audit: type=1804 audit(1621684607.843:235): pid=19433 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.4" name="/root/syzkaller-testdir891291673/syzkaller.Sp9fI0/158/file1/bus" dev="loop4" ino=35 res=1 ================================================================== BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:377 [inline] BUG: KASAN: slab-out-of-bounds in soft_cursor+0x44b/0xa30 drivers/video/fbdev/core/softcursor.c:70 Read of size 7 at addr ffff8880935fdfee by task syz-executor.0/19430 CPU: 0 PID: 19430 Comm: syz-executor.0 Not tainted 4.19.191-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+0x8f/0xa0 mm/kasan/report.c:412 memcpy+0x20/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:377 [inline] soft_cursor+0x44b/0xa30 drivers/video/fbdev/core/softcursor.c:70 bit_cursor+0x1126/0x1740 drivers/video/fbdev/core/bitblit.c:377 fbcon_cursor+0x531/0x710 drivers/video/fbdev/core/fbcon.c:1312 hide_cursor+0x85/0x2c0 drivers/tty/vt/vt.c:902 update_region+0x136/0x190 drivers/tty/vt/vt.c:700 vcs_write+0x403/0xc30 drivers/tty/vt/vc_screen.c:604 __vfs_write+0xf7/0x770 fs/read_write.c:485 vfs_write+0x1f3/0x540 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 RIP: 0033:0x4665d9 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:00007f8ddee49188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000000001006 RSI: 0000000020001040 RDI: 0000000000000004 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffcc50d8c7f R14: 00007f8ddee49300 R15: 0000000000022000 Allocated by task 12271: __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15a/0x3c0 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] fbcon_set_font+0x34f/0x8a0 drivers/video/fbdev/core/fbcon.c:2482 con_font_set drivers/tty/vt/vt.c:4538 [inline] con_font_op+0x94b/0xf20 drivers/tty/vt/vt.c:4582 vt_ioctl+0x1543/0x2380 drivers/tty/vt/vt_ioctl.c:990 tty_ioctl+0x5b0/0x15c0 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcdb/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 Freed by task 11470: __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 net/core/skbuff.c:654 [inline] consume_skb+0x113/0x3d0 net/core/skbuff.c:714 skb_free_datagram+0x16/0xf0 net/core/datagram.c:329 netlink_recvmsg+0x627/0xea0 net/netlink/af_netlink.c:1988 sock_recvmsg_nosec net/socket.c:795 [inline] sock_recvmsg net/socket.c:802 [inline] sock_recvmsg+0xca/0x110 net/socket.c:798 ___sys_recvmsg+0x255/0x570 net/socket.c:2277 __sys_recvmsg net/socket.c:2326 [inline] __do_sys_recvmsg net/socket.c:2336 [inline] __se_sys_recvmsg net/socket.c:2333 [inline] __x64_sys_recvmsg+0x12f/0x220 net/socket.c:2333 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 ffff8880935fdb00 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 238 bytes to the right of 1024-byte region [ffff8880935fdb00, ffff8880935fdf00) The buggy address belongs to the page: page:ffffea00024d7f00 count:1 mapcount:0 mapping:ffff88813bff0ac0 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea0002ceec88 ffffea0002464588 ffff88813bff0ac0 raw: 0000000000000000 ffff8880935fc000 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880935fde80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880935fdf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880935fdf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880935fe000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880935fe080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================