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BUG: KCSAN: data-race in __filemap_remove_folio / folio_mapping

write to 0xffffea000417ef98 of 8 bytes by task 15153 on cpu 0:
 page_cache_delete mm/filemap.c:145 [inline]
 __filemap_remove_folio+0x201/0x2e0 mm/filemap.c:228
 filemap_remove_folio+0x6d/0x1d0 mm/filemap.c:258
 truncate_inode_folio+0x42/0x50 mm/truncate.c:176
 shmem_undo_range+0x26d/0xb10 mm/shmem.c:1145
 shmem_fallocate+0x881/0x920 mm/shmem.c:3772
 vfs_fallocate+0x3b6/0x400 fs/open.c:338
 ksys_fallocate fs/open.c:362 [inline]
 __do_sys_fallocate fs/open.c:367 [inline]
 __se_sys_fallocate fs/open.c:365 [inline]
 __x64_sys_fallocate+0x7a/0xd0 fs/open.c:365
 x64_sys_call+0x298e/0x3020 arch/x86/include/generated/asm/syscalls_64.h:286
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffea000417ef98 of 8 bytes by task 15164 on cpu 1:
 folio_mapping+0xa1/0xe0 mm/util.c:732
 folio_evictable mm/internal.h:584 [inline]
 sort_folio mm/vmscan.c:4593 [inline]
 scan_folios mm/vmscan.c:4720 [inline]
 isolate_folios mm/vmscan.c:4812 [inline]
 evict_folios+0xdb0/0x3370 mm/vmscan.c:4842
 try_to_shrink_lruvec+0x858/0xc20 mm/vmscan.c:5009
 lru_gen_shrink_lruvec mm/vmscan.c:5173 [inline]
 shrink_lruvec+0x256/0x1bc0 mm/vmscan.c:5932
 shrink_node_memcgs mm/vmscan.c:6171 [inline]
 shrink_node+0x697/0x20a0 mm/vmscan.c:6215
 shrink_zones mm/vmscan.c:6454 [inline]
 do_try_to_free_pages+0x408/0xc90 mm/vmscan.c:6516
 try_to_free_mem_cgroup_pages+0x201/0x420 mm/vmscan.c:6838
 try_charge_memcg+0x373/0xa10 mm/memcontrol.c:2618
 charge_memcg+0x6d/0x120 mm/memcontrol.c:5006
 __mem_cgroup_charge+0x28/0xb0 mm/memcontrol.c:5023
 mem_cgroup_charge include/linux/memcontrol.h:644 [inline]
 shmem_alloc_and_add_folio mm/shmem.c:1985 [inline]
 shmem_get_folio_gfp+0x47b/0xd60 mm/shmem.c:2564
 shmem_fault+0xf6/0x250 mm/shmem.c:2765
 __do_fault mm/memory.c:5458 [inline]
 do_read_fault mm/memory.c:5893 [inline]
 do_fault mm/memory.c:6027 [inline]
 do_pte_missing mm/memory.c:4550 [inline]
 handle_pte_fault mm/memory.c:6411 [inline]
 __handle_mm_fault mm/memory.c:6549 [inline]
 handle_mm_fault+0x16cb/0x2e70 mm/memory.c:6718
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x1290/0x1f10 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:4137 [inline]
 vm_mmap_pgoff+0x23b/0x2d0 mm/util.c:586
 ksys_mmap_pgoff+0xc1/0x310 mm/mmap.c:606
 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/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88811b5d37a0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15164 Comm: syz.0.17322 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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