==================================================================
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+0xc3/0xe0 fs/buffer.c:161
Write of size 4 at addr ffffc900032c7700 by task kworker/u8:14/6161

CPU: 0 UID: 0 PID: 6161 Comm: kworker/u8:14 Not tainted 6.16.0-rc2-syzkaller-00082-gfb4d33ab452e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: loop5 loop_workfn
Call Trace:
 <IRQ>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 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+0xc3/0xe0 fs/buffer.c:161
 end_bio_bh_io_sync+0xbd/0x120 fs/buffer.c:2783
 blk_update_request+0x5eb/0xe70 block/blk-mq.c:987
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1149
 blk_complete_reqs block/blk-mq.c:1224 [inline]
 blk_done_softirq+0x10a/0x160 block/blk-mq.c:1229
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline]
 sysvec_call_function_single+0xa3/0xc0 arch/x86/kernel/smp.c:266
 </IRQ>
 <TASK>
 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:raise_softirq+0xcc/0x120 kernel/softirq.c:741
Code: 35 42 00 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 49 41 f7 c4 00 02 00 00 74 01 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 66 43 c7 44 3e 09 00 00 43 c6 44 3e 0b 00
RSP: 0018:ffffc9000b727400 EFLAGS: 00000206
RAX: 37aed7246ed54600 RBX: 0000000000000004 RCX: 37aed7246ed54600
RDX: 0000000000000006 RSI: ffffffff8d9823c9 RDI: ffffffff8be28b80
RBP: ffffc9000b7274b0 R08: ffffffff8fa10df7 R09: 1ffffffff1f421be
R10: dffffc0000000000 R11: fffffbfff1f421bf R12: 0000000000000212
R13: 1ffff920016e4e9c R14: 1ffff920016e4e80 R15: dffffc0000000000
 blk_mq_raise_softirq block/blk-mq.c:1286 [inline]
 blk_mq_complete_request_remote+0x6f7/0xa50 block/blk-mq.c:1310
 blk_mq_complete_request+0x19/0xa0 block/blk-mq.c:1326
 lo_rw_aio_complete drivers/block/loop.c:328 [inline]
 lo_rw_aio+0xe0b/0x1040 drivers/block/loop.c:402
 do_req_filebacked drivers/block/loop.c:-1 [inline]
 loop_handle_cmd drivers/block/loop.c:1889 [inline]
 loop_process_work+0x810/0xf40 drivers/block/loop.c:1924
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 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
 [ffffc900032c0000, ffffc900032c9000) created by:
 copy_process+0x54b/0x3c00 kernel/fork.c:1999

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888000000000 pfn:0x66e93
memcg:ffff888027c18102
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff888000000000 0000000000000000 00000001ffffffff ffff888027c18102
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_ZERO|__GFP_NOWARN), pid 9301, tgid 9301 (syz-executor), ts 692520141527, free_ts 692121773434
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 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+0xa9/0x190 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+0x97d/0x12f0 mm/vmalloc.c:3885
 __vmalloc_node_noprof+0xc2/0x110 mm/vmalloc.c:3948
 alloc_thread_stack_node kernel/fork.c:317 [inline]
 dup_task_struct+0x3e7/0x860 kernel/fork.c:877
 copy_process+0x54b/0x3c00 kernel/fork.c:1999
 kernel_clone+0x21e/0x870 kernel/fork.c:2599
 __do_sys_clone kernel/fork.c:2742 [inline]
 __se_sys_clone kernel/fork.c:2726 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2726
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 9301 tgid 9301 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc71/0xe70 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+0x2d2/0x3b0 include/asm-generic/tlb.h:220
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:290
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 rcu_core+0xca8/0x1710 kernel/rcu/tree.c:2832
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 do_softirq+0xec/0x180 kernel/softirq.c:480
 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407
 do_ip_getsockopt+0x10b6/0x1b60 net/ipv4/ip_sockglue.c:1703
 ip_getsockopt+0xbb/0x220 net/ipv4/ip_sockglue.c:1765
 do_sock_getsockopt+0x360/0x650 net/socket.c:2357
 __sys_getsockopt net/socket.c:2386 [inline]
 __do_sys_getsockopt net/socket.c:2393 [inline]
 __se_sys_getsockopt net/socket.c:2390 [inline]
 __x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2390
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffffc900032c7600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900032c7680: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
>ffffc900032c7700: 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 00 f2 f2 f2
                      ^
 ffffc900032c7780: 01 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc900032c7800: 00 00 00 00 f1 f1 f1 f1 00 f3 f3 f3 00 00 00 00
==================================================================
vkms_vblank_simulate: vblank timer overrun
----------------
Code disassembly (best guess):
   0:	35 42 00 48 c7       	xor    $0xc7480042,%eax
   5:	44 24 20             	rex.R and $0x20,%al
   8:	00 00                	add    %al,(%rax)
   a:	00 00                	add    %al,(%rax)
   c:	9c                   	pushf
   d:	8f 44 24 20          	pop    0x20(%rsp)
  11:	f6 44 24 21 02       	testb  $0x2,0x21(%rsp)
  16:	75 49                	jne    0x61
  18:	41 f7 c4 00 02 00 00 	test   $0x200,%r12d
  1f:	74 01                	je     0x22
  21:	fb                   	sti
  22:	48 c7 04 24 0e 36 e0 	movq   $0x45e0360e,(%rsp)
  29:	45
* 2a:	4b c7 04 3e 00 00 00 	movq   $0x0,(%r14,%r15,1) <-- trapping instruction
  31:	00
  32:	66 43 c7 44 3e 09 00 	movw   $0x0,0x9(%r14,%r15,1)
  39:	00
  3a:	43 c6 44 3e 0b 00    	movb   $0x0,0xb(%r14,%r15,1)