================================================================== BUG: KASAN: slab-out-of-bounds in vc_con_write_normal drivers/tty/vt/vt.c:3238 [inline] BUG: KASAN: slab-out-of-bounds in do_con_write+0x394b/0x4a30 drivers/tty/vt/vt.c:3329 Write of size 2 at addr ffff88805317ded0 by task syz.5.3525/18737 CPU: 0 UID: 0 PID: 18737 Comm: syz.5.3525 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 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/0x1c0 mm/kasan/report.c:595 vc_con_write_normal drivers/tty/vt/vt.c:3238 [inline] do_con_write+0x394b/0x4a30 drivers/tty/vt/vt.c:3329 con_write+0x23/0xb0 drivers/tty/vt/vt.c:3661 process_output_block drivers/tty/n_tty.c:557 [inline] n_tty_write+0x431/0x1160 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 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1e1639e019 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:00007f1e1719c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f1e16625fa0 RCX: 00007f1e1639e019 RDX: 0000000000001006 RSI: 0000200000001980 RDI: 0000000000000006 RBP: 00007f1e1643500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1e16626038 R14: 00007f1e16625fa0 R15: 00007ffe88a5d3a8 Allocated by task 15666: 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:5334 [inline] __kmalloc_noprof+0x322/0x820 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_number_perm+0x23c/0x580 security/tomoyo/file.c:728 tomoyo_path_mkdir+0x9b/0xe0 security/tomoyo/tomoyo.c:179 security_path_mkdir+0x154/0x2e0 security/security.c:1450 filename_mkdirat+0x168/0x5e0 fs/namei.c:5306 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat fs/namei.c:5327 [inline] __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15666: 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:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x22b/0x6c0 mm/slub.c:6692 tomoyo_realpath_from_path+0x19c/0x690 security/tomoyo/realpath.c:286 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_number_perm+0x23c/0x580 security/tomoyo/file.c:728 tomoyo_path_mkdir+0x9b/0xe0 security/tomoyo/tomoyo.c:179 security_path_mkdir+0x154/0x2e0 security/security.c:1450 filename_mkdirat+0x168/0x5e0 fs/namei.c:5306 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat fs/namei.c:5327 [inline] __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88805317c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 3792 bytes to the right of allocated 4096-byte region [ffff88805317c000, ffff88805317d000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x53178 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 ffff88813fe28140 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fe28140 dead000000000100 dead000000000122 head: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 17914, tgid 17913 (syz.1.3309), ts 931643002120, free_ts 861452343797 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab mm/slub.c:3380 [inline] new_slab+0xa2/0x640 mm/slub.c:3426 refill_objects+0xe3/0x410 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_noprof+0x66d/0x820 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] vc_do_resize+0x1dd/0xeb0 drivers/tty/vt/vt.c:1211 vc_resize include/linux/vt_kern.h:49 [inline] vgacon_init+0x386/0x440 drivers/video/console/vgacon.c:392 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1048 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:4054 do_unbind_con_driver+0x536/0x6a0 drivers/tty/vt/vt.c:4163 vt_unbind drivers/tty/vt/vt.c:4249 [inline] store_bind+0x3f8/0x730 drivers/tty/vt/vt.c:4284 dev_attr_store+0x58/0x80 drivers/base/core.c:2505 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 page last free pid 5272 tgid 5272 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_pages_ok+0x73b/0xfe0 mm/page_alloc.c:1584 proc_sys_call_handler+0x4af/0x5a0 fs/proc/proc_sysctl.c:612 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x82e/0xb40 fs/read_write.c:574 ksys_read+0x12a/0x250 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88805317dd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88805317de00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88805317de80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88805317df00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88805317df80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================