syzbot

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

write to 0xffff888237d26fd0 of 8 bytes by task 3326 on cpu 1:
 __invalidate_bh_lrus fs/buffer.c:1529 [inline]
 invalidate_bh_lru+0x8f/0xf0 fs/buffer.c:1541
 csd_do_func kernel/smp.c:136 [inline]
 smp_call_function_many_cond+0x88f/0xc60 kernel/smp.c:868
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1043
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1560
 invalidate_bdev+0x42/0x70 block/bdev.c:100
 ext4_put_super+0x624/0x7d0 fs/ext4/super.c:1348
 generic_shutdown_super+0xe6/0x210 fs/super.c:642
 kill_block_super+0x2a/0x70 fs/super.c:1722
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7403
 deactivate_locked_super+0x75/0x1c0 fs/super.c:473
 deactivate_super+0x97/0xa0 fs/super.c:506
 cleanup_mnt+0x269/0x2e0 fs/namespace.c:1327
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1334
 task_work_run+0x131/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xed/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d26fd0 of 8 bytes by task 3320 on cpu 0:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1551
 smp_call_function_many_cond+0x2a9/0xc60 kernel/smp.c:821
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1043
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1560
 invalidate_bdev+0x42/0x70 block/bdev.c:100
 ext4_put_super+0x624/0x7d0 fs/ext4/super.c:1348
 generic_shutdown_super+0xe6/0x210 fs/super.c:642
 kill_block_super+0x2a/0x70 fs/super.c:1722
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7403
 deactivate_locked_super+0x75/0x1c0 fs/super.c:473
 deactivate_super+0x97/0xa0 fs/super.c:506
 cleanup_mnt+0x269/0x2e0 fs/namespace.c:1327
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1334
 task_work_run+0x131/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xed/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888107563410 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3320 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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