================================================================== 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 26 at addr ffff888036c9fbea by task syz.4.1108/12162 CPU: 0 UID: 0 PID: 12162 Comm: syz.4.1108 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 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:3962 vt_bind drivers/tty/vt/vt.c:4118 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4190 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+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f324759c799 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:00007f324845d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f3247815fa0 RCX: 00007f324759c799 RDX: 0000000000000084 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007f3247632c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3247816038 R14: 00007f3247815fa0 R15: 00007ffecf21ece8 Allocated by task 5913: 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_node_noprof+0x307/0x850 mm/slub.c:5266 kmalloc_node_noprof include/linux/slab.h:1081 [inline] alloc_slab_obj_exts+0xae/0x260 mm/slub.c:2167 __memcg_slab_post_alloc_hook+0x246/0x990 mm/memcontrol.c:3234 memcg_slab_post_alloc_hook mm/slub.c:2457 [inline] slab_post_alloc_hook mm/slub.c:4549 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_lru_noprof+0x592/0x6e0 mm/slub.c:4885 xas_alloc+0x350/0x460 lib/xarray.c:378 xas_create+0x75a/0x14e0 lib/xarray.c:685 xas_store+0x9e/0x1a30 lib/xarray.c:795 shmem_add_to_page_cache+0x95c/0xcd0 mm/shmem.c:922 shmem_alloc_and_add_folio+0x558/0xd40 mm/shmem.c:1998 shmem_get_folio_gfp+0x6ab/0x1900 mm/shmem.c:2567 shmem_fault+0x1f9/0xa20 mm/shmem.c:2768 __do_fault+0x10d/0x550 mm/memory.c:5364 do_shared_fault mm/memory.c:5863 [inline] do_fault+0x2db/0x1990 mm/memory.c:5937 do_pte_missing mm/memory.c:4477 [inline] handle_pte_fault mm/memory.c:6317 [inline] __handle_mm_fault+0x180f/0x2b60 mm/memory.c:6455 handle_mm_fault+0x36d/0xa20 mm/memory.c:6624 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0xf9c/0x34d0 mm/gup.c:1428 __get_user_pages_locked mm/gup.c:1692 [inline] faultin_page_range+0x1f1/0x9e0 mm/gup.c:1912 madvise_populate mm/madvise.c:974 [inline] madvise_do_behavior+0x354/0x510 mm/madvise.c:1933 do_madvise+0x195/0x240 mm/madvise.c:2028 __do_sys_madvise mm/madvise.c:2037 [inline] __se_sys_madvise mm/madvise.c:2035 [inline] __x64_sys_madvise+0xa9/0x110 mm/madvise.c:2035 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 ffff888036c9fb00 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 50 bytes to the right of allocated 184-byte region [ffff888036c9fb00, ffff888036c9fbb8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x36c9f flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813fe393c0 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 27058000902, free_ts 27057251434 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] __kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5375 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] call_usermodehelper_setup+0xaf/0x360 kernel/umh.c:362 kobject_uevent_env+0x17c1/0x18b0 lib/kobject_uevent.c:628 kernel_add_sysfs_param kernel/params.c:810 [inline] param_sysfs_builtin kernel/params.c:845 [inline] param_sysfs_builtin_init+0x37b/0x3f0 kernel/params.c:981 do_one_initcall+0x11d/0x760 init/main.c:1382 do_initcall_level init/main.c:1444 [inline] do_initcalls init/main.c:1460 [inline] do_basic_setup init/main.c:1479 [inline] kernel_init_freeable+0x6e5/0x7a0 init/main.c:1692 kernel_init+0x1f/0x1e0 init/main.c:1582 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 10 tgid 10 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 vfree.part.0+0x12b/0x9d0 mm/vmalloc.c:3479 vfree mm/vmalloc.c:3456 [inline] delayed_vfree_work+0x8e/0xd0 mm/vmalloc.c:3398 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 Memory state around the buggy address: ffff888036c9fa80: 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc fc ffff888036c9fb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888036c9fb80: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc ^ ffff888036c9fc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888036c9fc80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================