================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline] BUG: KASAN: slab-use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline] BUG: KASAN: slab-use-after-free in __refcount_add include/linux/refcount.h:283 [inline] BUG: KASAN: slab-use-after-free in __refcount_inc include/linux/refcount.h:366 [inline] BUG: KASAN: slab-use-after-free in refcount_inc include/linux/refcount.h:383 [inline] BUG: KASAN: slab-use-after-free in kref_get include/linux/kref.h:45 [inline] BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90 fs/configfs/item.c:104 Write of size 4 at addr ffff8880330dd01c by task syz.4.512/7656 CPU: 0 UID: 0 PID: 7656 Comm: syz.4.512 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read_write include/linux/instrumented.h:112 [inline] atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline] __refcount_add include/linux/refcount.h:283 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] kref_get include/linux/kref.h:45 [inline] config_item_get+0x26/0x90 fs/configfs/item.c:104 configfs_get_config_item fs/configfs/configfs_internal.h:127 [inline] get_target fs/configfs/symlink.c:128 [inline] configfs_symlink+0x4b8/0x13c0 fs/configfs/symlink.c:185 vfs_symlink+0x18b/0x330 fs/namei.c:5660 filename_symlinkat+0x1cd/0x410 fs/namei.c:5685 __do_sys_symlinkat fs/namei.c:5705 [inline] __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5700 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10a/0x4d0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f102499de99 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:00007f102583a028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00007f1024c25fa0 RCX: 00007f102499de99 RDX: 0000200000000340 RSI: ffffffffffffff9c RDI: 0000200000000300 RBP: 00007f1024a33eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1024c26038 R14: 00007f1024c25fa0 R15: 00007ffdd65bd148 Allocated by task 7656: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x72/0x90 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x620 mm/slub.c:5489 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] afunc_alloc_inst+0x4c/0x770 drivers/usb/gadget/function/f_uac2.c:2192 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe3/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x127/0x360 drivers/usb/gadget/configfs.c:626 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x406/0x620 fs/namei.c:5276 filename_mkdirat+0x285/0x510 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10a/0x4d0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e The buggy address belongs to the object at ffff8880330dd000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 28 bytes inside of freed 2048-byte region [ffff8880330dd000, ffff8880330dd800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x330d8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813ff04000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ff04000 dead000000000100 dead000000000122 head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 23, tgid 23 (kworker/1:0), ts 88209991329, free_ts 82370997738 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x21df/0x2250 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab+0x79/0x5d0 mm/slub.c:3380 new_slab mm/slub.c:3426 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x2bf/0x690 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_node_track_caller_noprof+0x53a/0x720 mm/slub.c:5471 kmalloc_reserve net/core/skbuff.c:637 [inline] __alloc_skb+0x2bd/0x740 net/core/skbuff.c:715 alloc_skb include/linux/skbuff.h:1384 [inline] mld_newpack+0x12a/0xbc0 net/ipv6/mcast.c:1789 add_grhead net/ipv6/mcast.c:1900 [inline] add_grec+0x1364/0x1840 net/ipv6/mcast.c:2039 mld_send_cr net/ipv6/mcast.c:2164 [inline] mld_ifc_work+0x6f1/0xd60 net/ipv6/mcast.c:2710 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa39/0x1400 kernel/workqueue.c:3405 worker_thread+0xa4d/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x510/0xb60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page last free pid 5529 tgid 5520 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xbc1/0xc90 mm/page_alloc.c:2950 __folio_put+0x2b5/0x350 mm/swap.c:112 folio_put include/linux/mm.h:2124 [inline] put_page include/linux/mm.h:2193 [inline] put_netmem include/net/netmem.h:394 [inline] skb_page_unref include/linux/skbuff_ref.h:43 [inline] __skb_frag_unref include/linux/skbuff_ref.h:56 [inline] skb_release_data+0x573/0xab0 net/core/skbuff.c:1116 skb_release_all net/core/skbuff.c:1197 [inline] __kfree_skb net/core/skbuff.c:1211 [inline] napi_consume_skb+0x193/0x2a0 net/core/skbuff.c:1542 skb_defer_free_flush+0x191/0x260 net/core/dev.c:6868 net_rx_action+0x465/0xd30 net/core/dev.c:7936 handle_softirqs+0x225/0x830 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf6/0x130 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:914 [inline] __dev_queue_xmit+0x17dd/0x2ed0 net/core/dev.c:4913 dev_queue_xmit include/linux/netdevice.h:3446 [inline] neigh_hh_output include/net/neighbour.h:544 [inline] neigh_output include/net/neighbour.h:558 [inline] ip_finish_output2+0xb6e/0xfe0 net/ipv4/ip_output.c:236 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x440 net/ipv4/ip_output.c:437 __ip_queue_xmit+0x105c/0x1b10 net/ipv4/ip_output.c:533 __tcp_transmit_skb+0x2be7/0x4650 net/ipv4/tcp_output.c:1717 tcp_cleanup_rbuf net/ipv4/tcp.c:1611 [inline] tcp_recvmsg_locked+0x2ec5/0x3800 net/ipv4/tcp.c:2915 tcp_recvmsg+0x203/0x7f0 net/ipv4/tcp.c:2944 Memory state around the buggy address: ffff8880330dcf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880330dcf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880330dd000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880330dd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880330dd100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================