================================================================== BUG: KASAN: use-after-free in ax25_unregister_dev_sysctl+0x33/0xa0 net/ax25/sysctl_net_ax25.c:172 Read of size 8 at addr ffff88807a6a7818 by task syz.3.185/4941 CPU: 0 PID: 4941 Comm: syz.3.185 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x168/0x230 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_unregister_dev_sysctl+0x33/0xa0 net/ax25/sysctl_net_ax25.c:172 ax25_dev_device_down+0x5b/0x520 net/ax25/ax25_dev.c:101 ax25_device_event+0x4b4/0x4f0 net/ax25/af_ax25.c:144 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:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] dev_close_many+0x28d/0x400 net/core/dev.c:1650 dev_close+0x14c/0x200 net/core/dev.c:1672 bpq_device_event+0x2f4/0x9c0 drivers/net/hamradio/bpqether.c:548 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:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] dev_close_many+0x28d/0x400 net/core/dev.c:1650 dev_close+0x14c/0x200 net/core/dev.c:1672 bond_setup_by_slave+0x61/0x3a0 drivers/net/bonding/bond_main.c:1471 bond_enslave+0x77c/0x3a40 drivers/net/bonding/bond_main.c:1855 bond_do_ioctl+0x2a2/0x8c0 drivers/net/bonding/bond_main.c:4238 bond_siocdevprivate+0x13c/0x320 drivers/net/bonding/bond_main.c:-1 dev_siocdevprivate net/core/dev_ioctl.c:285 [inline] dev_ifsioc+0xaf5/0xe70 net/core/dev_ioctl.c:403 dev_ioctl+0x5f9/0xe50 net/core/dev_ioctl.c:612 sock_ioctl+0x67b/0x6e0 net/socket.c:1184 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 RIP: 0033:0x7fa88fc5afc9 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:00007fa88de80038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa88feb2180 RCX: 00007fa88fc5afc9 RDX: 0000200000000180 RSI: 00000000000089f0 RDI: 0000000000000008 RBP: 00007fa88fcddf91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa88feb2218 R14: 00007fa88feb2180 R15: 00007ffcc25d8e88 Allocated by task 4823: 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] call_usermodehelper_setup+0x8a/0x260 kernel/umh.c:365 call_modprobe kernel/kmod.c:93 [inline] __request_module+0x3be/0x910 kernel/kmod.c:170 dev_load+0x156/0x1b0 net/core/dev_ioctl.c:446 dev_ioctl+0x3e4/0xe50 net/core/dev_ioctl.c:511 sock_do_ioctl+0x222/0x2f0 net/socket.c:1154 sock_ioctl+0x4ed/0x6e0 net/socket.c:1257 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 4823: 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 call_usermodehelper_freeinfo kernel/umh.c:46 [inline] call_usermodehelper_exec+0x2b6/0x460 kernel/umh.c:454 call_modprobe kernel/kmod.c:98 [inline] __request_module+0x3df/0x910 kernel/kmod.c:170 dev_load+0x156/0x1b0 net/core/dev_ioctl.c:446 dev_ioctl+0x3e4/0xe50 net/core/dev_ioctl.c:511 sock_do_ioctl+0x222/0x2f0 net/socket.c:1154 sock_ioctl+0x4ed/0x6e0 net/socket.c:1257 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 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 insert_work+0x54/0x3d0 kernel/workqueue.c:1366 __queue_work+0x9c5/0xd50 kernel/workqueue.c:1532 queue_work_on+0x11d/0x1d0 kernel/workqueue.c:1559 queue_work include/linux/workqueue.h:512 [inline] call_usermodehelper_exec+0x26b/0x460 kernel/umh.c:435 call_modprobe kernel/kmod.c:98 [inline] __request_module+0x3df/0x910 kernel/kmod.c:170 dev_load+0x156/0x1b0 net/core/dev_ioctl.c:446 dev_ioctl+0x3e4/0xe50 net/core/dev_ioctl.c:511 sock_do_ioctl+0x222/0x2f0 net/socket.c:1154 sock_ioctl+0x4ed/0x6e0 net/socket.c:1257 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 The buggy address belongs to the object at ffff88807a6a7800 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 24 bytes inside of 192-byte region [ffff88807a6a7800, ffff88807a6a78c0) The buggy address belongs to the page: page:ffffea0001e9a9c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88807a6a7e00 pfn:0x7a6a7 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0000ac6dc8 ffffea0000a87ec8 ffff888016841a00 raw: ffff88807a6a7e00 000000000010000e 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 4363, ts 70063982646, free_ts 70053210340 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487 __alloc_pages_node include/linux/gfp.h:570 [inline] alloc_slab_page mm/slub.c:1782 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xb6/0x4b0 mm/slub.c:1980 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] __kmalloc_node+0x200/0x3b0 mm/slub.c:4456 kmalloc_array_node include/linux/slab.h:700 [inline] kcalloc_node include/linux/slab.h:705 [inline] memcg_alloc_page_obj_cgroups+0x81/0x120 mm/memcontrol.c:2839 memcg_slab_post_alloc_hook mm/slab.h:313 [inline] slab_post_alloc_hook+0xba/0x380 mm/slab.h:526 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x100/0x290 mm/slub.c:3238 __d_alloc+0x2a/0x6f0 fs/dcache.c:1749 d_alloc_pseudo+0x19/0x70 fs/dcache.c:1878 alloc_file_pseudo+0xc8/0x1f0 fs/file_table.c:256 sock_alloc_file+0xb3/0x240 net/socket.c:462 sock_map_fd net/socket.c:486 [inline] __sys_socket+0x11d/0x170 net/socket.c:1588 __do_sys_socket net/socket.c:1593 [inline] __se_sys_socket net/socket.c:1591 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1591 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 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page+0x94/0x280 mm/page_alloc.c:3396 __vunmap+0x8ab/0xa40 mm/vmalloc.c:2628 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Memory state around the buggy address: ffff88807a6a7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88807a6a7780: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc >ffff88807a6a7800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807a6a7880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88807a6a7900: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================