================================================================== BUG: KASAN: slab-use-after-free in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: slab-use-after-free in fbcon_prepare_logo+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:623 Read of size 256 at addr ffff88805b3923c0 by task syz.3.1129/11301 CPU: 0 UID: 0 PID: 11301 Comm: syz.3.1129 Tainted: G U syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:194 [inline] kasan_check_range+0x100/0x1b0 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+0xa03/0xc70 drivers/video/fbdev/core/fbcon.c:623 fbcon_init+0xd77/0x1900 drivers/video/fbdev/core/fbcon.c:1156 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1020 do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3960 vt_bind drivers/tty/vt/vt.c:4116 [inline] store_bind+0x61d/0x760 drivers/tty/vt/vt.c:4188 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352 iter_file_splice_write+0xa24/0x12e0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1161 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1230 do_sendfile+0xb06/0xe50 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64 fs/read_write.c:1417 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f39a718f6c9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f39a8052038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f39a73e6090 RCX: 00007f39a718f6c9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 00007f39a7211f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f39a73e6128 R14: 00007f39a73e6090 R15: 00007fffa9884dc8 Allocated by task 11264: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4970 [inline] slab_alloc_node mm/slub.c:5280 [inline] kmem_cache_alloc_noprof+0x250/0x6e0 mm/slub.c:5287 anon_vma_chain_alloc mm/rmap.c:141 [inline] anon_vma_fork+0x200/0x620 mm/rmap.c:363 dup_mmap+0x151f/0x2280 mm/mmap.c:1797 dup_mm kernel/fork.c:1489 [inline] copy_mm kernel/fork.c:1541 [inline] copy_process+0x3f0c/0x76a0 kernel/fork.c:2181 kernel_clone+0xfc/0x930 kernel/fork.c:2609 __do_sys_clone+0xce/0x120 kernel/fork.c:2750 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 11290: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2539 [inline] slab_free mm/slub.c:6630 [inline] kmem_cache_free+0x2d4/0x6c0 mm/slub.c:6740 anon_vma_chain_free mm/rmap.c:146 [inline] unlink_anon_vmas+0x458/0x820 mm/rmap.c:446 free_pgtables+0x212/0xc00 mm/memory.c:413 exit_mmap+0x3f4/0xb90 mm/mmap.c:1291 __mmput+0x12a/0x410 kernel/fork.c:1133 mmput+0x62/0x70 kernel/fork.c:1156 exec_mmap fs/exec.c:901 [inline] begin_new_exec+0x15b3/0x3ab0 fs/exec.c:1156 load_elf_binary+0x8e7/0x4fe0 fs/binfmt_elf.c:1010 search_binary_handler fs/exec.c:1670 [inline] exec_binprm fs/exec.c:1702 [inline] bprm_execve fs/exec.c:1754 [inline] bprm_execve+0x8be/0x1640 fs/exec.c:1730 do_execveat_common.isra.0+0x4a5/0x610 fs/exec.c:1860 do_execve fs/exec.c:1934 [inline] __do_sys_execve fs/exec.c:2010 [inline] __se_sys_execve fs/exec.c:2005 [inline] __x64_sys_execve+0x8e/0xb0 fs/exec.c:2005 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88805b392380 which belongs to the cache anon_vma_chain of size 80 The buggy address is located 64 bytes inside of freed 80-byte region [ffff88805b392380, ffff88805b3923d0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5b392 memcg:ffff88805b388801 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff888140407280 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000240024 00000000f5000000 ffff88805b388801 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 11264, tgid 11264 (dhcpcd-run-hook), ts 363932088408, free_ts 363922101274 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3055 [inline] allocate_slab mm/slub.c:3228 [inline] new_slab+0x24a/0x360 mm/slub.c:3282 ___slab_alloc+0xdae/0x1a60 mm/slub.c:4651 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4770 __slab_alloc_node mm/slub.c:4846 [inline] slab_alloc_node mm/slub.c:5268 [inline] kmem_cache_alloc_noprof+0x43f/0x6e0 mm/slub.c:5287 anon_vma_chain_alloc mm/rmap.c:141 [inline] anon_vma_fork+0x200/0x620 mm/rmap.c:363 dup_mmap+0x151f/0x2280 mm/mmap.c:1797 dup_mm kernel/fork.c:1489 [inline] copy_mm kernel/fork.c:1541 [inline] copy_process+0x3f0c/0x76a0 kernel/fork.c:2181 kernel_clone+0xfc/0x930 kernel/fork.c:2609 __do_sys_clone+0xce/0x120 kernel/fork.c:2750 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 11281 tgid 11274 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906 vfree+0x1fd/0xb50 mm/vmalloc.c:3440 snd_dma_free_pages+0x54/0x70 sound/core/memalloc.c:132 do_free_pages sound/core/pcm_memory.c:88 [inline] do_free_pages sound/core/pcm_memory.c:83 [inline] snd_pcm_lib_free_pages+0x172/0x390 sound/core/pcm_memory.c:495 do_hw_free sound/core/pcm_native.c:911 [inline] snd_pcm_release_substream.part.0+0x2a8/0x340 sound/core/pcm_native.c:2735 snd_pcm_release_substream+0x5b/0x70 sound/core/pcm_native.c:2729 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2396 [inline] snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2388 [inline] snd_pcm_oss_release+0x16f/0x310 sound/core/oss/pcm_oss.c:2575 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xec/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88805b392280: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fc fc ffff88805b392300: fc fc fa fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff88805b392380: fa fb fb fb fb fb fb fb fb fb fc fc fc fc fa fb ^ ffff88805b392400: fb fb fb fb fb fb fb fb fc fc fc fc fa fb fb fb ffff88805b392480: fb fb fb fb fb fb fc fc fc fc fa fb fb fb fb fb ==================================================================