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BUG: KASAN: stack-out-of-bounds in user_mode arch/x86/include/asm/ptrace.h:214 [inline]
BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x1cb0/0x2390 arch/x86/kernel/unwind_orc.c:482
Read of size 2 at addr ffffc90004fcf9b0 by task syz.2.382/7149

CPU: 0 UID: 0 PID: 7149 Comm: syz.2.382 Not tainted 6.16.0-syzkaller-00857-gced1b9e0392d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 user_mode arch/x86/include/asm/ptrace.h:214 [inline]
 unwind_next_frame+0x1cb0/0x2390 arch/x86/kernel/unwind_orc.c:482
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save_tsk+0x15f/0x200 kernel/stacktrace.c:150
 proc_pid_stack+0x12c/0x1f0 fs/proc/base.c:492
 proc_single_show+0xfb/0x1c0 fs/proc/base.c:812
 traverse+0x1e9/0x570 fs/seq_file.c:111
 seq_read_iter+0xcfe/0xe10 fs/seq_file.c:195
 seq_read+0x2e2/0x3d0 fs/seq_file.c:162
 vfs_read+0x200/0x980 fs/read_write.c:570
 ksys_pread64 fs/read_write.c:763 [inline]
 __do_sys_pread64 fs/read_write.c:771 [inline]
 __se_sys_pread64 fs/read_write.c:768 [inline]
 __x64_sys_pread64+0x193/0x220 fs/read_write.c:768
 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
RIP: 0033:0x7f7bb218e9a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7bb2f9c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007f7bb23b6080 RCX: 00007f7bb218e9a9
RDX: 0000000000000003 RSI: 0000200000000280 RDI: 0000000000000004
RBP: 00007f7bb2210d69 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000fffffffa R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7bb23b6080 R15: 00007ffcbc9a8498
 </TASK>

The buggy address belongs to a vmalloc virtual mapping
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffffffffffffffff pfn:0x33cb1
memcg:ffff888028331e82
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffffffffffffffff 0000000000000000 00000001ffffffff ffff888028331e82
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 7032, tgid 7032 (syz.4.345), ts 149732988298, free_ts 148916672805
 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:3642 [inline]
 __vmalloc_area_node mm/vmalloc.c:3720 [inline]
 __vmalloc_node_range_noprof+0x97d/0x12f0 mm/vmalloc.c:3893
 __vmalloc_node_noprof+0xc2/0x110 mm/vmalloc.c:3956
 alloc_thread_stack_node kernel/fork.c:317 [inline]
 dup_task_struct+0x3e7/0x860 kernel/fork.c:877
 copy_process+0x544/0x3b80 kernel/fork.c:1999
 kernel_clone+0x21e/0x870 kernel/fork.c:2599
 __do_sys_clone3 kernel/fork.c:2903 [inline]
 __se_sys_clone3+0x256/0x2d0 kernel/fork.c:2882
 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 5937 tgid 5937 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:2884 [inline]
 pagetable_dtor_free include/linux/mm.h:2982 [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
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 napi_threaded_poll_loop+0x50e/0x6c0 net/core/dev.c:7546
 napi_threaded_poll+0x1be/0x2b0 net/core/dev.c:7561
 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

Memory state around the buggy address:
 ffffc90004fcf880: 00 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004fcf900: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
>ffffc90004fcf980: 00 00 00 00 00 f2 f2 f2 f2 f2 00 00 f2 f2 00 f2
                                     ^
 ffffc90004fcfa00: f2 f2 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
 ffffc90004fcfa80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
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