================================================================== BUG: KASAN: slab-out-of-bounds in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: slab-out-of-bounds in fbcon_prepare_logo+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:613 Read of size 10 at addr ffff88802639a99a by task syz.2.3936/19912 CPU: 1 UID: 0 PID: 19912 Comm: syz.2.3936 Not tainted 6.15.0-rc4-syzkaller-00256-g95d3481af6dc #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 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:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189 __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:613 fbcon_init+0xd77/0x1900 drivers/video/fbdev/core/fbcon.c:1145 visual_init+0x31d/0x620 drivers/tty/vt/vt.c:1011 do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3831 vt_bind drivers/tty/vt/vt.c:3987 [inline] store_bind+0x61d/0x760 drivers/tty/vt/vt.c:4059 dev_attr_store+0x55/0x80 drivers/base/core.c:2440 sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x351/0x510 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x5ba/0x1180 fs/read_write.c:684 ksys_write+0x12a/0x240 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f935ef8e969 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:00007f935fdfb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f935f1b6080 RCX: 00007f935ef8e969 RDX: 00000000fffffdef RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f935f010ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f935f1b6080 R15: 00007ffdde2f8d58 Allocated by task 19895: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] ref_tracker_alloc+0x18e/0x5b0 lib/ref_tracker.c:203 __netns_tracker_alloc include/net/net_namespace.h:357 [inline] sk_alloc+0xaf4/0xc20 net/core/sock.c:2270 tipc_sk_create+0xcf/0x21a0 net/tipc/socket.c:486 __sock_create+0x335/0x8d0 net/socket.c:1541 tipc_topsrv_create_listener net/tipc/topsrv.c:518 [inline] tipc_topsrv_start net/tipc/topsrv.c:683 [inline] tipc_topsrv_init_net+0x4f8/0x9e0 net/tipc/topsrv.c:725 ops_init+0x1df/0x5f0 net/core/net_namespace.c:138 setup_net+0x21e/0x850 net/core/net_namespace.c:364 copy_net_ns+0x2a6/0x5f0 net/core/net_namespace.c:518 create_new_namespaces+0x3ea/0xad0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:228 ksys_unshare+0x45b/0xa40 kernel/fork.c:3375 __do_sys_unshare kernel/fork.c:3446 [inline] __se_sys_unshare kernel/fork.c:3444 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3444 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802639a980 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 26 bytes inside of allocated 32-byte region [ffff88802639a980, ffff88802639a9a0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2639a anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801b441780 0000000000000000 dead000000000001 raw: 0000000000000000 0000000080400040 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5826, tgid 5826 (syz-executor), ts 96524640422, free_ts 96523467418 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718 prep_new_page mm/page_alloc.c:1726 [inline] get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2450 [inline] allocate_slab mm/slub.c:2618 [inline] new_slab+0x244/0x340 mm/slub.c:2672 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948 __slab_alloc_node mm/slub.c:4023 [inline] slab_alloc_node mm/slub.c:4184 [inline] __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] ref_tracker_alloc+0x18e/0x5b0 lib/ref_tracker.c:203 __netdev_tracker_alloc include/linux/netdevice.h:4331 [inline] netdev_hold include/linux/netdevice.h:4360 [inline] netdev_hold include/linux/netdevice.h:4355 [inline] qdisc_alloc+0x900/0xc50 net/sched/sch_generic.c:986 qdisc_create_dflt+0x73/0x430 net/sched/sch_generic.c:1009 attach_one_default_qdisc net/sched/sch_generic.c:1175 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2650 [inline] attach_default_qdiscs net/sched/sch_generic.c:1193 [inline] dev_activate+0x63f/0x12d0 net/sched/sch_generic.c:1252 __dev_open+0x43a/0x7d0 net/core/dev.c:1638 __dev_change_flags+0x55d/0x720 net/core/dev.c:9366 netif_change_flags+0x8d/0x160 net/core/dev.c:9429 do_setlink.constprop.0+0xddf/0x44b0 net/core/rtnetlink.c:3152 page last free pid 5869 tgid 5869 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725 vfree+0x176/0x960 mm/vmalloc.c:3383 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:3303 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88802639a880: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc ffff88802639a900: fa fb fb fb fc fc fc fc 00 00 04 fc fc fc fc fc >ffff88802639a980: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc ^ ffff88802639aa00: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc ffff88802639aa80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc ==================================================================