==================================================================
BUG: KCSAN: data-race in drop_nlink / vfs_coredump

write to 0xffff88811b612690 of 4 bytes by task 4734 on cpu 1:
 drop_nlink+0x3d/0xa0 fs/inode.c:419
 __simple_unlink fs/libfs.c:794 [inline]
 simple_unlink+0x60/0x80 fs/libfs.c:808
 shmem_unlink+0x12d/0x140 mm/shmem.c:4005
 vfs_unlink+0x1c7/0x490 fs/namei.c:5470
 filename_unlinkat+0x1e2/0x410 fs/namei.c:5540
 coredump_file fs/coredump.c:903 [inline]
 do_coredump fs/coredump.c:1100 [inline]
 vfs_coredump+0x1556/0x3130 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 kernel/entry/common.c:98 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0xf7/0x520 kernel/entry/common.c:219
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffff88811b612690 of 4 bytes by task 4735 on cpu 0:
 coredump_file fs/coredump.c:938 [inline]
 do_coredump fs/coredump.c:1100 [inline]
 vfs_coredump+0x166a/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 kernel/entry/common.c:98 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0xf7/0x520 kernel/entry/common.c:219
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4735 Comm: syz.6.326 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================