syzbot

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BUG: KCSAN: data-race in __filemap_remove_folio / folio_mapping

write to 0xffffea0005594798 of 8 bytes by task 17182 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:257
 truncate_inode_folio+0x42/0x50 mm/truncate.c:176
 shmem_undo_range+0x26d/0xb10 mm/shmem.c:1145
 shmem_truncate_range mm/shmem.c:1277 [inline]
 shmem_evict_inode+0x12e/0x540 mm/shmem.c:1407
 evict+0x2af/0x510 fs/inode.c:841
 iput_final fs/inode.c:1960 [inline]
 iput+0x41a/0x580 fs/inode.c:2009
 dentry_unlink_inode+0x24f/0x260 fs/dcache.c:467
 __dentry_kill+0x13f/0x460 fs/dcache.c:670
 finish_dput+0x2b/0x200 fs/dcache.c:879
 dput+0x52/0x60 fs/dcache.c:928
 __fput+0x444/0x630 fs/file_table.c:518
 ____fput+0x1c/0x30 fs/file_table.c:538
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x4ae/0x1530 kernel/exit.c:977
 do_group_exit+0xfe/0x140 kernel/exit.c:1119
 get_signal+0xe30/0xf20 kernel/signal.c:3039
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:98 [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:252 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:323 [inline]
 irqentry_exit+0x140/0x5b0 kernel/entry/common.c:162
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffffea0005594798 of 8 bytes by task 17415 on cpu 1:
 folio_mapping+0xa1/0xe0 mm/util.c:732
 folio_evictable mm/internal.h:585 [inline]
 sort_folio mm/vmscan.c:4463 [inline]
 scan_folios mm/vmscan.c:4590 [inline]
 isolate_folios mm/vmscan.c:4682 [inline]
 evict_folios+0xdbe/0x33b0 mm/vmscan.c:4712
 try_to_shrink_lruvec+0x81b/0xbf0 mm/vmscan.c:4885
 lru_gen_shrink_lruvec mm/vmscan.c:5034 [inline]
 shrink_lruvec+0x265/0x1b70 mm/vmscan.c:5793
 shrink_node_memcgs mm/vmscan.c:6032 [inline]
 shrink_node+0x699/0x2100 mm/vmscan.c:6076
 shrink_zones mm/vmscan.c:6315 [inline]
 do_try_to_free_pages+0x408/0xc90 mm/vmscan.c:6377
 try_to_free_mem_cgroup_pages+0x201/0x420 mm/vmscan.c:6699
 try_charge_memcg+0x373/0xa10 mm/memcontrol.c:2439
 obj_cgroup_charge_pages mm/memcontrol.c:2882 [inline]
 __memcg_kmem_charge_page+0x139/0x2b0 mm/memcontrol.c:2926
 __alloc_frozen_pages_noprof+0x18a/0x350 mm/page_alloc.c:5245
 alloc_pages_mpol+0xb3/0x260 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:3728 [inline]
 __vmalloc_area_node mm/vmalloc.c:3878 [inline]
 __vmalloc_node_range_noprof+0xaed/0x11c0 mm/vmalloc.c:4064
 __kvmalloc_node_noprof+0x3d4/0x640 mm/slub.c:6856
 futex_hash_allocate+0x190/0x9a0 kernel/futex/core.c:1815
 futex_hash_prctl+0xd8/0xf0 kernel/futex/core.c:1961
 __do_sys_prctl kernel/sys.c:2885 [inline]
 __se_sys_prctl+0x4f4/0x1400 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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88811bc51f70 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 17415 Comm: syz.0.6822 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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