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BUG: KCSAN: data-race in __filemap_remove_folio / folio_mapping

write to 0xffffea000482de58 of 8 bytes by task 21824 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+0x27f/0xb60 mm/shmem.c:1145
 shmem_fallocate+0x84e/0x8f0 mm/shmem.c:3771
 vfs_fallocate+0x3ac/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+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffea000482de58 of 8 bytes by task 21823 on cpu 1:
 folio_mapping+0xa1/0xe0 mm/util.c:732
 folio_evictable mm/internal.h:584 [inline]
 evict_folios+0x2dd2/0x37d0 mm/vmscan.c:4864
 try_to_shrink_lruvec+0x7ac/0xb40 mm/vmscan.c:5009
 lru_gen_shrink_lruvec mm/vmscan.c:5173 [inline]
 shrink_lruvec+0x24e/0x1bc0 mm/vmscan.c:5932
 shrink_node_memcgs mm/vmscan.c:6171 [inline]
 shrink_node+0x699/0x2080 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+0x375/0xa00 mm/memcontrol.c:2630
 charge_memcg+0x6d/0x120 mm/memcontrol.c:5024
 __mem_cgroup_charge+0x28/0xb0 mm/memcontrol.c:5041
 mem_cgroup_charge include/linux/memcontrol.h:644 [inline]
 filemap_add_folio+0x110/0x350 mm/filemap.c:960
 page_cache_ra_unbounded+0x1a6/0x3b0 mm/readahead.c:282
 do_page_cache_ra mm/readahead.c:334 [inline]
 page_cache_ra_order+0x14a/0x210 mm/readahead.c:538
 do_sync_mmap_readahead+0x32a/0x340 mm/filemap.c:3417
 filemap_fault+0x359/0xb60 mm/filemap.c:3566
 __do_fault mm/memory.c:5474 [inline]
 do_shared_fault mm/memory.c:5973 [inline]
 do_fault mm/memory.c:6047 [inline]
 do_pte_missing mm/memory.c:4566 [inline]
 handle_pte_fault mm/memory.c:6427 [inline]
 __handle_mm_fault mm/memory.c:6565 [inline]
 handle_mm_fault+0x19a1/0x2da0 mm/memory.c:6734
 do_user_addr_fault+0x634/0x1060 arch/x86/mm/fault.c:1343
 handle_page_fault arch/x86/mm/fault.c:1483 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1536
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

value changed: 0xffff88811b68d7a8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 21823 Comm: syz.4.8031 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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