================================================================== BUG: KASAN: use-after-free in ax25_fillin_cb_from_dev net/ax25/af_ax25.c:468 [inline] BUG: KASAN: use-after-free in ax25_fillin_cb+0x460/0x660 net/ax25/af_ax25.c:495 Read of size 4 at addr ffff88801e3e4638 by task syz.4.60/4430 CPU: 0 PID: 4430 Comm: syz.4.60 Not tainted 5.15.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 print_address_description+0x63/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0x16b/0x1c0 mm/kasan/report.c:451 ax25_fillin_cb_from_dev net/ax25/af_ax25.c:468 [inline] ax25_fillin_cb+0x460/0x660 net/ax25/af_ax25.c:495 ax25_setsockopt+0xab7/0xe70 net/ax25/af_ax25.c:690 __sys_setsockopt+0x57e/0x990 net/socket.c:2203 __do_sys_setsockopt net/socket.c:2214 [inline] __se_sys_setsockopt net/socket.c:2211 [inline] __x64_sys_setsockopt+0xb1/0xc0 net/socket.c:2211 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f64821b4169 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:00007f648001d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f64823ccfa0 RCX: 00007f64821b4169 RDX: 0000000000000019 RSI: 0000000000000101 RDI: 0000000000000007 RBP: 00007f6482235990 R08: 0000000000000010 R09: 0000000000000000 R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f64823ccfa0 R15: 00007fffc756f6a8 Allocated by task 4305: 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+0xba/0xf0 mm/kasan/common.c:513 kasan_kmalloc include/linux/kasan.h:264 [inline] kmem_cache_alloc_trace+0x143/0x290 mm/slub.c:3247 kmalloc include/linux/slab.h:604 [inline] kzalloc include/linux/slab.h:735 [inline] ax25_dev_device_up+0x51/0x5a0 net/ax25/ax25_dev.c:55 ax25_device_event+0x4a0/0x510 net/ax25/af_ax25.c:139 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:391 __dev_notify_flags+0x1fd/0x3f0 net/core/dev.c:-1 dev_change_flags+0xe7/0x190 net/core/dev.c:8928 dev_ifsioc+0x147/0x10c0 net/core/dev_ioctl.c:324 dev_ioctl+0x504/0xf60 net/core/dev_ioctl.c:587 sock_do_ioctl+0x34f/0x5a0 net/socket.c:1154 sock_ioctl+0x484/0x770 net/socket.c:1257 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 4379: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x80 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kfree+0xf1/0x270 mm/slub.c:4559 ax25_dev_put include/net/ax25.h:302 [inline] ax25_release+0x3b3/0x840 net/ax25/af_ax25.c:1062 __sock_release net/socket.c:649 [inline] sock_close+0xcd/0x230 net/socket.c:1336 __fput+0x3fe/0x8e0 fs/file_table.c:311 task_work_run+0x129/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff88801e3e4600 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 56 bytes inside of 192-byte region [ffff88801e3e4600, ffff88801e3e46c0) The buggy address belongs to the page: page:ffffea000078f900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1e3e4 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888017441a00 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 4305, ts 70236393980, free_ts 70233315770 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x3b78/0x3d40 mm/page_alloc.c:4192 __alloc_pages+0x272/0x700 mm/page_alloc.c:5466 __alloc_pages_node include/linux/gfp.h:570 [inline] alloc_slab_page mm/slub.c:1777 [inline] allocate_slab mm/slub.c:1912 [inline] new_slab+0xb1/0x4b0 mm/slub.c:1975 ___slab_alloc+0x6f6/0xe10 mm/slub.c:3008 __slab_alloc mm/slub.c:3095 [inline] slab_alloc_node mm/slub.c:3186 [inline] __kmalloc_node+0x1fa/0x390 mm/slub.c:4451 kmalloc_array_node include/linux/slab.h:697 [inline] kcalloc_node include/linux/slab.h:702 [inline] memcg_alloc_page_obj_cgroups+0x7e/0x120 mm/memcontrol.c:2841 memcg_slab_post_alloc_hook mm/slab.h:313 [inline] slab_post_alloc_hook+0xb6/0x380 mm/slab.h:526 slab_alloc_node mm/slub.c:3220 [inline] slab_alloc mm/slub.c:3228 [inline] kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233 __d_alloc+0x2a/0x700 fs/dcache.c:1749 d_alloc_pseudo+0x19/0x70 fs/dcache.c:1878 alloc_file_pseudo+0x131/0x2f0 fs/file_table.c:256 sock_alloc_file+0xb4/0x240 net/socket.c:462 sock_map_fd net/socket.c:486 [inline] __sys_socket+0x194/0x370 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+0x3b/0xb0 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+0xc34/0xcf0 mm/page_alloc.c:3317 free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396 free_slab mm/slub.c:2015 [inline] discard_slab mm/slub.c:2021 [inline] __unfreeze_partials+0x1b7/0x210 mm/slub.c:2507 put_cpu_partial+0x132/0x1a0 mm/slub.c:2587 do_slab_free mm/slub.c:3487 [inline] ___cache_free+0xe3/0x100 mm/slub.c:3506 qlist_free_all+0x36/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x162/0x180 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xc0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x53/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3220 [inline] slab_alloc mm/slub.c:3228 [inline] kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233 getname_flags+0xb8/0x4e0 fs/namei.c:138 user_path_at_empty+0x2a/0x180 fs/namei.c:2882 user_path_at include/linux/namei.h:57 [inline] vfs_statx+0x106/0x3b0 fs/stat.c:221 vfs_fstatat fs/stat.c:243 [inline] __do_sys_newfstatat fs/stat.c:411 [inline] __se_sys_newfstatat fs/stat.c:405 [inline] __x64_sys_newfstatat+0x12c/0x1b0 fs/stat.c:405 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Memory state around the buggy address: ffff88801e3e4500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88801e3e4580: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc >ffff88801e3e4600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801e3e4680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88801e3e4700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================