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BUG: KASAN: slab-out-of-bounds in __bpf_get_stackid+0x6bf/0x900 kernel/bpf/stackmap.c:271
Write of size 32 at addr ffff8880256ffed0 by task syz.1.468/7966

CPU: 0 PID: 7966 Comm: syz.1.468 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x288/0x290 mm/kasan/generic.c:187
 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106
 __bpf_get_stackid+0x6bf/0x900 kernel/bpf/stackmap.c:271
 ____bpf_get_stackid_raw_tp kernel/trace/bpf_trace.c:1892 [inline]
 bpf_get_stackid_raw_tp+0x196/0x200 kernel/trace/bpf_trace.c:1881
 bpf_prog_e95a4a16f042d2d7+0x29/0x2d
 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
 __bpf_prog_run include/linux/filter.h:605 [inline]
 bpf_prog_run include/linux/filter.h:619 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
 bpf_trace_run10+0x3a2/0x450 kernel/trace/bpf_trace.c:2369
 __bpf_trace_percpu_alloc_percpu+0x365/0x3f0 include/trace/events/percpu.h:11
 trace_percpu_alloc_percpu include/trace/events/percpu.h:11 [inline]
 pcpu_alloc+0x1747/0x18d0 mm/percpu.c:1880
 pcpu_freelist_init+0x33/0x1e0 kernel/bpf/percpu_freelist.c:10
 prealloc_elems_and_freelist+0xbd/0x1c0 kernel/bpf/stackmap.c:56
 stack_map_alloc+0x33a/0x4c0 kernel/bpf/stackmap.c:114
 map_create+0x877/0x1110 kernel/bpf/syscall.c:1245
 __sys_bpf+0x5f0/0x800 kernel/bpf/syscall.c:5449
 __do_sys_bpf kernel/bpf/syscall.c:5571 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5569 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5569
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0c8c18ebe9
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:00007f0c8d06e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f0c8c3b5fa0 RCX: 00007f0c8c18ebe9
RDX: 0000000000000048 RSI: 0000200000000280 RDI: 0000000000000000
RBP: 00007f0c8c211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c8c3b6038 R14: 00007f0c8c3b5fa0 R15: 00007ffcd6913868
 </TASK>

Allocated by task 7960:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc_node+0xb4/0x230 mm/slab_common.c:1014
 kmalloc_node include/linux/slab.h:620 [inline]
 __bpf_map_area_alloc kernel/bpf/syscall.c:301 [inline]
 bpf_map_area_alloc+0x5e/0x110 kernel/bpf/syscall.c:314
 prealloc_elems_and_freelist+0x86/0x1c0 kernel/bpf/stackmap.c:51
 stack_map_alloc+0x33a/0x4c0 kernel/bpf/stackmap.c:114
 map_create+0x877/0x1110 kernel/bpf/syscall.c:1245
 __sys_bpf+0x5f0/0x800 kernel/bpf/syscall.c:5449
 __do_sys_bpf kernel/bpf/syscall.c:5571 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5569 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5569
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff8880256ffec0
 which belongs to the cache kmalloc-cg-32 of size 32
The buggy address is located 16 bytes inside of
 allocated 24-byte region [ffff8880256ffec0, ffff8880256ffed8)

The buggy address belongs to the physical page:
page:ffffea000095bfc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880256ff980 pfn:0x256ff
memcg:ffff88802326a801
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff88801784d8c0 ffffea0000c067c0 0000000000000004
raw: ffff8880256ff980 000000008040003c 00000001ffffffff ffff88802326a801
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 5574, tgid 5574 (dhcpcd-run-hook), ts 59944841388, free_ts 49219822964
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 alloc_slab_page+0x5d/0x170 mm/slub.c:1876
 allocate_slab mm/slub.c:2023 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2076
 ___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230
 __slab_alloc mm/slub.c:3329 [inline]
 __slab_alloc_node mm/slub.c:3382 [inline]
 slab_alloc_node mm/slub.c:3475 [inline]
 __kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3524
 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 single_open+0x5a/0x240 fs/seq_file.c:575
 proc_reg_open+0x242/0x530 fs/proc/inode.c:532
 do_dentry_open+0x8c6/0x1500 fs/open.c:929
 do_open fs/namei.c:3632 [inline]
 path_openat+0x274b/0x3190 fs/namei.c:3789
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_openat fs/open.c:1450 [inline]
 __se_sys_openat fs/open.c:1445 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1445
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475
 release_pages+0x1fa0/0x2220 mm/swap.c:1022
 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
 tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392
 exit_mmap+0x3f0/0xb50 mm/mmap.c:3311
 __mmput+0x118/0x3c0 kernel/fork.c:1355
 exit_mm+0x1da/0x2c0 kernel/exit.c:569
 do_exit+0x88e/0x23c0 kernel/exit.c:870
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 __do_sys_exit_group kernel/exit.c:1035 [inline]
 __se_sys_exit_group kernel/exit.c:1033 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff8880256ffd80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880256ffe00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880256ffe80: fa fb fb fb fc fc fc fc 00 00 00 fc fc fc fc fc
                                                    ^
 ffff8880256fff00: fa fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880256fff80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
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