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BUG: KCSAN: data-race in inode_needs_update_time / inode_update_timestamps

read to 0xffff888106744198 of 8 bytes by task 32697 on cpu 0:
 timespec64_equal include/linux/time64.h:49 [inline]
 inode_needs_update_time+0x1c0/0x2f0 fs/inode.c:2115
 file_update_time+0x2d/0x140 fs/inode.c:2161
 ext4_page_mkwrite+0x1a4/0xb70 fs/ext4/inode.c:6074
 do_page_mkwrite mm/memory.c:2931 [inline]
 do_shared_fault mm/memory.c:4647 [inline]
 do_fault mm/memory.c:4709 [inline]
 do_pte_missing mm/memory.c:3669 [inline]
 handle_pte_fault mm/memory.c:4978 [inline]
 __handle_mm_fault mm/memory.c:5119 [inline]
 handle_mm_fault+0x1874/0x2cc0 mm/memory.c:5284
 faultin_page mm/gup.c:956 [inline]
 __get_user_pages+0x402/0xe40 mm/gup.c:1239
 __get_user_pages_locked mm/gup.c:1504 [inline]
 __gup_longterm_locked+0x1147/0x13c0 mm/gup.c:2198
 pin_user_pages_remote+0x114/0x170 mm/gup.c:3346
 process_vm_rw_single_vec mm/process_vm_access.c:105 [inline]
 process_vm_rw_core mm/process_vm_access.c:215 [inline]
 process_vm_rw+0x4f4/0x8c0 mm/process_vm_access.c:283
 __do_sys_process_vm_writev mm/process_vm_access.c:303 [inline]
 __se_sys_process_vm_writev mm/process_vm_access.c:298 [inline]
 __x64_sys_process_vm_writev+0x7a/0x90 mm/process_vm_access.c:298
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

write to 0xffff888106744198 of 8 bytes by task 32689 on cpu 1:
 inode_update_timestamps+0x389/0x530 fs/inode.c:1896
 generic_update_time fs/inode.c:1929 [inline]
 inode_update_time fs/inode.c:1949 [inline]
 __file_update_time fs/inode.c:2135 [inline]
 file_modified_flags+0x144/0x1d0 fs/inode.c:2206
 file_modified+0x17/0x20 fs/inode.c:2222
 ext4_write_checks fs/ext4/file.c:279 [inline]
 ext4_buffered_write_iter+0x1d8/0x370 fs/ext4/file.c:295
 ext4_file_write_iter+0xd6/0x1200
 do_iter_write+0x4b4/0x7b0 fs/read_write.c:860
 vfs_iter_write+0x56/0x70 fs/read_write.c:901
 iter_file_splice_write+0x462/0x7e0 fs/splice.c:736
 do_splice_from fs/splice.c:933 [inline]
 direct_splice_actor+0x8a/0xb0 fs/splice.c:1142
 splice_direct_to_actor+0x31d/0x690 fs/splice.c:1088
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3b6/0x9a0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000038e95c2d -> 0x000000003981f2ad

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 32689 Comm: syz-executor.0 Not tainted 6.6.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
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