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BUG: KCSAN: data-race in delete_from_page_cache_batch / file_write_and_wait_range

read-write to 0xffff88811a91d478 of 8 bytes by task 6727 on cpu 0:
 page_cache_delete_batch mm/filemap.c:317 [inline]
 delete_from_page_cache_batch+0x553/0x740 mm/filemap.c:336
 truncate_inode_pages_range+0x1fe/0x7e0 mm/truncate.c:405
 truncate_inode_pages+0x24/0x30 mm/truncate.c:485
 ext4_truncate_failed_write fs/ext4/truncate.h:21 [inline]
 ext4_write_end+0x540/0x730 fs/ext4/inode.c:1491
 generic_perform_write+0x311/0x490 mm/filemap.c:4335
 ext4_buffered_write_iter+0x1ee/0x3c0 fs/ext4/file.c:300
 ext4_file_write_iter+0x380/0xf70 fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x5a6/0x9f0 fs/read_write.c:688
 ksys_write+0xdc/0x1a0 fs/read_write.c:740
 __do_sys_write fs/read_write.c:751 [inline]
 __se_sys_write fs/read_write.c:748 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:748
 x64_sys_call+0x27e1/0x3020 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811a91d478 of 8 bytes by task 6745 on cpu 1:
 mapping_needs_writeback mm/filemap.c:634 [inline]
 file_write_and_wait_range+0x65/0x2f0 mm/filemap.c:785
 generic_buffers_fsync_noflush+0x45/0x130 fs/buffer.c:610
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1aa/0x680 fs/ext4/fsync.c:147
 vfs_fsync_range fs/sync.c:188 [inline]
 vfs_fsync fs/sync.c:202 [inline]
 do_fsync fs/sync.c:213 [inline]
 __do_sys_fdatasync fs/sync.c:223 [inline]
 __se_sys_fdatasync fs/sync.c:221 [inline]
 __x64_sys_fdatasync+0x83/0xe0 fs/sync.c:221
 x64_sys_call+0x2d1f/0x3020 arch/x86/include/generated/asm/syscalls_64.h:76
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000016 -> 0x0000000000000015

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6745 Comm: syz.8.751 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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