================================================================== BUG: KASAN: use-after-free in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: use-after-free in fbcon_prepare_logo+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:646 Read of size 26 at addr ffff88806d3cafee by task syz.4.8235/31353 CPU: 0 UID: 0 PID: 31353 Comm: syz.4.8235 Tainted: G U W L XTNJ syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [W]=WARN, [L]=SOFTLOCKUP, [X]=AUX, [T]=RANDSTRUCT, [N]=TEST, [J]=FWCTL 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: 0033:0x7f8a1819c799 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:00007f8a163b4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f8a18416180 RCX: 00007f8a1819c799 RDX: 0000000000000084 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007f8a18232c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8a18416218 R14: 00007f8a18416180 R15: 00007ffcdd5e1c78 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x226 pfn:0x6d3ca flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f0(buddy) raw: 00fff00000000000 ffffea000084f188 ffffea0002b85cc8 0000000000000000 raw: 0000000000000226 0000000000000000 00000000f0000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2cc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN), pid 30836, tgid 30828 (syz.1.8109), ts 1231284040839, free_ts 1232016990901 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_pages_noprof+0xb/0x1b0 mm/page_alloc.c:5284 __alloc_pages_node_noprof include/linux/gfp.h:289 [inline] alloc_pages_node_noprof include/linux/gfp.h:316 [inline] pcpu_alloc_pages mm/percpu-vm.c:95 [inline] pcpu_populate_chunk+0x118/0x990 mm/percpu-vm.c:285 pcpu_alloc_noprof+0x833/0x1c50 mm/percpu.c:1876 bpf_map_alloc_percpu+0x9a/0xf0 kernel/bpf/syscall.c:583 prealloc_init kernel/bpf/hashtab.c:334 [inline] htab_map_alloc+0x1054/0x14e0 kernel/bpf/hashtab.c:636 map_create+0x84e/0x2ba0 kernel/bpf/syscall.c:1507 __sys_bpf+0x2091/0x4b90 kernel/bpf/syscall.c:6210 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x7b/0xc0 kernel/bpf/syscall.c:6339 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 page last free pid 29801 tgid 29801 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 pcpu_free_pages.isra.0+0x13c/0x1c0 mm/percpu-vm.c:65 pcpu_reclaim_populated mm/percpu.c:2158 [inline] pcpu_balance_workfn+0x24e/0xdd0 mm/percpu.c:2214 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: ffff88806d3cae80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88806d3caf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88806d3caf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88806d3cb000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88806d3cb080: 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================