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BUG: KCSAN: data-race in __filemap_remove_folio / folio_mapping

write to 0xffffea00042cdd98 of 8 bytes by task 19613 on cpu 1:
 page_cache_delete mm/filemap.c:144 [inline]
 __filemap_remove_folio+0x1a5/0x2a0 mm/filemap.c:224
 filemap_remove_folio+0x6d/0x1d0 mm/filemap.c:253
 read_pages+0x1c3/0x480 mm/readahead.c:164
 page_cache_ra_unbounded+0x347/0x380 mm/readahead.c:297
 page_cache_sync_ra+0x689/0x6a0 mm/readahead.c:-1
 filemap_get_pages+0x2d0/0x1160 mm/filemap.c:2591
 filemap_read+0x237/0x990 mm/filemap.c:2702
 generic_file_read_iter+0x79/0x330 mm/filemap.c:2894
 ext4_file_read_iter+0x1cc/0x290 fs/ext4/file.c:-1
 copy_splice_read+0x3c1/0x5f0 fs/splice.c:363
 do_splice_read fs/splice.c:978 [inline]
 splice_direct_to_actor+0x290/0x680 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1227
 do_sendfile+0x380/0x640 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64 fs/read_write.c:1415 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1415
 x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffea00042cdd98 of 8 bytes by task 19622 on cpu 0:
 folio_mapping+0xa1/0x120 mm/util.c:701
 folio_evictable mm/internal.h:480 [inline]
 lru_add+0x80/0x430 mm/swap.c:136
 folio_batch_move_lru+0x174/0x230 mm/swap.c:168
 lru_add_drain_cpu+0x77/0x250 mm/swap.c:642
 lru_add_drain mm/swap.c:730 [inline]
 __folio_batch_release+0x44/0xb0 mm/swap.c:1049
 folio_batch_release include/linux/pagevec.h:101 [inline]
 __filemap_fdatawait_range mm/filemap.c:541 [inline]
 file_write_and_wait_range+0x241/0x2c0 mm/filemap.c:798
 generic_buffers_fsync_noflush+0x45/0x120 fs/buffer.c:611
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1ab/0x690 fs/ext4/fsync.c:147
 vfs_fsync_range+0x10a/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:2976 [inline]
 ext4_buffered_write_iter+0x34f/0x3c0 fs/ext4/file.c:305
 ext4_dio_write_iter fs/ext4/file.c:608 [inline]
 ext4_file_write_iter+0xdbf/0xf00 fs/ext4/file.c:716
 iter_file_splice_write+0x5ef/0x970 fs/splice.c:738
 do_splice_from fs/splice.c:935 [inline]
 direct_splice_actor+0x153/0x2a0 fs/splice.c:1158
 splice_direct_to_actor+0x30f/0x680 fs/splice.c:1102
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1227
 do_sendfile+0x380/0x640 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64 fs/read_write.c:1415 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1415
 x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888128ec8fe8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 19622 Comm: syz.5.4573 Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
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