syzbot

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BUG: KCSAN: data-race in __filemap_remove_folio / folio_mapping

write to 0xffffea0004246818 of 8 bytes by task 23211 on cpu 1:
 page_cache_delete mm/filemap.c:145 [inline]
 __filemap_remove_folio+0x1a5/0x2a0 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+0x244/0xa80 mm/shmem.c:1133
 shmem_truncate_range mm/shmem.c:1249 [inline]
 shmem_evict_inode+0x12e/0x510 mm/shmem.c:1379
 evict+0x2af/0x510 fs/inode.c:837
 iput_final fs/inode.c:1951 [inline]
 iput+0x4bd/0x650 fs/inode.c:2003
 dentry_unlink_inode+0x24f/0x260 fs/dcache.c:467
 __dentry_kill+0x18d/0x4b0 fs/dcache.c:670
 finish_dput+0x2b/0x200 fs/dcache.c:879
 dput+0x52/0x60 fs/dcache.c:928
 __fput+0x444/0x650 fs/file_table.c:476
 ____fput+0x1c/0x30 fs/file_table.c:496
 task_work_run+0x131/0x1a0 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x493/0x15d0 kernel/exit.c:971
 do_group_exit+0xff/0x140 kernel/exit.c:1112
 get_signal+0xe58/0xf70 kernel/signal.c:3034
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:75 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0xfb/0x560 kernel/entry/common.c:196
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffffea0004246818 of 8 bytes by task 23313 on cpu 0:
 folio_mapping+0xa1/0xe0 mm/util.c:703
 folio_evictable mm/internal.h:499 [inline]
 sort_folio mm/vmscan.c:4444 [inline]
 scan_folios mm/vmscan.c:4571 [inline]
 isolate_folios mm/vmscan.c:4667 [inline]
 evict_folios+0xe05/0x3590 mm/vmscan.c:4697
 try_to_shrink_lruvec+0x5b5/0x950 mm/vmscan.c:4872
 lru_gen_shrink_lruvec mm/vmscan.c:5021 [inline]
 shrink_lruvec+0x22e/0x1b50 mm/vmscan.c:5782
 shrink_node_memcgs mm/vmscan.c:6018 [inline]
 shrink_node+0x66c/0x2010 mm/vmscan.c:6059
 shrink_zones mm/vmscan.c:6298 [inline]
 do_try_to_free_pages+0x3f6/0xcd0 mm/vmscan.c:6360
 try_to_free_mem_cgroup_pages+0x1ab/0x410 mm/vmscan.c:6688
 try_charge_memcg+0x383/0xa10 mm/memcontrol.c:2388
 obj_cgroup_charge_pages+0xa6/0x150 mm/memcontrol.c:2823
 __memcg_kmem_charge_page+0x9f/0x170 mm/memcontrol.c:2867
 __alloc_frozen_pages_noprof+0x18f/0x360 mm/page_alloc.c:5227
 alloc_pages_mpol+0xb3/0x260 mm/mempolicy.c:2486
 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
 alloc_pages_noprof+0x90/0x130 mm/mempolicy.c:2577
 io_mem_alloc_compound io_uring/memmap.c:30 [inline]
 io_region_allocate_pages+0xd8/0x330 io_uring/memmap.c:165
 io_create_region+0x2b2/0x330 io_uring/memmap.c:220
 io_allocate_scq_urings+0x248/0x390 io_uring/io_uring.c:3392
 io_uring_create+0x2d4/0x4e0 io_uring/io_uring.c:3643
 io_uring_setup io_uring/io_uring.c:3718 [inline]
 __do_sys_io_uring_setup io_uring/io_uring.c:3752 [inline]
 __se_sys_io_uring_setup+0x1be/0x1d0 io_uring/io_uring.c:3743
 __x64_sys_io_uring_setup+0x31/0x40 io_uring/io_uring.c:3743
 x64_sys_call+0x244c/0x3000 arch/x86/include/generated/asm/syscalls_64.h:426
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff8881061d7ef8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 23313 Comm: syz.1.4571 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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