================================================================== 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+0xc74/0xe10 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880a7dcf997 by task syz-executor.4/27168 CPU: 0 PID: 27168 Comm: syz-executor.4 Not tainted 4.19.120-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+0x188/0x20d lib/dump_stack.c:118 print_address_description.cold+0x7c/0x212 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+0x88/0x2b9 mm/kasan/report.c:396 __fb_pad_aligned_buffer include/linux/fb.h:674 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xc74/0xe10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x434/0x4f0 drivers/video/fbdev/core/fbcon.c:1323 do_update_region+0x2cf/0x630 drivers/tty/vt/vt.c:668 redraw_screen+0x5e1/0x870 drivers/tty/vt/vt.c:1026 vc_do_resize+0x108e/0x1380 drivers/tty/vt/vt.c:1312 vt_ioctl+0x1fa2/0x2500 drivers/tty/vt/vt_ioctl.c:901 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c829 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe06cbdac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004f28a0 RCX: 000000000045c829 RDX: 0000000020000000 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000673 R14: 00000000004c9481 R15: 00007fe06cbdb6d4 Allocated by task 6423: set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3703 __kmalloc_reserve.isra.0+0x39/0xe0 net/core/skbuff.c:137 __alloc_skb+0xef/0x5b0 net/core/skbuff.c:205 alloc_skb_fclone include/linux/skbuff.h:1037 [inline] sk_stream_alloc_skb+0xc1/0x850 net/ipv4/tcp.c:874 tcp_sendmsg_locked+0xc44/0x2ff0 net/ipv4/tcp.c:1302 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1452 inet_sendmsg+0x12e/0x590 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:632 sock_write_iter+0x283/0x3c0 net/socket.c:901 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x512/0x760 fs/read_write.c:487 vfs_write+0x206/0x550 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 Freed by task 6423: set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/kasan.c:521 __cache_free mm/slab.c:3503 [inline] kfree+0xce/0x220 mm/slab.c:3822 skb_free_head+0x91/0xb0 net/core/skbuff.c:554 skb_release_data+0x600/0x8c0 net/core/skbuff.c:574 skb_release_all+0x46/0x60 net/core/skbuff.c:631 __kfree_skb+0x11/0x20 net/core/skbuff.c:645 sk_wmem_free_skb include/net/sock.h:1462 [inline] tcp_rtx_queue_unlink_and_free include/net/tcp.h:1751 [inline] tcp_clean_rtx_queue net/ipv4/tcp_input.c:3153 [inline] tcp_ack+0x1d69/0x4e80 net/ipv4/tcp_input.c:3678 tcp_rcv_established+0x12cd/0x1e60 net/ipv4/tcp_input.c:5566 tcp_v4_do_rcv+0x60b/0x8b0 net/ipv4/tcp_ipv4.c:1535 sk_backlog_rcv include/net/sock.h:946 [inline] __release_sock+0x134/0x3a0 net/core/sock.c:2342 release_sock+0x54/0x1c0 net/core/sock.c:2858 tcp_sendmsg+0x36/0x40 net/ipv4/tcp.c:1453 inet_sendmsg+0x12e/0x590 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:632 sock_write_iter+0x283/0x3c0 net/socket.c:901 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x512/0x760 fs/read_write.c:487 vfs_write+0x206/0x550 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 The buggy address belongs to the object at ffff8880a7dcf6c0 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 727 bytes inside of 1024-byte region [ffff8880a7dcf6c0, ffff8880a7dcfac0) The buggy address belongs to the page: page:ffffea00029f7380 count:1 mapcount:0 mapping:ffff88812c39cac0 index:0xffff8880a7dce4c0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea00013a1388 ffffea000244c708 ffff88812c39cac0 raw: ffff8880a7dce4c0 ffff8880a7dce040 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a7dcf880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a7dcf900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a7dcf980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a7dcfa00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a7dcfa80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================