syzbot

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BUG: KCSAN: data-race in __filemap_remove_folio / folio_mapping

write to 0xffffea000498b058 of 8 bytes by task 16836 on cpu 1:
 page_cache_delete mm/filemap.c:145 [inline]
 __filemap_remove_folio+0x201/0x2e0 mm/filemap.c:227
 filemap_remove_folio+0x6d/0x1d0 mm/filemap.c:257
 truncate_inode_folio+0x42/0x50 mm/truncate.c:176
 shmem_undo_range+0x27f/0xb60 mm/shmem.c:1145
 shmem_truncate_range mm/shmem.c:1277 [inline]
 shmem_evict_inode+0x132/0x520 mm/shmem.c:1407
 evict+0x2a5/0x510 fs/inode.c:825
 iput_final fs/inode.c:2019 [inline]
 iput+0x430/0x5a0 fs/inode.c:2068
 dentry_unlink_inode+0x24a/0x260 fs/dcache.c:479
 dentry_kill+0x184/0x500 fs/dcache.c:826
 finish_dput+0x16/0x1d0 fs/dcache.c:1001
 dput+0x48/0x50 fs/dcache.c:1042
 __fput+0x43e/0x630 fs/file_table.c:520
 ____fput+0x1c/0x30 fs/file_table.c:540
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x4a4/0x1500 kernel/exit.c:1004
 do_group_exit+0xfe/0x140 kernel/exit.c:1147
 get_signal+0xe07/0xf10 kernel/signal.c:3038
 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
 irqentry_exit+0x14d/0x610 kernel/entry/common.c:165
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

read to 0xffffea000498b058 of 8 bytes by task 16882 on cpu 0:
 folio_mapping+0xa1/0xe0 mm/util.c:732
 folio_evictable mm/internal.h:575 [inline]
 move_folios_to_lru+0x1f6/0x810 mm/vmscan.c:1882
 evict_folios+0x29ce/0x2d80 mm/vmscan.c:4865
 try_to_shrink_lruvec+0x7c5/0xb10 mm/vmscan.c:4983
 lru_gen_shrink_lruvec mm/vmscan.c:5128 [inline]
 shrink_lruvec+0x25e/0x1b60 mm/vmscan.c:5888
 shrink_node_memcgs mm/vmscan.c:6127 [inline]
 shrink_node+0x69d/0x20f0 mm/vmscan.c:6171
 shrink_zones mm/vmscan.c:6410 [inline]
 do_try_to_free_pages+0x408/0xc90 mm/vmscan.c:6472
 try_to_free_mem_cgroup_pages+0x201/0x420 mm/vmscan.c:6794
 try_charge_memcg+0x375/0xa00 mm/memcontrol.c:2655
 obj_cgroup_charge_pages mm/memcontrol.c:3097 [inline]
 __memcg_kmem_charge_page+0x199/0x3a0 mm/memcontrol.c:3141
 __alloc_frozen_pages_noprof+0x18a/0x350 mm/page_alloc.c:5321
 alloc_pages_mpol+0xa9/0x1d0 mm/mempolicy.c:2490
 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline]
 alloc_pages_noprof+0x8f/0x140 mm/mempolicy.c:2581
 vm_area_alloc_pages mm/vmalloc.c:3742 [inline]
 __vmalloc_area_node mm/vmalloc.c:3892 [inline]
 __vmalloc_node_range_noprof+0xae9/0x11e0 mm/vmalloc.c:4082
 __kvmalloc_node_noprof+0x3a0/0x590 mm/slub.c:6961
 futex_hash_allocate+0x192/0x920 kernel/futex/core.c:1823
 futex_hash_prctl+0xd8/0xf0 kernel/futex/core.c:1995
 __do_sys_prctl kernel/sys.c:2885 [inline]
 __se_sys_prctl+0x4f4/0x13b0 kernel/sys.c:2534
 __x64_sys_prctl+0x67/0x80 kernel/sys.c:2534
 x64_sys_call+0x2533/0x3020 arch/x86/include/generated/asm/syscalls_64.h:158
 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

value changed: 0xffff88811b7b41e8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 16882 Comm: syz.4.2831 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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