================================================================== BUG: KASAN: slab-use-after-free in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: slab-use-after-free in fbcon_prepare_logo+0x945/0xc50 drivers/video/fbdev/core/fbcon.c:646 Read of size 256 at addr ffff888032dee3c0 by task syz.2.1790/13213 CPU: 0 UID: 0 PID: 13213 Comm: syz.2.1790 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1a0 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105 scr_memcpyw include/linux/vt_buffer.h:38 [inline] fbcon_prepare_logo+0x945/0xc50 drivers/video/fbdev/core/fbcon.c:646 fbcon_init+0x10ee/0x1810 drivers/video/fbdev/core/fbcon.c:1179 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1020 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3960 vt_bind drivers/tty/vt/vt.c:4116 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4188 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 iter_file_splice_write+0x82b/0x10a0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1161 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1230 do_sendfile+0xadc/0xe20 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64 fs/read_write.c:1417 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5bdc59aeb9 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:00007f5bdd408028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f5bdc816360 RCX: 00007f5bdc59aeb9 RDX: 0000000000000000 RSI: 000000000000000d RDI: 0000000000000006 RBP: 00007f5bdc608c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5bdc8163f8 R14: 00007f5bdc816360 R15: 00007ffe33fb20f8 Allocated by task 13052: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x303/0x880 mm/slub.c:5315 kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:586 __alloc_skb+0x186/0x410 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] __ip6_append_data+0x3699/0x4de0 net/ipv6/ip6_output.c:1681 ip6_append_data+0x1bb/0x4d0 net/ipv6/ip6_output.c:1870 rawv6_sendmsg+0x1773/0x48e0 net/ipv6/raw.c:912 inet_sendmsg+0x11c/0x140 net/ipv4/af_inet.c:859 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x9ad/0xc30 net/socket.c:2592 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2646 __sys_sendmmsg+0x205/0x430 net/socket.c:2735 __do_sys_sendmmsg net/socket.c:2762 [inline] __se_sys_sendmmsg net/socket.c:2759 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2759 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6674 [inline] kmem_cache_free+0x143/0x720 mm/slub.c:6785 skb_kfree_head net/core/skbuff.c:1066 [inline] skb_kfree_head net/core/skbuff.c:1063 [inline] skb_free_head+0x1c6/0x220 net/core/skbuff.c:1080 skb_release_data+0x540/0x700 net/core/skbuff.c:1107 skb_release_all net/core/skbuff.c:1182 [inline] __kfree_skb net/core/skbuff.c:1196 [inline] sk_skb_reason_drop+0x102/0x1b0 net/core/skbuff.c:1234 kfree_skb_reason include/linux/skbuff.h:1322 [inline] __skb_queue_purge_reason include/linux/skbuff.h:3425 [inline] __skb_queue_purge include/linux/skbuff.h:3430 [inline] inet_sock_destruct+0x117/0x800 net/ipv4/af_inet.c:139 __sk_destruct+0x85/0xbb0 net/core/sock.c:2350 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0x7c0/0x15c0 kernel/rcu/tree.c:2857 handle_softirqs+0x1ea/0x910 kernel/softirq.c:622 run_ksoftirqd kernel/softirq.c:1063 [inline] run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 The buggy address belongs to the object at ffff888032dee3c0 which belongs to the cache skbuff_small_head of size 704 The buggy address is located 0 bytes inside of freed 704-byte region [ffff888032dee3c0, ffff888032dee680) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x32dec head: order:2 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 ffff88801eac9b40 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000130013 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801eac9b40 dead000000000100 dead000000000122 head: 0000000000000000 0000000000130013 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea0000cb7b01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 12386, tgid 12384 (syz.3.1642), ts 463308951883, free_ts 463279555815 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1e1/0x250 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0xe3d/0x2e10 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5240 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0x2c4/0x440 mm/slub.c:3302 ___slab_alloc+0xda3/0x1ca0 mm/slub.c:4656 __slab_alloc.isra.0+0x63/0x110 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] kmem_cache_alloc_node_noprof+0x51e/0x880 mm/slub.c:5315 kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:586 __alloc_skb+0x186/0x410 net/core/skbuff.c:690 skb_copy+0x1ca/0x3a0 net/core/skbuff.c:2163 mac80211_hwsim_tx_frame_no_nl.isra.0+0xbf6/0x1370 drivers/net/wireless/virtual/mac80211_hwsim.c:1891 mac80211_hwsim_tx_frame+0x1f6/0x2a0 drivers/net/wireless/virtual/mac80211_hwsim.c:2264 __mac80211_hwsim_beacon_tx drivers/net/wireless/virtual/mac80211_hwsim.c:2281 [inline] mac80211_hwsim_beacon_tx+0x57e/0xa00 drivers/net/wireless/virtual/mac80211_hwsim.c:2365 __iterate_interfaces+0x2e6/0x650 net/mac80211/util.c:761 ieee80211_iterate_active_interfaces_atomic+0x71/0x1b0 net/mac80211/util.c:797 page last free pid 11080 tgid 11080 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x822/0x1130 mm/page_alloc.c:2973 ops_free_list net/core/net_namespace.c:215 [inline] ops_undo_list+0x4c2/0xab0 net/core/net_namespace.c:256 cleanup_net+0x419/0x830 net/core/net_namespace.c:696 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3421 kthread+0x3b3/0x730 kernel/kthread.c:463 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Memory state around the buggy address: ffff888032dee280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888032dee300: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff888032dee380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ^ ffff888032dee400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888032dee480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================