================================================================== BUG: KASAN: slab-out-of-bounds in __bpf_get_stackid+0x6c9/0x920 kernel/bpf/stackmap.c:274 Write of size 56 at addr ffff88807959c290 by task syz.4.9188/31656 CPU: 0 PID: 31656 Comm: syz.4.9188 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x235/0x290 mm/kasan/generic.c:189 memcpy+0x3c/0x60 mm/kasan/shadow.c:66 __bpf_get_stackid+0x6c9/0x920 kernel/bpf/stackmap.c:274 ____bpf_get_stackid_pe kernel/bpf/stackmap.c:365 [inline] bpf_get_stackid_pe+0x33f/0x400 kernel/bpf/stackmap.c:334 bpf_prog_ceda4e53fcf21ae1+0x28/0x40 bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline] __bpf_prog_run include/linux/filter.h:607 [inline] bpf_prog_run include/linux/filter.h:614 [inline] bpf_overflow_handler+0x522/0x7c0 kernel/events/core.c:10321 __perf_event_overflow+0x448/0x610 kernel/events/core.c:9496 perf_swevent_overflow kernel/events/core.c:9579 [inline] perf_swevent_event+0x315/0x570 kernel/events/core.c:9630 do_perf_sw_event kernel/events/core.c:9743 [inline] ___perf_sw_event+0x49e/0x6e0 kernel/events/core.c:9774 __perf_sw_event+0x135/0x260 kernel/events/core.c:9786 perf_sw_event include/linux/perf_event.h:1254 [inline] do_user_addr_fault+0xaea/0xb10 arch/x86/mm/fault.c:1284 handle_page_fault arch/x86/mm/fault.c:1429 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1482 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0010:do_strncpy_from_user lib/strncpy_from_user.c:41 [inline] RIP: 0010:strncpy_from_user+0x14b/0x350 lib/strncpy_from_user.c:139 Code: 4c 89 e6 e8 f7 dd 49 fd 49 83 fc 07 0f 86 a1 00 00 00 4c 89 74 24 08 48 c7 44 24 10 f8 ff ff ff 45 31 ed 4c 89 3c 24 48 89 dd <4f> 8b 3c 2f 48 b8 ff fe fe fe fe fe fe fe 49 8d 1c 07 4d 89 fe 49 RSP: 0018:ffffc90003837b50 EFLAGS: 00050246 RAX: ffffffff8438ac99 RBX: ffffc90003837c70 RCX: ffff888057b28000 RDX: 0000000000000002 RSI: 000000000000007f RDI: 0000000000000007 RBP: ffffc90003837c70 R08: ffff888057b28000 R09: 0000000000000003 R10: 0000000000000002 R11: 0000000000000002 R12: 000000000000007f R13: 0000000000000000 R14: 000000000000007f R15: 0000000000000000 strncpy_from_bpfptr include/linux/bpfptr.h:85 [inline] bpf_prog_load+0x1f3/0x1560 kernel/bpf/syscall.c:2535 __sys_bpf+0x5b8/0x780 kernel/bpf/syscall.c:5031 __do_sys_bpf kernel/bpf/syscall.c:5135 [inline] __se_sys_bpf kernel/bpf/syscall.c:5133 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5133 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: 0033:0x7f301899ce59 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:00007f3019868028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f3018c15fa0 RCX: 00007f301899ce59 RDX: 0000000000000094 RSI: 0000200000000600 RDI: 0000000000000005 RBP: 00007f3018a32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3018c16038 R14: 00007f3018c15fa0 R15: 00007ffea23f1a38 Allocated by task 31656: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc_node+0xb0/0x240 mm/slab_common.c:943 kmalloc_node include/linux/slab.h:589 [inline] __bpf_map_area_alloc kernel/bpf/syscall.c:328 [inline] bpf_map_area_alloc+0x47/0xe0 kernel/bpf/syscall.c:341 prealloc_elems_and_freelist+0x86/0x1c0 kernel/bpf/stackmap.c:51 stack_map_alloc+0x390/0x520 kernel/bpf/stackmap.c:117 find_and_alloc_map kernel/bpf/syscall.c:133 [inline] map_create+0x534/0x1000 kernel/bpf/syscall.c:1149 __sys_bpf+0x38b/0x780 kernel/bpf/syscall.c:5013 __do_sys_bpf kernel/bpf/syscall.c:5135 [inline] __se_sys_bpf kernel/bpf/syscall.c:5133 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5133 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 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486 call_rcu+0x14f/0x990 kernel/rcu/tree.c:2849 nf_nat_unregister_fn+0x1ea/0x370 net/netfilter/nf_nat_core.c:1097 ipt_nat_unregister_lookups net/ipv4/netfilter/iptable_nat.c:101 [inline] iptable_nat_net_pre_exit+0x50/0x90 net/ipv4/netfilter/iptable_nat.c:131 ops_pre_exit_list net/core/net_namespace.c:162 [inline] cleanup_net+0x591/0xba0 net/core/net_namespace.c:620 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff88807959c280 which belongs to the cache kmalloc-cg-64 of size 64 The buggy address is located 16 bytes inside of 64-byte region [ffff88807959c280, ffff88807959c2c0) The buggy address belongs to the physical page: page:ffffea0001e56700 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88807959cf00 pfn:0x7959c memcg:ffff888029a10a01 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0001e0a780 dead000000000007 ffff888017442780 raw: ffff88807959cf00 000000008020001a 00000001ffffffff ffff888029a10a01 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 4284, tgid 4284 (syz-executor), ts 107302215341, free_ts 107010073490 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559 prep_new_page mm/page_alloc.c:2566 [inline] get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5657 alloc_slab_page+0x5d/0x160 mm/slub.c:1799 allocate_slab mm/slub.c:1944 [inline] new_slab+0x87/0x2c0 mm/slub.c:1997 ___slab_alloc+0xbc6/0x1240 mm/slub.c:3154 __slab_alloc mm/slub.c:3240 [inline] slab_alloc_node mm/slub.c:3325 [inline] __kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc_node+0xa0/0x240 mm/slab_common.c:943 kmalloc_node include/linux/slab.h:589 [inline] kvmalloc_node+0x6c/0x180 mm/util.c:581 kvmalloc include/linux/slab.h:716 [inline] kvzalloc include/linux/slab.h:724 [inline] allocate_hook_entries_size net/netfilter/core.c:61 [inline] nf_hook_entries_grow+0x309/0x730 net/netfilter/core.c:128 __nf_register_net_hook+0x2c9/0x910 net/netfilter/core.c:423 nf_register_net_hook+0xae/0x190 net/netfilter/core.c:566 nf_register_net_hooks+0x40/0x1a0 net/netfilter/core.c:582 ebt_register_table+0xc97/0x1020 net/bridge/netfilter/ebtables.c:1274 find_inlist_lock_noload+0x178/0x260 net/bridge/netfilter/ebtables.c:343 find_inlist_lock net/bridge/netfilter/ebtables.c:370 [inline] find_table_lock net/bridge/netfilter/ebtables.c:379 [inline] do_ebt_get_ctl+0x2c7/0x1cf0 net/bridge/netfilter/ebtables.c:2468 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1486 [inline] free_pcp_prepare mm/page_alloc.c:1536 [inline] free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3508 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] slab_alloc mm/slub.c:3367 [inline] __kmem_cache_alloc_lru mm/slub.c:3374 [inline] kmem_cache_alloc_lru+0x11a/0x2e0 mm/slub.c:3390 alloc_inode_sb include/linux/fs.h:3245 [inline] shmem_alloc_inode+0x24/0x40 mm/shmem.c:3898 alloc_inode fs/inode.c:261 [inline] new_inode_pseudo+0x5f/0x1c0 fs/inode.c:1063 new_inode+0x25/0x1c0 fs/inode.c:1091 shmem_get_inode+0x347/0xbf0 mm/shmem.c:2354 shmem_mknod+0x55/0x1c0 mm/shmem.c:2935 shmem_mkdir+0x27/0x60 mm/shmem.c:2989 vfs_mkdir+0x387/0x570 fs/namei.c:4114 do_mkdirat+0x1d8/0x440 fs/namei.c:4139 __do_sys_mkdirat fs/namei.c:4154 [inline] __se_sys_mkdirat fs/namei.c:4152 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4152 Memory state around the buggy address: ffff88807959c180: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88807959c200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff88807959c280: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc ^ ffff88807959c300: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88807959c380: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== ---------------- Code disassembly (best guess): 0: 4c 89 e6 mov %r12,%rsi 3: e8 f7 dd 49 fd call 0xfd49ddff 8: 49 83 fc 07 cmp $0x7,%r12 c: 0f 86 a1 00 00 00 jbe 0xb3 12: 4c 89 74 24 08 mov %r14,0x8(%rsp) 17: 48 c7 44 24 10 f8 ff movq $0xfffffffffffffff8,0x10(%rsp) 1e: ff ff 20: 45 31 ed xor %r13d,%r13d 23: 4c 89 3c 24 mov %r15,(%rsp) 27: 48 89 dd mov %rbx,%rbp * 2a: 4f 8b 3c 2f mov (%r15,%r13,1),%r15 <-- trapping instruction 2e: 48 b8 ff fe fe fe fe movabs $0xfefefefefefefeff,%rax 35: fe fe fe 38: 49 8d 1c 07 lea (%r15,%rax,1),%rbx 3c: 4d 89 fe mov %r15,%r14 3f: 49 rex.WB