================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff8880a64811a0 by task syz-executor.5/27063 CPU: 1 PID: 27063 Comm: syz-executor.5 Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393 __fb_pad_aligned_buffer include/linux/fb.h:663 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x3bb/0x480 drivers/video/fbdev/core/fbcon.c:1301 do_update_region+0x34b/0x5b0 drivers/tty/vt/vt.c:373 redraw_screen+0x562/0x760 drivers/tty/vt/vt.c:705 vc_do_resize+0xbe0/0xde0 drivers/tty/vt/vt.c:967 vt_ioctl+0x1a64/0x1f20 drivers/tty/vt/vt_ioctl.c:901 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45cb29 RSP: 002b:00007fadbec99c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004f3660 RCX: 000000000045cb29 RDX: 0000000020000000 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000680 R14: 00000000004c9884 R15: 00007fadbec9a6d4 Allocated by task 10294: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15a/0x400 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] fbcon_set_font+0x2f8/0x7c0 drivers/video/fbdev/core/fbcon.c:2621 con_font_set drivers/tty/vt/vt.c:4182 [inline] con_font_op+0xb73/0xf70 drivers/tty/vt/vt.c:4247 vt_ioctl+0x736/0x1f20 drivers/tty/vt/vt_ioctl.c:928 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 6325: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 skb_free_head+0x83/0xa0 net/core/skbuff.c:554 skb_release_data+0x57e/0x7d0 net/core/skbuff.c:574 skb_release_all+0x46/0x60 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] consume_skb+0xa7/0x330 net/core/skbuff.c:705 __dev_kfree_skb_any+0x7a/0xa0 net/core/dev.c:2533 dev_consume_skb_any include/linux/netdevice.h:3276 [inline] free_old_xmit_skbs.isra.0+0x178/0x2a0 drivers/net/virtio_net.c:1137 start_xmit+0x148/0x13f0 drivers/net/virtio_net.c:1299 __netdev_start_xmit include/linux/netdevice.h:4039 [inline] netdev_start_xmit include/linux/netdevice.h:4048 [inline] xmit_one net/core/dev.c:3009 [inline] dev_hard_start_xmit+0x186/0x880 net/core/dev.c:3025 sch_direct_xmit+0x256/0x4f0 net/sched/sch_generic.c:186 __dev_xmit_skb net/core/dev.c:3218 [inline] __dev_queue_xmit+0x1b8d/0x25a0 net/core/dev.c:3493 neigh_hh_output include/net/neighbour.h:490 [inline] neigh_output include/net/neighbour.h:498 [inline] ip_finish_output2+0xac5/0x1430 net/ipv4/ip_output.c:229 ip_finish_output+0x471/0xc20 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:239 [inline] ip_output+0x1cd/0x510 net/ipv4/ip_output.c:405 dst_output include/net/dst.h:462 [inline] ip_local_out+0x93/0x170 net/ipv4/ip_output.c:124 ip_queue_xmit+0x7ca/0x1a70 net/ipv4/ip_output.c:504 __tcp_transmit_skb+0x1831/0x2dc0 net/ipv4/tcp_output.c:1131 tcp_transmit_skb net/ipv4/tcp_output.c:1147 [inline] tcp_write_xmit+0x56a/0x49a0 net/ipv4/tcp_output.c:2391 __tcp_push_pending_frames+0xa0/0x230 net/ipv4/tcp_output.c:2572 tcp_push+0x3fd/0x5f0 net/ipv4/tcp.c:715 tcp_sendmsg_locked+0x21f0/0x2ef0 net/ipv4/tcp.c:1426 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1457 inet_sendmsg+0x116/0x4d0 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 sock_write_iter+0x22c/0x370 net/socket.c:925 call_write_iter include/linux/fs.h:1778 [inline] new_sync_write fs/read_write.c:469 [inline] __vfs_write+0x44e/0x630 fs/read_write.c:482 vfs_write+0x17f/0x4d0 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xf2/0x210 fs/read_write.c:582 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb The buggy address belongs to the object at ffff8880a6480bc0 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1504 bytes inside of 2048-byte region [ffff8880a6480bc0, ffff8880a64813c0) The buggy address belongs to the page: page:ffffea0002992000 count:1 mapcount:0 mapping:ffff8880a6480340 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff8880a6480340 0000000000000000 0000000100000003 raw: ffffea0002291ea0 ffffea00016ba220 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a6481080: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc ffff8880a6481100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880a6481180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880a6481200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a6481280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================