==================================================================
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 ffffc90003fbf720 by task ksoftirqd/0/15
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted 6.15.0-rc5-syzkaller-00136-g9c69f8884904 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0xb4/0x290 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+0x29a/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+0xc3/0xe0 fs/buffer.c:161
end_bio_bh_io_sync+0xbd/0x120 fs/buffer.c:2783
blk_update_request+0x5ee/0xe80 block/blk-mq.c:983
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1145
blk_complete_reqs block/blk-mq.c:1220 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1225
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
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5250
Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 e9 27 05 00 00 4c 8b 75 d0 4c 89 e7 e8 7f a2 c6 09 e8 2a 66 35 00 fb 4c 8b 65 c0 <49> 8d bc 24 18 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90000147ad8 EFLAGS: 00000286
RAX: 6b04af7d68156000 RBX: 0000000000000000 RCX: 6b04af7d68156000
RDX: 0000000000000000 RSI: ffffffff8d74ab7a RDI: ffffffff8bc1d260
RBP: ffffc90000147b30 R08: ffffffff8f7ed177 R09: 1ffffffff1efda2e
R10: dffffc0000000000 R11: fffffbfff1efda2f R12: ffff88801b683c00
R13: dffffc0000000000 R14: ffff88802f60da00 R15: ffff8880b883a6d8
context_switch kernel/sched/core.c:5385 [inline]
__schedule+0x16ea/0x4cd0 kernel/sched/core.c:6767
__schedule_loop kernel/sched/core.c:6845 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6860
smpboot_thread_fn+0x5bd/0xa60 kernel/smpboot.c:160
kthread+0x711/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
The buggy address belongs to the virtual mapping at
[ffffc90003fb8000, ffffc90003fc1000) created by:
copy_process+0x544/0x3b80 kernel/fork.c:2259
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x1fe pfn:0x1bfe7
memcg:ffff8880263dfe82
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 00000000000001fe 0000000000000000 00000001ffffffff ffff8880263dfe82
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 19834, tgid 19834 (syz.7.2771), ts 1825492057062, free_ts 1825419760253
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1d8/0x230 mm/page_alloc.c:1718
prep_new_page mm/page_alloc.c:1726 [inline]
get_page_from_freelist+0x21ce/0x22b0 mm/page_alloc.c:3688
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4970
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301
alloc_frozen_pages_noprof mm/mempolicy.c:2372 [inline]
alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2392
vm_area_alloc_pages mm/vmalloc.c:3591 [inline]
__vmalloc_area_node mm/vmalloc.c:3669 [inline]
__vmalloc_node_range_noprof+0x8fe/0x12c0 mm/vmalloc.c:3844
__vmalloc_node_noprof+0x7d/0x90 mm/vmalloc.c:3907
alloc_thread_stack_node kernel/fork.c:314 [inline]
dup_task_struct+0x3e7/0x860 kernel/fork.c:1136
copy_process+0x544/0x3b80 kernel/fork.c:2259
kernel_clone+0x21e/0x870 kernel/fork.c:2844
__do_sys_clone3 kernel/fork.c:3148 [inline]
__se_sys_clone3+0x256/0x2d0 kernel/fork.c:3127
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 23 tgid 23 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1262 [inline]
__free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725
pagetable_free include/linux/mm.h:3019 [inline]
pagetable_dtor_free include/linux/mm.h:3117 [inline]
__tlb_remove_table+0x2d2/0x3b0 include/asm-generic/tlb.h:215
__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:2568 [inline]
rcu_core+0xca8/0x1710 kernel/rcu/tree.c:2824
handle_softirqs+0x286/0x870 kernel/softirq.c:579
run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968
smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:164
kthread+0x711/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Memory state around the buggy address:
ffffc90003fbf600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc90003fbf680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90003fbf700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffffc90003fbf780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc90003fbf800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
vkms_vblank_simulate: vblank timer overrun
----------------
Code disassembly (best guess):
0: 0f 84 3c 01 00 00 je 0x142
6: 48 85 db test %rbx,%rbx
9: 0f 85 63 01 00 00 jne 0x172
f: e9 27 05 00 00 jmp 0x53b
14: 4c 8b 75 d0 mov -0x30(%rbp),%r14
18: 4c 89 e7 mov %r12,%rdi
1b: e8 7f a2 c6 09 call 0x9c6a29f
20: e8 2a 66 35 00 call 0x35664f
25: fb sti
26: 4c 8b 65 c0 mov -0x40(%rbp),%r12
* 2a: 49 8d bc 24 18 16 00 lea 0x1618(%r12),%rdi <-- trapping instruction
31: 00
32: 48 89 f8 mov %rdi,%rax
35: 48 c1 e8 03 shr $0x3,%rax
39: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax
3e: 84 c0 test %al,%al