================================================================== 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+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:686 Read of size 26 at addr ffff8880a37bb4ea by task syz.5.1641/13455 CPU: 0 UID: 0 PID: 13455 Comm: syz.5.1641 Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1d0 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+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:686 fbcon_init+0x1065/0x1830 drivers/video/fbdev/core/fbcon.c:1228 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1048 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:4056 vt_bind drivers/tty/vt/vt.c:4212 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4284 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 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f989459cdd9 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:00007f98954fe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f9894816180 RCX: 00007f989459cdd9 RDX: 000000000008083a RSI: 00002000000000c0 RDI: 0000000000000002 RBP: 00007f9894632d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9894816218 R14: 00007f9894816180 R15: 00007ffe63b44048 Allocated by task 13459: kasan_save_stack+0x30/0x50 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 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5295 [inline] __kmalloc_node_track_caller_noprof+0x304/0x850 mm/slub.c:5407 kmemdup_noprof+0x29/0x60 mm/util.c:138 kmemdup_noprof include/linux/fortify-string.h:763 [inline] neigh_parms_alloc+0x85/0x5e0 net/core/neighbour.c:1772 inetdev_init+0x13c/0x570 net/ipv4/devinet.c:280 inetdev_event+0x7fa/0x17f0 net/ipv4/devinet.c:1590 notifier_call_chain+0x99/0x400 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2249 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] register_netdevice+0x18fe/0x24b0 net/core/dev.c:11458 __ip_tunnel_create+0x52b/0x670 net/ipv4/ip_tunnel.c:268 ip_tunnel_init_net+0x230/0x780 net/ipv4/ip_tunnel.c:1147 ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137 setup_net+0x118/0x3a0 net/core/net_namespace.c:446 copy_net_ns+0x46f/0x7c0 net/core/net_namespace.c:579 create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:132 unshare_nsproxy_namespaces+0xf2/0x220 kernel/nsproxy.c:234 ksys_unshare+0x438/0xab0 kernel/fork.c:3243 __do_sys_unshare kernel/fork.c:3317 [inline] __se_sys_unshare kernel/fork.c:3315 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3315 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880a37bb400 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 74 bytes to the right of allocated 160-byte region [ffff8880a37bb400, ffff8880a37bb4a0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa37bb flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813fe2e3c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 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 0xd2c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 8326, tgid 8325 (syz.2.590), ts 248666612765, free_ts 248520831829 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab mm/slub.c:3467 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3525 refill_objects+0x277/0x420 mm/slub.c:7255 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] __do_kmalloc_node mm/slub.c:5294 [inline] __kmalloc_noprof+0x688/0x850 mm/slub.c:5307 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] ext4_find_extent+0x21b/0xa30 fs/ext4/extents.c:918 ext4_ext_map_blocks+0x20a/0x5930 fs/ext4/extents.c:4286 ext4_map_create_blocks+0xec/0x5e0 fs/ext4/inode.c:631 ext4_map_blocks+0x46b/0xd30 fs/ext4/inode.c:824 mpage_map_one_extent fs/ext4/inode.c:2396 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2490 [inline] ext4_do_writepages+0x2313/0x3f20 fs/ext4/inode.c:2948 ext4_writepages+0x347/0x790 fs/ext4/inode.c:3042 do_writepages+0x278/0x600 mm/page-writeback.c:2571 filemap_writeback+0x22d/0x2e0 mm/filemap.c:388 filemap_fdatawrite_range mm/filemap.c:413 [inline] file_write_and_wait_range+0xcd/0x140 mm/filemap.c:787 page last free pid 8312 tgid 8308 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0x747/0x1040 mm/page_alloc.c:2943 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869 handle_softirqs+0x1ea/0xa00 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 Memory state around the buggy address: ffff8880a37bb380: 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a37bb400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880a37bb480: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880a37bb500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a37bb580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================