==================================================================
BUG: KASAN: out-of-bounds in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: out-of-bounds in atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]
BUG: KASAN: out-of-bounds in put_bh include/linux/buffer_head.h:304 [inline]
BUG: KASAN: out-of-bounds in end_buffer_read_sync+0xbf/0xd0 fs/buffer.c:161
Write of size 4 at addr ffffc9000b97e4c0 by task kworker/u8:3/37

CPU: 0 UID: 0 PID: 37 Comm: kworker/u8:3 Not tainted 6.16.0-rc3-syzkaller-00044-g7595b66ae9de #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: loop2 loop_workfn
Call Trace:
 <IRQ>
 dump_stack_lvl+0x185/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc2/0x2a0 mm/kasan/report.c:521
 kasan_report+0x114/0x150 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2a4/0x2b0 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline]
 put_bh include/linux/buffer_head.h:304 [inline]
 end_buffer_read_sync+0xbf/0xd0 fs/buffer.c:161
 end_bio_bh_io_sync+0xb9/0x110 fs/buffer.c:2783
 blk_update_request+0x5e7/0xe70 block/blk-mq.c:987
 blk_mq_end_request+0x3a/0x70 block/blk-mq.c:1149
 blk_complete_reqs block/blk-mq.c:1224 [inline]
 blk_done_softirq+0x103/0x160 block/blk-mq.c:1229
 handle_softirqs+0x27f/0x850 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xc6/0x1e0 kernel/softirq.c:680
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:696
 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
 sysvec_call_function_single+0x9d/0xc0 arch/x86/kernel/smp.c:266
 </IRQ>
 <TASK>
 asm_sysvec_call_function_single+0x16/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x50 kernel/locking/spinlock.c:202
Code: 90 90 90 90 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 3e a8 a0 f6 48 89 df e8 46 25 a1 f6 e8 21 f7 c9 f6 fb bf 01 00 00 00 <e8> 16 2b 93 f6 65 8b 05 5f 05 f8 06 85 c0 74 07 5b e9 c5 4b 00 00
RSP: 0018:ffffc90000ad7730 EFLAGS: 00000286
RAX: 36bd67387e08e100 RBX: ffff8881427b90c8 RCX: 36bd67387e08e100
RDX: 0000000000000006 RSI: ffffffff8d0a740a RDI: 0000000000000001
RBP: ffffc90000ad7a50 R08: ffffffff8f131af7 R09: 1ffffffff1e2635e
R10: dffffc0000000000 R11: fffffbfff1e2635f R12: ffff888025704a78
R13: dffffc0000000000 R14: ffff8881427b9168 R15: ffff8881427b9180
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 loop_process_work+0xe74/0xf40 drivers/block/loop.c:1940
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadd/0x1780 kernel/workqueue.c:3321
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3402
 kthread+0x70d/0x890 kernel/kthread.c:464
 ret_from_fork+0x3f1/0x750 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

The buggy address belongs to the virtual mapping at
 [ffffc9000b978000, ffffc9000b981000) created by:
 copy_process+0x547/0x3bf0 kernel/fork.c:1999

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5c7de
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO|__GFP_NOWARN), pid 7216, tgid 7216 (syz.2.175), ts 218353558025, free_ts 215403036303
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x230/0x280 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x2b2b/0x2ce0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x17d/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_frozen_pages_noprof mm/mempolicy.c:2490 [inline]
 alloc_pages_noprof+0xa5/0x190 mm/mempolicy.c:2510
 vm_area_alloc_pages mm/vmalloc.c:3634 [inline]
 __vmalloc_area_node mm/vmalloc.c:3712 [inline]
 __vmalloc_node_range_noprof+0x979/0x12e0 mm/vmalloc.c:3885
 __vmalloc_node_noprof+0xbe/0x100 mm/vmalloc.c:3948
 alloc_thread_stack_node kernel/fork.c:317 [inline]
 dup_task_struct+0x3e7/0x860 kernel/fork.c:877
 copy_process+0x547/0x3bf0 kernel/fork.c:1999
 kernel_clone+0x21a/0x860 kernel/fork.c:2599
 __do_sys_clone3 kernel/fork.c:2903 [inline]
 __se_sys_clone3+0x252/0x2c0 kernel/fork.c:2882
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x86/0x2e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
page last free pid 6426 tgid 6426 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc4f/0xe40 mm/page_alloc.c:2706
 pagetable_free include/linux/mm.h:2879 [inline]
 pagetable_dtor_free include/linux/mm.h:2977 [inline]
 __tlb_remove_table+0x2ce/0x3a0 include/asm-generic/tlb.h:220
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x81/0x100 mm/mmu_gather.c:290
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 rcu_core+0xc98/0x16e0 kernel/rcu/tree.c:2832
 handle_softirqs+0x27f/0x850 kernel/softirq.c:579
 do_softirq+0xe8/0x180 kernel/softirq.c:480
 __local_bh_enable_ip+0x177/0x1c0 kernel/softirq.c:407
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 srcu_invoke_callbacks+0x211/0x440 kernel/rcu/srcutree.c:1806
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadd/0x1780 kernel/workqueue.c:3321
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3402
 kthread+0x70d/0x890 kernel/kthread.c:464
 ret_from_fork+0x3f1/0x750 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffffc9000b97e380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000b97e400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9000b97e480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                              ^
 ffffc9000b97e500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000b97e580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	90                   	nop
   2:	90                   	nop
   3:	90                   	nop
   4:	90                   	nop
   5:	53                   	push   %rbx
   6:	48 89 fb             	mov    %rdi,%rbx
   9:	48 83 c7 18          	add    $0x18,%rdi
   d:	48 8b 74 24 08       	mov    0x8(%rsp),%rsi
  12:	e8 3e a8 a0 f6       	call   0xf6a0a855
  17:	48 89 df             	mov    %rbx,%rdi
  1a:	e8 46 25 a1 f6       	call   0xf6a12565
  1f:	e8 21 f7 c9 f6       	call   0xf6c9f745
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
* 2a:	e8 16 2b 93 f6       	call   0xf6932b45 <-- trapping instruction
  2f:	65 8b 05 5f 05 f8 06 	mov    %gs:0x6f8055f(%rip),%eax        # 0x6f80595
  36:	85 c0                	test   %eax,%eax
  38:	74 07                	je     0x41
  3a:	5b                   	pop    %rbx
  3b:	e9 c5 4b 00 00       	jmp    0x4c05