================================================================== BUG: KASAN: use-after-free in __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] BUG: KASAN: use-after-free in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: use-after-free in bit_putcs+0xbaf/0xd10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff888095c3a644 by task syz-executor.2/2593 CPU: 1 PID: 2593 Comm: syz-executor.2 Not tainted 4.19.134-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2fe lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1c7 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load1_noabort+0x88/0x90 mm/kasan/report.c:430 __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xbaf/0xd10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x336/0x4f0 drivers/video/fbdev/core/fbcon.c:1323 con_flush drivers/tty/vt/vt.c:2552 [inline] do_con_write+0xbcd/0x1d90 drivers/tty/vt/vt.c:2802 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3138 process_output_block drivers/tty/n_tty.c:593 [inline] n_tty_write+0x3c0/0xff0 drivers/tty/n_tty.c:2331 do_tty_write drivers/tty/tty_io.c:960 [inline] tty_write+0x496/0x810 drivers/tty/tty_io.c:1044 __vfs_write+0xf7/0x770 fs/read_write.c:485 vfs_write+0x1f3/0x540 fs/read_write.c:549 ksys_write+0x12b/0x2a0 fs/read_write.c:599 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c369 Code: 8d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7ff7aabc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000037080 RCX: 000000000045c369 RDX: 0000000000001006 RSI: 0000000020001040 RDI: 0000000000000004 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007ffc6ecc534f R14: 00007f7ff7aac9c0 R15: 000000000078bf0c Allocated by task 137: __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3703 __kmalloc_reserve net/core/skbuff.c:137 [inline] pskb_expand_head+0x159/0xf20 net/core/skbuff.c:1464 __skb_cow include/linux/skbuff.h:2951 [inline] skb_cow_head include/linux/skbuff.h:2985 [inline] batadv_skb_head_push+0xed/0x280 net/batman-adv/soft-interface.c:86 batadv_send_skb_packet+0x114/0x600 net/batman-adv/send.c:98 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:578 [inline] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:604 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x6b1/0x7a0 net/batman-adv/bat_iv_ogm.c:1857 process_one_work+0x864/0x1570 kernel/workqueue.c:2155 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298 kthread+0x30b/0x410 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Freed by task 137: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 skb_free_head net/core/skbuff.c:554 [inline] skb_release_data+0x6de/0x920 net/core/skbuff.c:574 skb_release_all net/core/skbuff.c:631 [inline] __kfree_skb net/core/skbuff.c:645 [inline] consume_skb+0x113/0x3d0 net/core/skbuff.c:705 packet_rcv+0xea/0x1480 net/packet/af_packet.c:2146 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:4954 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5066 process_backlog+0x239/0x6f0 net/core/dev.c:5848 napi_poll net/core/dev.c:6271 [inline] net_rx_action+0x4ac/0xfb0 net/core/dev.c:6337 __do_softirq+0x26c/0x9a0 kernel/softirq.c:292 The buggy address belongs to the object at ffff888095c3a4c0 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 388 bytes inside of 1024-byte region [ffff888095c3a4c0, ffff888095c3a8c0) The buggy address belongs to the page: page:ffffea0002570e80 count:1 mapcount:0 mapping:ffff88812c39cac0 index:0xffff888095c3a4c0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea0002337388 ffffea00023c7f88 ffff88812c39cac0 raw: ffff888095c3a4c0 ffff888095c3a040 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888095c3a500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095c3a580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888095c3a600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888095c3a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095c3a700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================