================================================================== BUG: KASAN: use-after-free in ax25_release+0x5ca/0x870 net/ax25/af_ax25.c:1061 Read of size 8 at addr ffff8880799fe208 by task syz.3.83/4685 CPU: 1 PID: 4685 Comm: syz.3.83 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_release+0x5ca/0x870 net/ax25/af_ax25.c:1061 __sock_release net/socket.c:651 [inline] sock_close+0xd5/0x240 net/socket.c:1346 __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 RIP: 0033:0x7f7e64bcf6c9 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:00007ffc217bba58 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 000000000001a81b RCX: 00007f7e64bcf6c9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f7e64e27da0 R08: 0000000000000001 R09: 0000000b217bbd4f R10: 0000001b31420000 R11: 0000000000000246 R12: 00007f7e64e25fac R13: 00007f7e64e25fa0 R14: ffffffffffffffff R15: 00007ffc217bbb70 Allocated by task 4686: 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:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] __dev_notify_flags+0x178/0x2d0 net/core/dev.c:-1 dev_change_flags+0xe3/0x1a0 net/core/dev.c:8929 dev_ifsioc+0x147/0xe70 net/core/dev_ioctl.c:324 dev_ioctl+0x55f/0xe50 net/core/dev_ioctl.c:587 sock_do_ioctl+0x222/0x2f0 net/socket.c:1164 sock_ioctl+0x4ed/0x6e0 net/socket.c:1267 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 4686: 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_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_notify_flags+0x178/0x2d0 net/core/dev.c:-1 dev_change_flags+0xe3/0x1a0 net/core/dev.c:8929 dev_ifsioc+0x147/0xe70 net/core/dev_ioctl.c:324 dev_ioctl+0x55f/0xe50 net/core/dev_ioctl.c:587 sock_do_ioctl+0x222/0x2f0 net/socket.c:1164 sock_ioctl+0x4ed/0x6e0 net/socket.c:1267 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 crypto_probing_notify crypto/api.c:253 [inline] crypto_alg_mod_lookup+0x4c1/0x6d0 crypto/api.c:281 crypto_find_alg crypto/api.c:490 [inline] crypto_alloc_tfm_node+0x149/0x330 crypto/api.c:527 cryptd_alloc_aead+0xde/0x1f0 crypto/cryptd.c:1024 simd_aead_init+0x63/0x150 crypto/simd.c:370 crypto_create_tfm_node+0xfa/0x340 crypto/api.c:457 crypto_alloc_tfm_node+0x172/0x330 crypto/api.c:533 aead_bind+0x6d/0x120 crypto/algif_aead.c:477 alg_bind+0x2f1/0x550 crypto/af_alg.c:181 __sys_bind+0x2f4/0x3f0 net/socket.c:1730 __do_sys_bind net/socket.c:1741 [inline] __se_sys_bind net/socket.c:1739 [inline] __x64_sys_bind+0x76/0x80 net/socket.c:1739 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 ffff8880799fe200 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 8 bytes inside of 192-byte region [ffff8880799fe200, ffff8880799fe2c0) The buggy address belongs to the page: page:ffffea0001e67f80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x799fe flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0000855f40 0000000600000002 ffff888016841a00 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 4182, ts 80317989039, free_ts 80314833564 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_anon fs/dcache.c:1849 [inline] d_alloc_cursor+0x40/0xd0 fs/dcache.c:1855 dcache_dir_open+0x37/0x70 fs/libfs.c:82 do_dentry_open+0x7ff/0xf80 fs/open.c:826 do_open fs/namei.c:3616 [inline] path_openat+0x2682/0x2f30 fs/namei.c:3750 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777 do_sys_openat2+0x142/0x4a0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1280 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 tlb_batch_list_free mm/mmu_gather.c:61 [inline] tlb_finish_mmu+0x236/0x2e0 mm/mmu_gather.c:341 exit_mmap+0x3a6/0x5f0 mm/mmap.c:3218 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x5a1/0x20a0 kernel/exit.c:870 do_group_exit+0x12e/0x300 kernel/exit.c:997 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 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 Memory state around the buggy address: ffff8880799fe100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880799fe180: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc >ffff8880799fe200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880799fe280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880799fe300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================