================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:655 [inline] BUG: KASAN: slab-out-of-bounds in fb_pad_aligned_buffer+0x52f/0x5b0 drivers/video/fbdev/core/fbmem.c:116 Read of size 1 at addr ffff88808edd1f10 by task syz-executor.3/23857 CPU: 1 PID: 23857 Comm: syz-executor.3 Not tainted 5.6.0-rc3-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+0x1fb/0x318 lib/dump_stack.c:118 print_address_description+0x74/0x5c0 mm/kasan/report.c:374 __kasan_report+0x149/0x1c0 mm/kasan/report.c:506 kasan_report+0x26/0x50 mm/kasan/common.c:641 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:132 __fb_pad_aligned_buffer include/linux/fb.h:655 [inline] fb_pad_aligned_buffer+0x52f/0x5b0 drivers/video/fbdev/core/fbmem.c:116 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:99 [inline] bit_putcs+0x1694/0x1cc0 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x7b4/0xad0 drivers/video/fbdev/core/fbcon.c:1360 do_update_region+0x462/0x600 drivers/tty/vt/vt.c:677 redraw_screen+0xcc5/0x1830 drivers/tty/vt/vt.c:1022 vc_do_resize+0x12af/0x1af0 drivers/tty/vt/vt.c:1295 vc_resize+0x4f/0x60 drivers/tty/vt/vt.c:1315 vt_ioctl+0x2f6d/0x3a30 drivers/tty/vt/vt_ioctl.c:891 tty_ioctl+0xee6/0x15c0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl fs/ioctl.c:763 [inline] __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl+0x113/0x190 fs/ioctl.c:770 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:770 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c449 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:00007f8dbb772c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f8dbb7736d4 RCX: 000000000045c449 RDX: 0000000020000080 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000066b R14: 00000000004c8fe0 R15: 000000000076bf2c Allocated by task 23589: save_stack mm/kasan/common.c:72 [inline] set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc+0x118/0x1c0 mm/kasan/common.c:515 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x254/0x340 mm/slab.c:3665 kmalloc include/linux/slab.h:560 [inline] fbcon_set_font+0x2de/0x990 drivers/video/fbdev/core/fbcon.c:2670 con_font_set drivers/tty/vt/vt.c:4549 [inline] con_font_op+0xeb9/0x1620 drivers/tty/vt/vt.c:4614 vt_ioctl+0x23b7/0x3a30 drivers/tty/vt/vt_ioctl.c:970 tty_ioctl+0xee6/0x15c0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl fs/ioctl.c:763 [inline] __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl+0x113/0x190 fs/ioctl.c:770 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:770 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 22514: save_stack mm/kasan/common.c:72 [inline] set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x12e/0x1e0 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kfree+0x10d/0x220 mm/slab.c:3757 skb_free_head net/core/skbuff.c:590 [inline] skb_release_data+0x72f/0x8c0 net/core/skbuff.c:610 skb_release_all net/core/skbuff.c:664 [inline] __kfree_skb+0x59/0x1c0 net/core/skbuff.c:678 consume_skb+0x72/0x110 net/core/skbuff.c:837 nlmon_xmit+0x91/0xc0 drivers/net/nlmon.c:14 __netdev_start_xmit include/linux/netdevice.h:4523 [inline] netdev_start_xmit include/linux/netdevice.h:4537 [inline] xmit_one net/core/dev.c:3475 [inline] dev_hard_start_xmit+0x1b1/0x3f0 net/core/dev.c:3491 __dev_queue_xmit+0x1c07/0x2930 net/core/dev.c:4050 dev_queue_xmit+0x17/0x20 net/core/dev.c:4083 __netlink_deliver_tap_skb net/netlink/af_netlink.c:294 [inline] __netlink_deliver_tap net/netlink/af_netlink.c:312 [inline] netlink_deliver_tap+0x5f6/0x860 net/netlink/af_netlink.c:325 netlink_deliver_tap_kernel net/netlink/af_netlink.c:334 [inline] netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x740/0x920 net/netlink/af_netlink.c:1329 netlink_sendmsg+0xa2b/0xd40 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] kernel_sendmsg+0x109/0x140 net/socket.c:692 sock_no_sendpage+0x100/0x140 net/core/sock.c:2740 kernel_sendpage net/socket.c:3789 [inline] sock_sendpage+0xd3/0x120 net/socket.c:950 pipe_to_sendpage+0x238/0x320 fs/splice.c:458 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x33d/0x870 fs/splice.c:636 splice_from_pipe fs/splice.c:671 [inline] generic_splice_sendpage+0x114/0x180 fs/splice.c:844 do_splice_from fs/splice.c:863 [inline] do_splice fs/splice.c:1170 [inline] __do_sys_splice fs/splice.c:1447 [inline] __se_sys_splice+0x719/0x1ac0 fs/splice.c:1427 __x64_sys_splice+0xe5/0x100 fs/splice.c:1427 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88808edd0000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 7952 bytes inside of 8192-byte region [ffff88808edd0000, ffff88808edd2000) The buggy address belongs to the page: page:ffffea00023b7400 refcount:1 mapcount:0 mapping:ffff8880aa4021c0 index:0x0 compound_mapcount: 0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea000246d308 ffffea0000f90908 ffff8880aa4021c0 raw: 0000000000000000 ffff88808edd0000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808edd1e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88808edd1e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88808edd1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88808edd1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88808edd2000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================