notify/mark.c:558
 fsnotify_clear_marks_by_group+0x301/0x4b0 fs/notify/mark.c:1031
 fsnotify_destroy_group+0x53/0x180 fs/notify/group.c:61
 inotify_release+0x1f/0x30 fs/notify/inotify/inotify_user.c:308
 __fput+0x29b/0x650 fs/file_table.c:469
 ____fput+0x1c/0x30 fs/file_table.c:497
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x4ae/0x1600 kernel/exit.c:976
 do_group_exit+0xfe/0x140 kernel/exit.c:1118
 get_signal+0xe54/0xf60 kernel/signal.c:3034
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x6a/0x6f0 kernel/entry/common.c:98
 __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 include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x249/0x370 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888105359684 of 4 bytes by task 441 on cpu 1:
 send_to_group fs/notify/fsnotify.c:349 [inline]
 fsnotify+0xd77/0x1730 fs/notify/fsnotify.c:592
 __fsnotify_parent+0x358/0x3a0 fs/notify/fsnotify.c:238
 fsnotify_parent include/linux/fsnotify.h:96 [inline]
 fsnotify_path include/linux/fsnotify.h:113 [inline]
 fsnotify_file include/linux/fsnotify.h:127 [inline]
 fsnotify_modify include/linux/fsnotify.h:433 [inline]
 __kernel_write_iter+0x4c9/0x590 fs/read_write.c:625
 dump_emit_page fs/coredump.c:1299 [inline]
 dump_user_range+0xa7d/0xdb0 fs/coredump.c:1373
 elf_core_dump+0x21a2/0x2330 fs/binfmt_elf.c:2110
 coredump_write+0xacc/0xdd0 fs/coredump.c:1050
 do_coredump fs/coredump.c:1127 [inline]
 vfs_coredump+0x26c7/0x3130 fs/coredump.c:1201
 get_signal+0xd80/0xf60 kernel/signal.c:3019
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x6a/0x6f0 kernel/entry/common.c:98
 __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 include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x249/0x370 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000013 -> 0x00000010

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 441 Comm: syz.7.13551 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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