syzbot

EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
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BUG: KCSAN: data-race in __lru_add_drain_all / folios_put_refs

write to 0xffff888237c25a28 of 1 bytes by task 4397 on cpu 0:
 folio_batch_reinit include/linux/pagevec.h:50 [inline]
 folios_put_refs+0x272/0x2b0 mm/swap.c:988
 folios_put include/linux/mm.h:1551 [inline]
 folio_batch_move_lru+0x20b/0x230 mm/swap.c:175
 __folio_batch_add_and_move mm/swap.c:196 [inline]
 folio_add_lru+0x148/0x1f0 mm/swap.c:505
 shmem_alloc_and_add_folio mm/shmem.c:1961 [inline]
 shmem_get_folio_gfp+0x79e/0xd30 mm/shmem.c:2545
 shmem_fault+0xfd/0x270 mm/shmem.c:2746
 __do_fault+0xb6/0x200 mm/memory.c:4989
 do_read_fault mm/memory.c:5409 [inline]
 do_fault mm/memory.c:5543 [inline]
 do_pte_missing mm/memory.c:4059 [inline]
 handle_pte_fault mm/memory.c:5888 [inline]
 __handle_mm_fault mm/memory.c:6031 [inline]
 handle_mm_fault+0xe9a/0x2b10 mm/memory.c:6200
 faultin_page mm/gup.c:1196 [inline]
 __get_user_pages+0xf64/0x2350 mm/gup.c:1491
 populate_vma_page_range mm/gup.c:1929 [inline]
 __mm_populate+0x25d/0x3c0 mm/gup.c:2032
 mm_populate include/linux/mm.h:3392 [inline]
 vm_mmap_pgoff+0x224/0x2d0 mm/util.c:583
 ksys_mmap_pgoff+0xd0/0x340 mm/mmap.c:607
 x64_sys_call+0x1945/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c25a28 of 1 bytes by task 3314 on cpu 1:
 folio_batch_count include/linux/pagevec.h:56 [inline]
 cpu_needs_drain mm/swap.c:773 [inline]
 __lru_add_drain_all+0x136/0x3f0 mm/swap.c:867
 lru_add_drain_all+0x10/0x20 mm/swap.c:883
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x577/0x820 fs/ext4/super.c:1356
 generic_shutdown_super+0xe5/0x220 fs/super.c:642
 kill_block_super+0x2a/0x70 fs/super.c:1710
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7368
 deactivate_locked_super+0x7d/0x1c0 fs/super.c:473
 deactivate_super+0x9f/0xb0 fs/super.c:506
 cleanup_mnt+0x26e/0x2e0 fs/namespace.c:1435
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1442
 task_work_run+0x13c/0x1b0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x1f -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3314 Comm: syz-executor Not tainted 6.14.0-syzkaller-01103-g2df0c02dab82 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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