================================================================== BUG: KASAN: slab-out-of-bounds in vc_con_write_normal drivers/tty/vt/vt.c:3135 [inline] BUG: KASAN: slab-out-of-bounds in do_con_write+0x386f/0x8540 drivers/tty/vt/vt.c:3226 Write of size 2 at addr ffff8880358f9a60 by task syz.0.1898/14645 CPU: 0 UID: 0 PID: 14645 Comm: syz.0.1898 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [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 vc_con_write_normal drivers/tty/vt/vt.c:3135 [inline] do_con_write+0x386f/0x8540 drivers/tty/vt/vt.c:3226 con_write+0x23/0xb0 drivers/tty/vt/vt.c:3558 process_output_block drivers/tty/n_tty.c:557 [inline] n_tty_write+0x44f/0x12d0 drivers/tty/n_tty.c:2366 iterate_tty_write drivers/tty/tty_io.c:1006 [inline] file_tty_write.isra.0+0x4d2/0x890 drivers/tty/tty_io.c:1081 tty_write drivers/tty/tty_io.c:1102 [inline] redirected_tty_write drivers/tty/tty_io.c:1125 [inline] redirected_tty_write+0xd4/0x120 drivers/tty/tty_io.c:1105 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+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8b18b9c799 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:00007f8b19b35028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f8b18e15fa0 RCX: 00007f8b18b9c799 RDX: 000000000000fdef RSI: 0000200000000000 RDI: 0000000000000005 RBP: 00007f8b18c32c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8b18e16038 R14: 00007f8b18e15fa0 R15: 00007ffff9e56278 Allocated by task 5193: 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:5260 [inline] __kmalloc_noprof+0x301/0x850 mm/slub.c:5272 kmalloc_noprof include/linux/slab.h:954 [inline] tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x2af/0x3c0 security/tomoyo/file.c:776 tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334 security_file_open+0xb5/0x1e0 security/security.c:2636 do_dentry_open+0x5aa/0x1660 fs/open.c:926 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4830 do_file_open+0x20e/0x430 fs/namei.c:4859 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 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 Freed by task 5193: 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:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1f6/0x6b0 mm/slub.c:6483 tomoyo_realpath_from_path+0x19c/0x690 security/tomoyo/realpath.c:286 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x2af/0x3c0 security/tomoyo/file.c:776 tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334 security_file_open+0xb5/0x1e0 security/security.c:2636 do_dentry_open+0x5aa/0x1660 fs/open.c:926 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4830 do_file_open+0x20e/0x430 fs/namei.c:4859 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 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 ffff8880358f8000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 2656 bytes to the right of allocated 4096-byte region [ffff8880358f8000, ffff8880358f9000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x358f8 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 ffff88813fe3d140 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fe3d140 dead000000000100 dead000000000122 head: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000d63e01 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 33, tgid 33 (kworker/u8:2), ts 551076540020, free_ts 550996176656 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:3292 [inline] allocate_slab mm/slub.c:3481 [inline] new_slab+0xa6/0x6b0 mm/slub.c:3539 refill_objects+0x26b/0x400 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x1ab/0x660 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] __do_kmalloc_node mm/slub.c:5259 [inline] __kmalloc_node_track_caller_noprof+0x694/0x850 mm/slub.c:5368 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:635 __alloc_skb+0x185/0x710 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1383 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline] nsim_dev_trap_report_work+0x2af/0xd10 drivers/net/netdevsim/dev.c:922 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276 process_scheduled_works kernel/workqueue.c:3359 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page last free pid 5810 tgid 5810 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 tcp_v4_rcv+0x2de5/0x4680 net/ipv4/tcp_ipv4.c:2319 ip_protocol_deliver_rcu+0xba/0x4d0 net/ipv4/ip_input.c:207 ip_local_deliver_finish+0x3f2/0x6e0 net/ipv4/ip_input.c:241 NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] ip_local_deliver+0x19a/0x1f0 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:480 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:584 [inline] ip_list_rcv_finish+0xa14/0xce0 net/ipv4/ip_input.c:636 ip_sublist_rcv net/ipv4/ip_input.c:644 [inline] ip_list_rcv+0x338/0x450 net/ipv4/ip_input.c:678 __netif_receive_skb_list_ptype net/core/dev.c:6207 [inline] __netif_receive_skb_list_core+0x74c/0x940 net/core/dev.c:6254 __netif_receive_skb_list net/core/dev.c:6306 [inline] netif_receive_skb_list_internal+0x722/0xd40 net/core/dev.c:6397 gro_normal_list include/net/gro.h:523 [inline] gro_normal_list include/net/gro.h:519 [inline] gro_flush_normal include/net/gro.h:531 [inline] napi_complete_done+0x221/0x940 net/core/dev.c:6765 Memory state around the buggy address: ffff8880358f9900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880358f9980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880358f9a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880358f9a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880358f9b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================