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BUG: KASAN: out-of-bounds in user_mode arch/x86/include/asm/ptrace.h:136 [inline]
BUG: KASAN: out-of-bounds in update_stack_state+0x32f/0x490 arch/x86/kernel/unwind_frame.c:248
Read of size 8 at addr ffffc9000364f700 by task syz.5.17827/23460

CPU: 0 PID: 23460 Comm: syz.5.17827 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:351
 user_mode arch/x86/include/asm/ptrace.h:136 [inline]
 update_stack_state+0x32f/0x490 arch/x86/kernel/unwind_frame.c:248
 unwind_next_frame+0x39e/0x660 arch/x86/kernel/unwind_frame.c:315
 arch_stack_walk+0x124/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save_tsk+0x16d/0x210 kernel/stacktrace.c:150
 proc_pid_stack+0x133/0x1f0 fs/proc/base.c:506
 proc_single_show+0x10d/0x1a0 fs/proc/base.c:827
 traverse+0x215/0x5e0 fs/seq_file.c:111
 seq_read_iter+0xc68/0xd80 fs/seq_file.c:195
 seq_read+0x171/0x210 fs/seq_file.c:162
 vfs_read+0x286/0x930 fs/read_write.c:468
 ksys_pread64 fs/read_write.c:665 [inline]
 __do_sys_pread64 fs/read_write.c:675 [inline]
 __se_sys_pread64 fs/read_write.c:672 [inline]
 __x64_sys_pread64+0x194/0x220 fs/read_write.c:672
 x64_sys_call+0x4c7/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:18
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f096319f559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f096409b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007f0963425fa0 RCX: 00007f096319f559
RDX: 000000000000000f RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007f0963236b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0963426038 R14: 00007f0963425fa0 R15: 00007ffea538b1e8
 </TASK>

The buggy address belongs to a 8-page vmalloc region starting at 0xffffc90003648000 allocated at copy_process+0x5e7/0x3500 kernel/fork.c:2315
The buggy address belongs to the physical page:
page:ffffea00047f5f40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11fd7d
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 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 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 23442, tgid 23442 (syz.5.17826), ts 320868834038, free_ts 320822829204
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2673
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2680
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4587
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5931
 vm_area_alloc_pages mm/vmalloc.c:-1 [inline]
 __vmalloc_area_node mm/vmalloc.c:3084 [inline]
 __vmalloc_node_range+0x8ca/0x1440 mm/vmalloc.c:3256
 alloc_thread_stack_node kernel/fork.c:322 [inline]
 dup_task_struct+0x3ca/0x900 kernel/fork.c:1086
 copy_process+0x5e7/0x3500 kernel/fork.c:2315
 kernel_clone+0x22f/0x7f0 kernel/fork.c:2903
 __do_sys_clone3 kernel/fork.c:3204 [inline]
 __se_sys_clone3 kernel/fork.c:3188 [inline]
 __x64_sys_clone3+0x2ce/0x360 kernel/fork.c:3188
 x64_sys_call+0x4ce/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:436
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1581 [inline]
 free_pcp_prepare mm/page_alloc.c:1655 [inline]
 free_unref_page_prepare+0x81b/0x820 mm/page_alloc.c:3622
 free_unref_page_list+0x117/0x8d0 mm/page_alloc.c:3773
 release_pages+0xc7e/0xce0 mm/swap.c:1053
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:316
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu mm/mmu_gather.c:261 [inline]
 tlb_finish_mmu+0x1b2/0x380 mm/mmu_gather.c:361
 exit_mmap+0x41d/0xc10 mm/mmap.c:3384
 __mmput+0x92/0x340 kernel/fork.c:1321
 mmput+0x4b/0x150 kernel/fork.c:1345
 exit_mm kernel/exit.c:575 [inline]
 do_exit+0xa62/0x29f0 kernel/exit.c:883
 do_group_exit+0x21b/0x2e0 kernel/exit.c:1040
 get_signal+0x167c/0x1700 kernel/signal.c:2904
 arch_do_signal_or_restart+0xd1/0x11c0 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x7a/0xb0 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82

Memory state around the buggy address:
 ffffc9000364f600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000364f680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9000364f700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                      ^
 ffffc9000364f780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000364f800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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