syzbot

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BUG: KCSAN: data-race in fill_mg_cmtime / inode_update_timestamps

write to 0xffff8881180986c4 of 4 bytes by task 8925 on cpu 0:
 inode_set_mtime_to_ts include/linux/fs.h:1648 [inline]
 inode_update_timestamps+0x139/0x250 fs/inode.c:2070
 generic_update_time fs/inode.c:2105 [inline]
 inode_update_time fs/inode.c:2125 [inline]
 __file_update_time fs/inode.c:2353 [inline]
 file_update_time+0x219/0x2b0 fs/inode.c:2383
 shmem_file_write_iter+0x99/0xe0 mm/shmem.c:3290
 __kernel_write_iter+0x24b/0x4e0 fs/read_write.c:612
 dump_emit_page fs/coredump.c:884 [inline]
 dump_user_range+0x3ac/0x550 fs/coredump.c:945
 elf_core_dump+0x1bdc/0x1ce0 fs/binfmt_elf.c:2129
 do_coredump+0x1898/0x1f40 fs/coredump.c:758
 get_signal+0xd4f/0x1000 kernel/signal.c:3001
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 irqentry_exit_to_user_mode+0xa7/0x120 kernel/entry/common.c:231
 irqentry_exit+0x12/0x50 kernel/entry/common.c:334
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffff8881180986c4 of 4 bytes by task 3496 on cpu 1:
 inode_get_mtime_nsec include/linux/fs.h:1634 [inline]
 inode_get_mtime include/linux/fs.h:1640 [inline]
 fill_mg_cmtime+0x58/0x280 fs/stat.c:55
 generic_fillattr+0x241/0x330 fs/stat.c:99
 shmem_getattr+0x17b/0x200 mm/shmem.c:1177
 vfs_getattr_nosec fs/stat.c:208 [inline]
 vfs_getattr fs/stat.c:246 [inline]
 vfs_statx_path+0x171/0x2d0 fs/stat.c:283
 vfs_statx+0xe1/0x170 fs/stat.c:347
 vfs_fstatat fs/stat.c:366 [inline]
 __do_sys_newfstatat fs/stat.c:530 [inline]
 __se_sys_newfstatat+0xdc/0x300 fs/stat.c:524
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:524
 x64_sys_call+0x236d/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x391a99b2 -> 0x39b330c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3496 Comm: syz-executor Tainted: G        W          6.12.0-syzkaller-12113-gbcc8eda6d349 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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