================================================================== 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:630 Read of size 126 at addr ffff8880258e4bae by task syz.1.1942/16468 CPU: 1 UID: 0 PID: 16468 Comm: syz.1.1942 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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:183 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189 __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:630 fbcon_init+0xd77/0x1900 drivers/video/fbdev/core/fbcon.c:1163 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1019 do_bind_con_driver.isra.0+0x57a/0xbf0 drivers/tty/vt/vt.c:3915 vt_bind drivers/tty/vt/vt.c:4071 [inline] store_bind+0x61d/0x760 drivers/tty/vt/vt.c:4143 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x354/0x510 fs/kernfs/file.c:334 iter_file_splice_write+0xa24/0x12e0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x18f/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/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9b9958ebe9 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:00007f9b9a4e2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f9b997b5fa0 RCX: 00007f9b9958ebe9 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 00007f9b99611e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9b997b6038 R14: 00007f9b997b5fa0 R15: 00007fffa80dfef8 Allocated by task 15: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4365 [inline] __kmalloc_noprof+0x223/0x510 mm/slub.c:4377 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] ieee802_11_parse_elems_full+0x1db/0x3780 net/mac80211/parse.c:1011 ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2462 [inline] ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2469 [inline] ieee80211_inform_bss+0x10b/0x1140 net/mac80211/scan.c:79 rdev_inform_bss net/wireless/rdev-ops.h:418 [inline] cfg80211_inform_single_bss_data+0x8ea/0x1df0 net/wireless/scan.c:2379 cfg80211_inform_bss_data+0x224/0x3bd0 net/wireless/scan.c:3234 cfg80211_inform_bss_frame_data+0x26f/0x750 net/wireless/scan.c:3325 ieee80211_bss_info_update+0x310/0xab0 net/mac80211/scan.c:226 ieee80211_scan_rx+0x4cf/0xb30 net/mac80211/scan.c:355 __ieee80211_rx_handle_packet net/mac80211/rx.c:5186 [inline] ieee80211_rx_list+0x1bdb/0x2980 net/mac80211/rx.c:5423 ieee80211_rx_napi+0xdc/0x410 net/mac80211/rx.c:5446 ieee80211_rx include/net/mac80211.h:5210 [inline] ieee80211_handle_queued_frames+0xd5/0x130 net/mac80211/main.c:453 tasklet_action_common+0x284/0x400 kernel/softirq.c:829 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579 run_ksoftirqd kernel/softirq.c:968 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960 smpboot_thread_fn+0x3f4/0xae0 kernel/smpboot.c:160 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 15: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4879 ieee80211_inform_bss+0x77c/0x1140 net/mac80211/scan.c:160 rdev_inform_bss net/wireless/rdev-ops.h:418 [inline] cfg80211_inform_single_bss_data+0x8ea/0x1df0 net/wireless/scan.c:2379 cfg80211_inform_bss_data+0x224/0x3bd0 net/wireless/scan.c:3234 cfg80211_inform_bss_frame_data+0x26f/0x750 net/wireless/scan.c:3325 ieee80211_bss_info_update+0x310/0xab0 net/mac80211/scan.c:226 ieee80211_scan_rx+0x4cf/0xb30 net/mac80211/scan.c:355 __ieee80211_rx_handle_packet net/mac80211/rx.c:5186 [inline] ieee80211_rx_list+0x1bdb/0x2980 net/mac80211/rx.c:5423 ieee80211_rx_napi+0xdc/0x410 net/mac80211/rx.c:5446 ieee80211_rx include/net/mac80211.h:5210 [inline] ieee80211_handle_queued_frames+0xd5/0x130 net/mac80211/main.c:453 tasklet_action_common+0x284/0x400 kernel/softirq.c:829 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579 run_ksoftirqd kernel/softirq.c:968 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960 smpboot_thread_fn+0x3f4/0xae0 kernel/smpboot.c:160 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff8880258e4800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 942 bytes inside of freed 1024-byte region [ffff8880258e4800, ffff8880258e4c00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x258e0 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b841dc0 ffffea0001143c00 dead000000000003 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b841dc0 ffffea0001143c00 dead000000000003 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000963801 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1112, tgid 1112 (kworker/u8:5), ts 475800234631, free_ts 475771010205 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x247/0x330 mm/slub.c:2709 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] __do_kmalloc_node mm/slub.c:4364 [inline] __kmalloc_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4384 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:600 pskb_expand_head+0x238/0x1030 net/core/skbuff.c:2240 __skb_cow include/linux/skbuff.h:3806 [inline] skb_cow_head include/linux/skbuff.h:3840 [inline] batadv_skb_head_push+0xf5/0x290 net/batman-adv/mesh-interface.c:71 batadv_send_skb_packet+0x11b/0x780 net/batman-adv/send.c:85 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:392 [inline] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:420 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x734/0x920 net/batman-adv/bat_iv_ogm.c:1702 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 page last free pid 10548 tgid 10548 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895 discard_slab mm/slub.c:2753 [inline] __put_partials+0x165/0x1c0 mm/slub.c:3218 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4236 new_handle fs/jbd2/transaction.c:457 [inline] jbd2__journal_start+0x193/0x6a0 fs/jbd2/transaction.c:484 __ext4_journal_start_sb+0x195/0x690 fs/ext4/ext4_jbd2.c:115 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline] ext4_dirty_inode+0xa1/0x130 fs/ext4/inode.c:6535 __mark_inode_dirty+0x1ee/0xe40 fs/fs-writeback.c:2527 generic_update_time+0xcf/0xf0 fs/inode.c:2063 inode_update_time fs/inode.c:2076 [inline] __file_update_time fs/inode.c:2304 [inline] file_update_time+0x17d/0x1c0 fs/inode.c:2334 ext4_page_mkwrite+0x33d/0x1880 fs/ext4/inode.c:6704 do_page_mkwrite+0x174/0x380 mm/memory.c:3361 do_shared_fault mm/memory.c:5649 [inline] do_fault mm/memory.c:5711 [inline] do_pte_missing+0x29d/0x3ba0 mm/memory.c:4234 handle_pte_fault mm/memory.c:6052 [inline] __handle_mm_fault+0x152a/0x2a50 mm/memory.c:6195 Memory state around the buggy address: ffff8880258e4a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880258e4b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880258e4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880258e4c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880258e4c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================