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BUG: KCSAN: data-race in file_update_time / generic_update_time

read to 0xffff888129cad798 of 8 bytes by task 3200 on cpu 0:
 file_update_time+0xbb/0x2d0 fs/inode.c:1893
 filemap_page_mkwrite+0xb3/0x1d0 mm/filemap.c:2656
 do_page_mkwrite+0xfa/0x210 mm/memory.c:2364
 do_shared_fault mm/memory.c:3738 [inline]
 do_fault mm/memory.c:3806 [inline]
 handle_pte_fault mm/memory.c:4033 [inline]
 __handle_mm_fault+0x1d99/0x2cf0 mm/memory.c:4163
 handle_mm_fault+0x21c/0x540 mm/memory.c:4200
 do_user_addr_fault arch/x86/mm/fault.c:1442 [inline]
 do_page_fault+0x4a4/0xa52 arch/x86/mm/fault.c:1517
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203
 copy_user_enhanced_fast_string+0xe/0x30 arch/x86/lib/copy_user_64.S:204
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:128 [inline]
 copyout+0xa8/0xb0 lib/iov_iter.c:143
 copy_page_to_iter_iovec lib/iov_iter.c:212 [inline]
 copy_page_to_iter+0x25c/0x910 lib/iov_iter.c:921
 generic_file_buffered_read mm/filemap.c:2122 [inline]
 generic_file_read_iter+0x96a/0x1490 mm/filemap.c:2302
 blkdev_read_iter+0xae/0xe0 fs/block_dev.c:2039
 call_read_iter include/linux/fs.h:1895 [inline]
 do_iter_readv_writev+0x570/0x5d0 fs/read_write.c:691
 do_iter_read+0x1e4/0x3a0 fs/read_write.c:933
 vfs_readv+0x9c/0xf0 fs/read_write.c:1053
 do_preadv+0x129/0x1c0 fs/read_write.c:1145
 __do_sys_preadv fs/read_write.c:1195 [inline]
 __se_sys_preadv fs/read_write.c:1190 [inline]
 __x64_sys_preadv+0x5e/0x80 fs/read_write.c:1190
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888129cad798 of 16 bytes by task 3116 on cpu 1:
 generic_update_time+0x109/0x270 fs/inode.c:1674
 update_time+0x7d/0x90 fs/inode.c:1694
 file_update_time+0x205/0x2d0 fs/inode.c:1909
 filemap_page_mkwrite+0xb3/0x1d0 mm/filemap.c:2656
 do_page_mkwrite+0xfa/0x210 mm/memory.c:2364
 do_shared_fault mm/memory.c:3738 [inline]
 do_fault mm/memory.c:3806 [inline]
 handle_pte_fault mm/memory.c:4033 [inline]
 __handle_mm_fault+0x1d99/0x2cf0 mm/memory.c:4163
 handle_mm_fault+0x21c/0x540 mm/memory.c:4200
 do_user_addr_fault arch/x86/mm/fault.c:1442 [inline]
 do_page_fault+0x4a4/0xa52 arch/x86/mm/fault.c:1517
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203
 copy_user_enhanced_fast_string+0xe/0x30 arch/x86/lib/copy_user_64.S:204
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:128 [inline]
 copyout+0xa8/0xb0 lib/iov_iter.c:143
 copy_page_to_iter_iovec lib/iov_iter.c:212 [inline]
 copy_page_to_iter+0x25c/0x910 lib/iov_iter.c:921
 generic_file_buffered_read mm/filemap.c:2122 [inline]
 generic_file_read_iter+0x96a/0x1490 mm/filemap.c:2302
 blkdev_read_iter+0xae/0xe0 fs/block_dev.c:2039
 call_read_iter include/linux/fs.h:1895 [inline]
 do_iter_readv_writev+0x570/0x5d0 fs/read_write.c:691
 do_iter_read+0x1e4/0x3a0 fs/read_write.c:933
 vfs_readv+0x9c/0xf0 fs/read_write.c:1053
 do_preadv+0x129/0x1c0 fs/read_write.c:1145
 __do_sys_preadv fs/read_write.c:1195 [inline]
 __se_sys_preadv fs/read_write.c:1190 [inline]
 __x64_sys_preadv+0x5e/0x80 fs/read_write.c:1190
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3116 Comm: syz-executor.5 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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