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BUG: KCSAN: data-race in next_uptodate_page / shmem_write_end

write to 0xffff8881350440d8 of 8 bytes by task 14498 on cpu 0:
 i_size_write include/linux/fs.h:901 [inline]
 shmem_write_end+0x9a/0x4a0 mm/shmem.c:2598
 generic_perform_write+0x253/0x3d0 mm/filemap.c:3957
 __generic_file_write_iter+0xe6/0x290 mm/filemap.c:4074
 generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4106
 call_write_iter include/linux/fs.h:1872 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4ab/0x7d0 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

read to 0xffff8881350440d8 of 8 bytes by task 14506 on cpu 1:
 i_size_read include/linux/fs.h:879 [inline]
 next_uptodate_page+0x47b/0x560 mm/filemap.c:3477
 next_map_page mm/filemap.c:3502 [inline]
 filemap_map_pages+0x73c/0x860 mm/filemap.c:3574
 do_fault_around mm/memory.c:4493 [inline]
 do_read_fault mm/memory.c:4525 [inline]
 do_fault mm/memory.c:4659 [inline]
 do_pte_missing mm/memory.c:3647 [inline]
 handle_pte_fault mm/memory.c:4947 [inline]
 __handle_mm_fault mm/memory.c:5089 [inline]
 handle_mm_fault+0x1120/0x2c60 mm/memory.c:5243
 faultin_page mm/gup.c:969 [inline]
 __get_user_pages+0x363/0xc30 mm/gup.c:1191
 populate_vma_page_range mm/gup.c:1587 [inline]
 __mm_populate+0x23d/0x370 mm/gup.c:1696
 mm_populate include/linux/mm.h:3176 [inline]
 vm_mmap_pgoff+0x1a3/0x240 mm/util.c:548
 ksys_mmap_pgoff+0x2b8/0x330 mm/mmap.c:1440
 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: 0x0000000000eac000 -> 0x0000000000eaf000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14506 Comm: syz-executor.2 Not tainted 6.4.0-syzkaller-01761-g6aeadf7896bf #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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