================================================================== BUG: KASAN: use-after-free in ax25_find_cb+0x175/0x3a0 net/ax25/af_ax25.c:232 Read of size 8 at addr ffff8881421c0a08 by task syz.7.2151/11802 CPU: 0 PID: 11802 Comm: syz.7.2151 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 ax25_find_cb+0x175/0x3a0 net/ax25/af_ax25.c:232 rose_link_up net/rose/rose_link.c:129 [inline] rose_transmit_link+0x169/0x730 net/rose/rose_link.c:271 rose_write_internal+0x680/0x1e90 net/rose/rose_subr.c:198 rose_release+0x22a/0x4e0 net/rose/af_rose.c:670 __sock_release net/socket.c:651 [inline] sock_close+0xd5/0x240 net/socket.c:1345 __fput+0x234/0x930 fs/file_table.c:311 task_work_run+0x125/0x1a0 kernel/task_work.c:188 get_signal+0x1222/0x12c0 kernel/signal.c:2672 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7faf54eef799 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:00007faf53149028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffe00 RBX: 00007faf55168fa0 RCX: 00007faf54eef799 RDX: 000000000000001c RSI: 0000200000000240 RDI: 000000000000000c RBP: 00007faf54f85c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007faf55169038 R14: 00007faf55168fa0 R15: 00007fff03fb9068 Allocated by task 11412: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522 kmalloc include/linux/slab.h:607 [inline] kzalloc include/linux/slab.h:738 [inline] ax25_dev_device_up+0x50/0x580 net/ax25/ax25_dev.c:55 ax25_device_event+0x483/0x4f0 net/ax25/af_ax25.c:139 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline] call_netdevice_notifiers net/core/dev.c:2088 [inline] __dev_notify_flags+0x194/0x300 net/core/dev.c:8917 dev_change_flags+0xe3/0x1a0 net/core/dev.c:8955 dev_ifsioc+0x130/0xd50 net/core/dev_ioctl.c:324 dev_ioctl+0x545/0xe30 net/core/dev_ioctl.c:572 sock_do_ioctl+0x245/0x320 net/socket.c:1161 sock_ioctl+0x4d2/0x710 net/socket.c:1266 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 11801: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xef/0x2a0 mm/slub.c:4564 ax25_dev_put include/net/ax25.h:302 [inline] ax25_release+0x661/0x870 net/ax25/af_ax25.c:1062 __sock_release net/socket.c:651 [inline] sock_close+0xd5/0x240 net/socket.c:1345 __fput+0x234/0x930 fs/file_table.c:311 task_work_run+0x125/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Last potentially related work creation: kasan_save_stack+0x35/0x60 mm/kasan/common.c:38 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348 kvfree_call_rcu+0x105/0x7d0 kernel/rcu/tree.c:3600 hash_netportnet6_add+0x2956/0x37b0 net/netfilter/ipset/ip_set_hash_gen.h:979 hash_netportnet6_uadt+0xb7f/0xf20 net/netfilter/ipset/ip_set_hash_netportnet.c:560 call_ad+0x182/0xa00 net/netfilter/ipset/ip_set_core.c:1753 ip_set_ad+0x816/0x9c0 net/netfilter/ipset/ip_set_core.c:1841 nfnetlink_rcv_msg+0xbb0/0x11f0 net/netfilter/nfnetlink.c:297 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507 nfnetlink_rcv+0x2b4/0x2460 net/netfilter/nfnetlink.c:654 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499 __sys_sendmsg net/socket.c:2528 [inline] __do_sys_sendmsg net/socket.c:2537 [inline] __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff8881421c0a00 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 8 bytes inside of 192-byte region [ffff8881421c0a00, ffff8881421c0ac0) The buggy address belongs to the page: page:ffffea0005087000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1421c0 flags: 0x57ff00000000200(slab|node=1|zone=2|lastcpupid=0x7ff) raw: 057ff00000000200 ffffea0000950800 0000000c0000000a ffff888016c41a00 raw: 0000000000000000 0000000000100010 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 3051480258, free_ts 0 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031 alloc_slab_page mm/slub.c:1780 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xc0/0x4b0 mm/slub.c:1980 ___slab_alloc+0x80a/0xdd0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc_trace+0x1a5/0x2a0 mm/slub.c:3250 kmalloc include/linux/slab.h:607 [inline] kzalloc include/linux/slab.h:738 [inline] call_usermodehelper_setup+0x8a/0x260 kernel/umh.c:365 kobject_uevent_env+0x65e/0x890 lib/kobject_uevent.c:629 kset_register+0x188/0x1f0 lib/kobject.c:894 bus_register+0x21c/0x6c0 drivers/base/bus.c:808 mmc_init+0xc/0x70 drivers/mmc/core/core.c:2323 do_one_initcall+0x272/0x730 init/main.c:1316 do_initcall_level+0x137/0x1f0 init/main.c:1389 do_initcalls+0x4b/0x90 init/main.c:1405 kernel_init_freeable+0x3e9/0x570 init/main.c:1629 kernel_init+0x19/0x1b0 init/main.c:1520 page_owner free stack trace missing Memory state around the buggy address: ffff8881421c0900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881421c0980: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881421c0a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881421c0a80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8881421c0b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================