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BUG: KCSAN: data-race in do_sync_mmap_readahead / do_sync_mmap_readahead

write to 0xffff888104b567a0 of 4 bytes by task 26576 on cpu 0:
 do_sync_mmap_readahead+0x329/0x3a0 mm/filemap.c:3187
 filemap_fault+0x3c1/0xb20 mm/filemap.c:3282
 __do_fault mm/memory.c:4141 [inline]
 do_read_fault mm/memory.c:4492 [inline]
 do_fault mm/memory.c:4621 [inline]
 handle_pte_fault mm/memory.c:4909 [inline]
 __handle_mm_fault mm/memory.c:5051 [inline]
 handle_mm_fault+0x115d/0x21d0 mm/memory.c:5197
 do_user_addr_fault arch/x86/mm/fault.c:1407 [inline]
 handle_page_fault arch/x86/mm/fault.c:1498 [inline]
 exc_page_fault+0x45f/0x640 arch/x86/mm/fault.c:1554
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
 fault_in_readable+0xa4/0x1b0 mm/gup.c:1855
 fault_in_iov_iter_readable+0x7f/0x180 lib/iov_iter.c:350
 generic_perform_write+0x106/0x3d0 mm/filemap.c:3916
 ext4_buffered_write_iter+0x234/0x3e0 fs/ext4/file.c:289
 ext4_file_write_iter+0xd7/0x10e0
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x45a/0x750 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 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 0xffff888104b567a0 of 4 bytes by task 26577 on cpu 1:
 do_sync_mmap_readahead+0x329/0x3a0 mm/filemap.c:3187
 filemap_fault+0x3c1/0xb20 mm/filemap.c:3282
 __do_fault mm/memory.c:4141 [inline]
 do_read_fault mm/memory.c:4492 [inline]
 do_fault mm/memory.c:4621 [inline]
 handle_pte_fault mm/memory.c:4909 [inline]
 __handle_mm_fault mm/memory.c:5051 [inline]
 handle_mm_fault+0x115d/0x21d0 mm/memory.c:5197
 do_user_addr_fault arch/x86/mm/fault.c:1407 [inline]
 handle_page_fault arch/x86/mm/fault.c:1498 [inline]
 exc_page_fault+0x45f/0x640 arch/x86/mm/fault.c:1554
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
 copy_user_short_string+0xa/0x40 arch/x86/lib/copy_user_64.S:231
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline]
 copyin lib/iov_iter.c:183 [inline]
 _copy_from_iter+0x130/0x8c0 lib/iov_iter.c:628
 copy_from_iter include/linux/uio.h:189 [inline]
 do_tty_write drivers/tty/tty_io.c:1015 [inline]
 file_tty_write+0x368/0x600 drivers/tty/tty_io.c:1089
 tty_write+0x28/0x30 drivers/tty/tty_io.c:1110
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x45a/0x750 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 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: 0x00000000 -> 0x00000020

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 26577 Comm: syz-executor.1 Not tainted 6.2.0-syzkaller-13467-g0988a0ea7919-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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