================================================================== 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+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:646 Read of size 256 at addr ffff8880801de3c0 by task syz.2.2220/15413 CPU: 0 UID: 0 PID: 15413 Comm: syz.2.2220 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:194 [inline] kasan_check_range+0x100/0x1b0 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+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:646 fbcon_init+0xda0/0x1930 drivers/video/fbdev/core/fbcon.c:1179 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1020 do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3960 vt_bind drivers/tty/vt/vt.c:4116 [inline] store_bind+0x61d/0x760 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+0x3af/0x570 fs/kernfs/file.c:352 iter_file_splice_write+0xa24/0x12b0 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+0xb06/0xe50 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+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fce03b8f7c9 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:00007fce04a62038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fce03de6090 RCX: 00007fce03b8f7c9 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000004 RBP: 00007fce03c13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fce03de6128 R14: 00007fce03de6090 R15: 00007ffcd58e2ff8 Allocated by task 14560: kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kmalloc_noprof include/linux/slab.h:957 [inline] slab_free_hook mm/slub.c:2492 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x147/0x770 mm/slub.c:6781 mempool_free+0xde/0x130 mm/mempool.c:712 bio_put_percpu_cache block/bio.c:808 [inline] bio_put+0x355/0x5b0 block/bio.c:827 bio_endio+0x751/0x8a0 block/bio.c:1675 blk_update_request+0x914/0x15c0 block/blk-mq.c:1007 scsi_end_request+0x7c/0x9b0 drivers/scsi/scsi_lib.c:638 scsi_io_completion+0x17d/0x1490 drivers/scsi/scsi_lib.c:1079 scsi_complete+0x3fc/0x580 drivers/scsi/scsi_lib.c:1559 blk_complete_reqs+0xb1/0xf0 block/blk-mq.c:1244 handle_softirqs+0x219/0x950 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 common_interrupt+0xbf/0xe0 arch/x86/kernel/irq.c:319 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688 Freed by task 15103: kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x60 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:6670 [inline] kfree+0x2f8/0x6e0 mm/slub.c:6878 slab_free_after_rcu_debug+0x5d/0x300 mm/slub.c:6716 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0x79c/0x15f0 kernel/rcu/tree.c:2857 handle_softirqs+0x219/0x950 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:510 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] ip6t_do_table+0xc02/0x1c30 net/ipv6/netfilter/ip6_tables.c:375 ip6t_mangle_out net/ipv6/netfilter/ip6table_mangle.c:49 [inline] ip6table_mangle_hook+0x31e/0x770 net/ipv6/netfilter/ip6table_mangle.c:72 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbe/0x200 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] __ip6_local_out+0x428/0xa80 net/ipv6/output_core.c:145 ip6_local_out+0x2e/0x4d0 net/ipv6/output_core.c:155 ip6_send_skb+0x112/0x460 net/ipv6/ip6_output.c:1994 udp_v6_send_skb+0x96f/0x1910 net/ipv6/udp.c:1441 udpv6_sendmsg+0x23b1/0x2d30 net/ipv6/udp.c:1732 inet6_sendmsg+0x105/0x140 net/ipv6/af_inet6.c:659 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x705/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmmsg+0x200/0x420 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+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Last potentially related work creation: kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556 __call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3119 slab_free_hook mm/slub.c:2504 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x171/0x770 mm/slub.c:6781 mempool_free+0xde/0x130 mm/mempool.c:712 bio_put_percpu_cache block/bio.c:808 [inline] bio_put+0x355/0x5b0 block/bio.c:827 bio_endio+0x751/0x8a0 block/bio.c:1675 blk_update_request+0x914/0x15c0 block/blk-mq.c:1007 scsi_end_request+0x7c/0x9b0 drivers/scsi/scsi_lib.c:638 scsi_io_completion+0x17d/0x1490 drivers/scsi/scsi_lib.c:1079 scsi_complete+0x3fc/0x580 drivers/scsi/scsi_lib.c:1559 blk_complete_reqs+0xb1/0xf0 block/blk-mq.c:1244 handle_softirqs+0x219/0x950 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 common_interrupt+0xbf/0xe0 arch/x86/kernel/irq.c:319 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688 The buggy address belongs to the object at ffff8880801de3c0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 0 bytes inside of freed 32-byte region [ffff8880801de3c0, ffff8880801de3e0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880801de4c0 pfn:0x801de flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000200 ffff88813ff26780 ffffea0000bb3a10 ffffea000202cb90 raw: ffff8880801de4c0 0000000000400037 00000000f5000000 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 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 12425, tgid 12424 (syz.0.1448), ts 480291366371, free_ts 467116281566 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210 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+0x2c3/0x430 mm/slub.c:3302 ___slab_alloc+0xe18/0x1c90 mm/slub.c:4656 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __kmalloc_cache_noprof+0x485/0x800 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] slab_free_hook mm/slub.c:2492 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x147/0x770 mm/slub.c:6781 anon_vma_free mm/rmap.c:136 [inline] __put_anon_vma+0x114/0x3a0 mm/rmap.c:2780 put_anon_vma include/linux/rmap.h:117 [inline] unlink_anon_vmas+0x58a/0x820 mm/rmap.c:443 free_pgtables+0x212/0xc10 mm/memory.c:414 exit_mmap+0x3f1/0xb60 mm/mmap.c:1288 __mmput+0x12a/0x410 kernel/fork.c:1173 mmput+0x62/0x70 kernel/fork.c:1196 exit_mm kernel/exit.c:581 [inline] do_exit+0x7d7/0x2bd0 kernel/exit.c:959 page last free pid 5996 tgid 5996 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943 kasan_depopulate_vmalloc_pte+0x5b/0x80 mm/kasan/shadow.c:484 apply_to_pte_range mm/memory.c:3182 [inline] apply_to_pmd_range mm/memory.c:3226 [inline] apply_to_pud_range mm/memory.c:3262 [inline] apply_to_p4d_range mm/memory.c:3298 [inline] __apply_to_page_range+0xac1/0x13f0 mm/memory.c:3334 __kasan_release_vmalloc+0xd1/0xe0 mm/kasan/shadow.c:602 kasan_release_vmalloc include/linux/kasan.h:593 [inline] kasan_release_vmalloc_node mm/vmalloc.c:2282 [inline] purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299 __purge_vmap_area_lazy+0x9d2/0xc00 mm/vmalloc.c:2389 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2423 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: ffff8880801de280: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ffff8880801de300: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc >ffff8880801de380: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ^ ffff8880801de400: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ffff8880801de480: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ==================================================================