================================================================== 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 ffff8880a001f988 by task syz-executor.5/17240 CPU: 1 PID: 17240 Comm: syz-executor.5 Not tainted 4.19.183-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/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 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:1269 con_flush drivers/tty/vt/vt.c:2559 [inline] do_con_write+0xbcd/0x1d90 drivers/tty/vt/vt.c:2809 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3145 n_tty_write+0xa03/0xff0 drivers/tty/n_tty.c:2354 do_tty_write drivers/tty/tty_io.c:960 [inline] tty_write+0x496/0x810 drivers/tty/tty_io.c:1044 do_loop_readv_writev fs/read_write.c:704 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_write+0x461/0x5d0 fs/read_write.c:962 vfs_writev+0x153/0x2e0 fs/read_write.c:1005 do_writev+0x136/0x330 fs/read_write.c:1040 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466459 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5e84c3b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459 RDX: 0000000000000001 RSI: 00000000200005c0 RDI: 0000000000000006 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffd9c2a242f R14: 00007f5e84c3b300 R15: 0000000000022000 Allocated by task 8092: __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] __alloc_skb+0xae/0x560 net/core/skbuff.c:205 __napi_alloc_skb+0x74/0x300 net/core/skbuff.c:478 napi_alloc_skb include/linux/skbuff.h:2724 [inline] page_to_skb+0x76/0x890 drivers/net/virtio_net.c:396 receive_mergeable drivers/net/virtio_net.c:936 [inline] receive_buf+0x25c7/0x6330 drivers/net/virtio_net.c:1045 virtnet_receive drivers/net/virtio_net.c:1336 [inline] virtnet_poll+0x568/0xd70 drivers/net/virtio_net.c:1441 napi_poll net/core/dev.c:6272 [inline] net_rx_action+0x4ac/0xfb0 net/core/dev.c:6338 __do_softirq+0x265/0x980 kernel/softirq.c:292 Freed by task 8092: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 skb_free_head net/core/skbuff.c:563 [inline] skb_release_data+0x6de/0x920 net/core/skbuff.c:583 skb_release_all net/core/skbuff.c:640 [inline] __kfree_skb+0x46/0x60 net/core/skbuff.c:654 tcp_rcv_established+0x13c1/0x1ea0 net/ipv4/tcp_input.c:5591 tcp_v4_do_rcv+0x5d6/0x870 net/ipv4/tcp_ipv4.c:1547 tcp_v4_rcv+0x2c03/0x3b80 net/ipv4/tcp_ipv4.c:1832 ip_local_deliver_finish+0x495/0xc00 net/ipv4/ip_input.c:215 NF_HOOK include/linux/netfilter.h:289 [inline] ip_local_deliver+0x188/0x500 net/ipv4/ip_input.c:256 dst_input include/net/dst.h:461 [inline] ip_rcv_finish+0x1ca/0x2e0 net/ipv4/ip_input.c:414 NF_HOOK include/linux/netfilter.h:289 [inline] ip_rcv+0xca/0x3c0 net/ipv4/ip_input.c:524 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:4954 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5066 netif_receive_skb_internal+0xf0/0x3f0 net/core/dev.c:5156 napi_skb_finish net/core/dev.c:5600 [inline] napi_gro_receive+0x2e6/0x450 net/core/dev.c:5631 receive_buf+0xf1b/0x6330 drivers/net/virtio_net.c:1072 virtnet_receive drivers/net/virtio_net.c:1336 [inline] virtnet_poll+0x568/0xd70 drivers/net/virtio_net.c:1441 napi_poll net/core/dev.c:6272 [inline] net_rx_action+0x4ac/0xfb0 net/core/dev.c:6338 __do_softirq+0x265/0x980 kernel/softirq.c:292 The buggy address belongs to the object at ffff8880a001f800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 392 bytes inside of 512-byte region [ffff8880a001f800, ffff8880a001fa00) The buggy address belongs to the page: page:ffffea00028007c0 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffffea00026b4688 ffffea0002577b48 ffff88813bff0940 raw: 0000000000000000 ffff8880a001f080 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a001f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a001f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a001f980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a001fa00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a001fa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================