================================================================== 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+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff88809620167c by task syz-executor.5/11888 CPU: 1 PID: 11888 Comm: syz-executor.5 Not tainted 4.19.95-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+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report mm/kasan/report.c:412 [inline] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load1_noabort+0x14/0x20 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+0xd5d/0xf10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x42b/0x4f0 drivers/video/fbdev/core/fbcon.c:1320 con_flush drivers/tty/vt/vt.c:2522 [inline] do_con_write.part.0+0xeb9/0x1eb0 drivers/tty/vt/vt.c:2775 do_con_write drivers/tty/vt/vt.c:2541 [inline] con_write+0x46/0xd0 drivers/tty/vt/vt.c:3110 process_output_block drivers/tty/n_tty.c:593 [inline] n_tty_write+0x3f9/0x1140 drivers/tty/n_tty.c:2331 do_tty_write drivers/tty/tty_io.c:960 [inline] tty_write+0x458/0x7a0 drivers/tty/tty_io.c:1044 __vfs_write+0x114/0x810 fs/read_write.c:485 __kernel_write+0x110/0x390 fs/read_write.c:506 write_pipe_buf+0x15d/0x1f0 fs/splice.c:798 splice_from_pipe_feed fs/splice.c:503 [inline] __splice_from_pipe+0x391/0x7d0 fs/splice.c:627 splice_from_pipe+0x108/0x170 fs/splice.c:662 default_file_splice_write+0x3c/0x90 fs/splice.c:810 do_splice_from fs/splice.c:852 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1025 splice_direct_to_actor+0x367/0x970 fs/splice.c:980 do_splice_direct+0x1da/0x2a0 fs/splice.c:1068 do_sendfile+0x597/0xce0 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64 fs/read_write.c:1494 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1494 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45af49 Code: ad 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd54cd52c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045af49 RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000200000004 R11: 0000000000000246 R12: 00007fd54cd536d4 R13: 00000000004c9b28 R14: 00000000004e2c70 R15: 00000000ffffffff Allocated by task 7519: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x51/0x80 mm/slab.c:3703 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:137 __alloc_skb+0x10b/0x5f0 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:995 [inline] nlmsg_new include/net/netlink.h:511 [inline] rtmsg_ifa+0xe9/0x1d0 net/ipv4/devinet.c:1717 __inet_insert_ifa+0x7f3/0xb00 net/ipv4/devinet.c:526 inet_rtm_newaddr+0xd7c/0x11e0 net/ipv4/devinet.c:918 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:4768 netlink_rcv_skb+0x17d/0x460 net/netlink/af_netlink.c:2454 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:4786 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x53a/0x730 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:632 __sys_sendto+0x262/0x380 net/socket.c:1787 __do_sys_sendto net/socket.c:1799 [inline] __se_sys_sendto net/socket.c:1795 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1795 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7519: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 skb_free_head+0x99/0xc0 net/core/skbuff.c:554 skb_release_data+0x619/0x8d0 net/core/skbuff.c:574 skb_release_all+0x4d/0x60 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] consume_skb net/core/skbuff.c:705 [inline] consume_skb+0xe2/0x390 net/core/skbuff.c:699 netlink_broadcast_filtered+0x316/0xb30 net/netlink/af_netlink.c:1519 netlink_broadcast net/netlink/af_netlink.c:1541 [inline] nlmsg_multicast include/net/netlink.h:591 [inline] nlmsg_notify+0x16c/0x1b0 net/netlink/af_netlink.c:2497 rtnl_notify+0xc5/0xf0 net/core/rtnetlink.c:736 rtmsg_ifa+0x144/0x1d0 net/ipv4/devinet.c:1728 __inet_insert_ifa+0x7f3/0xb00 net/ipv4/devinet.c:526 inet_rtm_newaddr+0xd7c/0x11e0 net/ipv4/devinet.c:918 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:4768 netlink_rcv_skb+0x17d/0x460 net/netlink/af_netlink.c:2454 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:4786 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x53a/0x730 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:632 __sys_sendto+0x262/0x380 net/socket.c:1787 __do_sys_sendto net/socket.c:1799 [inline] __se_sys_sendto net/socket.c:1795 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1795 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888096201580 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 252 bytes inside of 512-byte region [ffff888096201580, ffff888096201780) The buggy address belongs to the page: page:ffffea0002588040 count:1 mapcount:0 mapping:ffff88812c31c940 index:0xffff888096201a80 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea0002a56d88 ffffea000184ed08 ffff88812c31c940 raw: ffff888096201a80 ffff888096201080 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888096201500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888096201580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888096201600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888096201680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096201700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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