EXT4-fs (loop9): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
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BUG: KCSAN: data-race in __filemap_remove_folio / folio_mapping

write to 0xffffea000476a558 of 8 bytes by task 10532 on cpu 0:
 page_cache_delete mm/filemap.c:145 [inline]
 __filemap_remove_folio+0x201/0x300 mm/filemap.c:228
 filemap_remove_folio+0x6d/0x1d0 mm/filemap.c:257
 read_pages+0x1c3/0x480 mm/readahead.c:167
 page_cache_ra_unbounded+0x34f/0x440 mm/readahead.c:302
 do_page_cache_ra mm/readahead.c:332 [inline]
 page_cache_ra_order+0x145/0x220 mm/readahead.c:535
 do_sync_mmap_readahead+0x33d/0x350 mm/filemap.c:3400
 filemap_fault+0x362/0xbb0 mm/filemap.c:3549
 __do_fault+0xbc/0x200 mm/memory.c:5323
 do_read_fault mm/memory.c:5758 [inline]
 do_fault mm/memory.c:5892 [inline]
 do_pte_missing mm/memory.c:4404 [inline]
 handle_pte_fault mm/memory.c:6276 [inline]
 __handle_mm_fault mm/memory.c:6414 [inline]
 handle_mm_fault+0x11d7/0x3030 mm/memory.c:6583
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x1023/0x1ea0 mm/gup.c:1428
 populate_vma_page_range mm/gup.c:1860 [inline]
 __mm_populate+0x242/0x390 mm/gup.c:1963
 mm_populate include/linux/mm.h:3683 [inline]
 vm_mmap_pgoff+0x23b/0x2d0 mm/util.c:586
 ksys_mmap_pgoff+0x267/0x310 mm/mmap.c:604
 x64_sys_call+0x14df/0x3020 arch/x86/include/generated/asm/syscalls_64.h:10
 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 0xffffea000476a558 of 8 bytes by task 10529 on cpu 1:
 folio_mapping+0xa1/0xe0 mm/util.c:703
 folio_evictable mm/internal.h:499 [inline]
 lru_add+0x8d/0x480 mm/swap.c:136
 folio_batch_move_lru+0x1c5/0x270 mm/swap.c:172
 __folio_batch_add_and_move mm/swap.c:196 [inline]
 folio_add_lru+0x149/0x1e0 mm/swap.c:511
 filemap_add_folio+0x267/0x350 mm/filemap.c:982
 page_cache_ra_unbounded+0x204/0x440 mm/readahead.c:280
 do_page_cache_ra mm/readahead.c:332 [inline]
 page_cache_ra_order+0x145/0x220 mm/readahead.c:535
 page_cache_sync_ra+0x52d/0x6a0 mm/readahead.c:626
 filemap_get_pages+0x30a/0x1260 mm/filemap.c:2690
 filemap_splice_read+0x3c6/0x780 mm/filemap.c:3079
 ext4_file_splice_read+0x8f/0xb0 fs/ext4/file.c:159
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26e/0x670 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1230
 do_sendfile+0x382/0x650 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1433 [inline]
 __se_sys_sendfile64 fs/read_write.c:1419 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1419
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 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: 0xffff88811a497b60 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 10529 Comm: syz.9.2403 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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EXT4-fs (loop9): Delayed block allocation failed for inode 15 at logical offset 0 with max blocks 2 with error 28