================================================================== 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 ffff88803478f3ea by task syz.2.1630/14224 CPU: 0 UID: 0 PID: 14224 Comm: syz.2.1630 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: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 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: 0033:0x7fbe3e79c799 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:00007fbe3f5af028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fbe3ea16270 RCX: 00007fbe3e79c799 RDX: 0000000000000084 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007fbe3e832c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbe3ea16308 R14: 00007fbe3ea16270 R15: 00007ffd655b1b28 Allocated by task 13118: 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 kmalloc_node_noprof include/linux/slab.h:1077 [inline] blk_alloc_flush_queue+0xaa/0x2d0 block/blk-flush.c:485 blk_mq_init_hctx block/blk-mq.c:3998 [inline] blk_mq_alloc_and_init_hctx+0x2db/0x1000 block/blk-mq.c:4537 __blk_mq_realloc_hw_ctxs+0x382/0x820 block/blk-mq.c:4584 blk_mq_realloc_hw_ctxs block/blk-mq.c:4621 [inline] blk_mq_init_allocated_queue+0x308/0x1440 block/blk-mq.c:4651 blk_mq_alloc_queue+0x1bd/0x290 block/blk-mq.c:4433 __blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4476 add_mtd_blktrans_dev+0x7ad/0x1520 drivers/mtd/mtd_blkdevs.c:343 mtdblock_add_mtd+0x1cc/0x270 drivers/mtd/mtdblock.c:333 blktrans_notify_add drivers/mtd/mtd_blkdevs.c:464 [inline] blktrans_notify_add+0xa2/0xf0 drivers/mtd/mtd_blkdevs.c:456 add_mtd_device+0xb1a/0x17a0 drivers/mtd/mtdcore.c:820 mtd_add_partition+0x30a/0x660 drivers/mtd/mtdpart.c:279 mtdchar_blkpg_ioctl+0x207/0x250 drivers/mtd/mtdchar.c:562 mtdchar_ioctl+0x1670/0x1fd0 drivers/mtd/mtdchar.c:1218 mtdchar_unlocked_ioctl+0xb0/0xf0 drivers/mtd/mtdchar.c:1241 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 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 ffff88803478f300 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 90 bytes to the right of allocated 144-byte region [ffff88803478f300, ffff88803478f390) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3478f flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813fe3c3c0 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 20732915110, free_ts 20705847568 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: ffff88803478f280: 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc fc ffff88803478f300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88803478f380: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88803478f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88803478f480: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================