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BUG: KCSAN: data-race in filemap_fault / generic_write_end

write to 0xffff88810a94f708 of 8 bytes by task 7449 on cpu 0:
 i_size_write include/linux/fs.h:886 [inline]
 generic_write_end+0xb1/0x350 fs/buffer.c:2168
 ext4_da_write_end+0x26c/0x620 fs/ext4/inode.c:3175
 generic_perform_write+0x264/0x3f0 mm/filemap.c:3783
 ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:285
 ext4_file_write_iter+0x2bb/0x11b0
 do_iter_write+0x494/0x750 fs/read_write.c:861
 vfs_iter_write+0x4c/0x70 fs/read_write.c:902
 iter_file_splice_write+0x44a/0x7c0 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:931
 splice_direct_to_actor+0x305/0x620 fs/splice.c:886
 do_splice_direct+0xfb/0x180 fs/splice.c:974
 do_sendfile+0x3bf/0x910 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1309
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810a94f708 of 8 bytes by task 7451 on cpu 1:
 i_size_read include/linux/fs.h:864 [inline]
 filemap_fault+0x51e/0x6a0 mm/filemap.c:3221
 __do_fault mm/memory.c:4163 [inline]
 do_cow_fault+0x214/0x5f0 mm/memory.c:4544
 do_fault+0x345/0xaf0 mm/memory.c:4645
 handle_pte_fault mm/memory.c:4931 [inline]
 __handle_mm_fault mm/memory.c:5073 [inline]
 handle_mm_fault+0x8c5/0xb20 mm/memory.c:5219
 do_user_addr_fault+0x4a1/0x980 arch/x86/mm/fault.c:1428
 handle_page_fault arch/x86/mm/fault.c:1519 [inline]
 exc_page_fault+0x60/0x160 arch/x86/mm/fault.c:1575
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570
 copy_user_enhanced_fast_string+0xa/0x40 arch/x86/lib/copy_user_64.S:165
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 copyout+0x72/0x90 lib/iov_iter.c:170
 _copy_to_iter+0x288/0x910 lib/iov_iter.c:529
 copy_page_to_iter+0x31b/0x450 lib/iov_iter.c:727
 copy_folio_to_iter include/linux/uio.h:172 [inline]
 filemap_read+0x11db/0x1510 mm/filemap.c:2745
 generic_file_read_iter+0x72/0x320 mm/filemap.c:2840
 ext4_file_read_iter+0x1c8/0x280
 do_iter_read+0x492/0x760 fs/read_write.c:796
 vfs_readv fs/read_write.c:916 [inline]
 do_preadv+0x159/0x230 fs/read_write.c:1008
 __do_sys_preadv fs/read_write.c:1058 [inline]
 __se_sys_preadv fs/read_write.c:1053 [inline]
 __x64_sys_preadv+0x54/0x60 fs/read_write.c:1053
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000560000 -> 0x0000000000560018

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7451 Comm: syz-executor.4 Not tainted 6.2.0-rc4-syzkaller-00077-gd368967cb103-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
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