================================================================== 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:646 Read of size 256 at addr ffff88807df49860 by task syz.3.2279/16431 CPU: 0 UID: 0 PID: 16431 Comm: syz.3.2279 Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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/0x1e0 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:646 fbcon_init+0x10a0/0x1820 drivers/video/fbdev/core/fbcon.c:1180 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1014 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3954 vt_bind drivers/tty/vt/vt.c:4110 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4182 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+0x830/0x10a0 fs/splice.c:736 do_splice_from fs/splice.c:936 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1159 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1103 do_splice_direct_actor fs/splice.c:1202 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1228 do_sendfile+0xadc/0xe20 fs/read_write.c:1372 __do_sys_sendfile64 fs/read_write.c:1433 [inline] __se_sys_sendfile64 fs/read_write.c:1419 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1419 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f409759c799 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:00007f4098475028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f4097816180 RCX: 00007f409759c799 RDX: 0000000000000000 RSI: 000000000000000b RDI: 0000000000000006 RBP: 00007f4097632bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4097816218 R14: 00007f4097816180 R15: 00007ffeee177cf8 Allocated by task 16425: 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:5263 [inline] __kmalloc_noprof+0x301/0x850 mm/slub.c:5275 kmalloc_noprof include/linux/slab.h:954 [inline] sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2245 sk_alloc+0x36/0xe80 net/core/sock.c:2301 __netlink_create+0x5e/0x2c0 net/netlink/af_netlink.c:626 __netlink_kernel_create+0xed/0x750 net/netlink/af_netlink.c:2018 netlink_kernel_create include/linux/netlink.h:62 [inline] diag_net_init+0xbd/0x140 net/core/sock_diag.c:334 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:581 create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:130 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x473/0xad0 kernel/fork.c:3174 __do_sys_unshare kernel/fork.c:3245 [inline] __se_sys_unshare kernel/fork.c:3243 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807df49000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 264 bytes to the right of allocated 1880-byte region [ffff88807df49000, ffff88807df49758) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7df48 head: order:3 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 ffff88813fe3d000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fe3d000 dead000000000100 dead000000000122 head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0001f7d201 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5825, tgid 5825 (syz-executor), ts 72597385815, free_ts 70651409437 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3296 [inline] allocate_slab mm/slub.c:3485 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3543 refill_objects+0x26b/0x400 mm/slub.c:7178 refill_sheaf mm/slub.c:2818 [inline] alloc_full_sheaf mm/slub.c:2839 [inline] __pcs_replace_empty_main+0x1ab/0x600 mm/slub.c:4629 alloc_from_pcs mm/slub.c:4720 [inline] slab_alloc_node mm/slub.c:4854 [inline] __do_kmalloc_node mm/slub.c:5262 [inline] __kmalloc_node_track_caller_noprof+0x694/0x850 mm/slub.c:5371 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:635 pskb_expand_head+0x246/0xfe0 net/core/skbuff.c:2315 netlink_trim+0x22d/0x2f0 net/netlink/af_netlink.c:1299 netlink_broadcast_filtered+0xd7/0xf50 net/netlink/af_netlink.c:1512 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xb1/0x290 net/netlink/af_netlink.c:2593 rtnl_notify net/core/rtnetlink.c:958 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:4436 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4452 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4439 [inline] rtmsg_ifinfo+0x177/0x1b0 net/core/rtnetlink.c:4458 __dev_notify_flags+0x24c/0x2e0 net/core/dev.c:9799 netif_change_flags+0x108/0x160 net/core/dev.c:9832 do_setlink.isra.0+0x1abb/0x3e50 net/core/rtnetlink.c:3158 page last free pid 5811 tgid 5811 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978 __folio_put+0x3b4/0x540 mm/swap.c:112 folio_put include/linux/mm.h:1817 [inline] put_page include/linux/mm.h:1886 [inline] put_netmem include/net/netmem.h:420 [inline] skb_page_unref include/linux/skbuff_ref.h:43 [inline] __skb_frag_unref include/linux/skbuff_ref.h:56 [inline] skb_release_data+0x667/0x9d0 net/core/skbuff.c:1122 skb_release_all net/core/skbuff.c:1203 [inline] __kfree_skb+0x4f/0x70 net/core/skbuff.c:1217 tcp_wmem_free_skb include/net/tcp.h:336 [inline] tcp_rtx_queue_unlink_and_free include/net/tcp.h:2269 [inline] tcp_clean_rtx_queue net/ipv4/tcp_input.c:3698 [inline] tcp_ack+0x2072/0x74f0 net/ipv4/tcp_input.c:4366 tcp_rcv_established+0x1175/0x3980 net/ipv4/tcp_input.c:6608 tcp_v4_do_rcv+0xc87/0x10d0 net/ipv4/tcp_ipv4.c:1884 sk_backlog_rcv include/net/sock.h:1185 [inline] __release_sock+0x35a/0x440 net/core/sock.c:3213 release_sock+0x5a/0x220 net/core/sock.c:3795 sk_stream_wait_memory+0x651/0x10c0 net/core/stream.c:149 tcp_sendmsg_locked+0x1558/0x45e0 net/ipv4/tcp.c:1418 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1465 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:859 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] sock_write_iter+0x4ea/0x5a0 net/socket.c:1195 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x1f8/0x250 fs/read_write.c:740 Memory state around the buggy address: ffff88807df49700: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc ffff88807df49780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807df49800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88807df49880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807df49900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================