================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:348 [inline] BUG: KASAN: use-after-free in soft_cursor+0x439/0xa30 drivers/video/fbdev/core/softcursor.c:70 Read of size 16 at addr ffff8880a3c0da00 by task syz-executor.1/32152 CPU: 1 PID: 32152 Comm: syz-executor.1 Not tainted 4.19.98-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+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d 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+0x8c/0x2ba mm/kasan/report.c:396 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x123/0x190 mm/kasan/kasan.c:267 memcpy+0x24/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:348 [inline] soft_cursor+0x439/0xa30 drivers/video/fbdev/core/softcursor.c:70 bit_cursor+0x12fc/0x1a60 drivers/video/fbdev/core/bitblit.c:386 fbcon_cursor+0x58a/0x7b0 drivers/video/fbdev/core/fbcon.c:1369 hide_cursor+0x9e/0x300 drivers/tty/vt/vt.c:895 redraw_screen+0x2ee/0x8e0 drivers/tty/vt/vt.c:988 fbcon_do_set_font+0x73a/0xa40 drivers/video/fbdev/core/fbcon.c:2583 fbcon_copy_font+0x12c/0x190 drivers/video/fbdev/core/fbcon.c:2598 con_font_copy drivers/tty/vt/vt.c:4548 [inline] con_font_op+0x69a/0x1250 drivers/tty/vt/vt.c:4563 vt_ioctl+0x1784/0x2530 drivers/tty/vt/vt_ioctl.c:965 tty_ioctl+0x7f3/0x1510 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b349 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:00007f4d74833c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4d748346d4 RCX: 000000000045b349 RDX: 0000000020000080 RSI: 0000000000004b72 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000367 R14: 00000000004c4882 R15: 000000000075bf2c Allocated by task 24955: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 kmem_cache_alloc_trace+0x152/0x760 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] sctp_endpoint_new+0x79/0xd70 net/sctp/endpointola.c:192 sctp_init_sock+0xb87/0x1290 net/sctp/socket.c:4747 inet_create net/ipv4/af_inet.c:379 [inline] inet_create+0x864/0xdf0 net/ipv4/af_inet.c:247 __sock_create+0x3d8/0x730 net/socket.c:1276 sock_create net/socket.c:1316 [inline] __sys_socket+0x103/0x220 net/socket.c:1346 __do_sys_socket net/socket.c:1355 [inline] __se_sys_socket net/socket.c:1353 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1353 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 24955: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 sctp_endpoint_destroy net/sctp/endpointola.c:282 [inline] sctp_endpoint_put+0x239/0x2c0 net/sctp/endpointola.c:298 sctp_endpoint_free+0x77/0x90 net/sctp/endpointola.c:241 sctp_destroy_sock+0x9f/0x3e0 net/sctp/socket.c:4800 sk_common_release+0x6b/0x330 net/core/sock.c:3067 sctp_close+0x4e4/0x860 net/sctp/socket.c:1567 inet_release+0xff/0x1e0 net/ipv4/af_inet.c:428 __sock_release+0xce/0x2a0 net/socket.c:579 sock_close+0x1b/0x30 net/socket.c:1140 __fput+0x2dd/0x8b0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xc1f/0x30d0 kernel/exit.c:880 do_group_exit+0x135/0x370 kernel/exit.c:983 get_signal+0x3ec/0x1fc0 kernel/signal.c:2578 do_signal+0x95/0x1960 arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x53d/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a3c0da00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 0 bytes inside of 512-byte region [ffff8880a3c0da00, ffff8880a3c0dc00) The buggy address belongs to the page: page:ffffea00028f0340 count:1 mapcount:0 mapping:ffff88812c31c940 index:0xffff8880a3c0d500 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea000214f508 ffffea000249ba08 ffff88812c31c940 raw: ffff8880a3c0d500 ffff8880a3c0d000 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a3c0d900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a3c0d980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880a3c0da00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a3c0da80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a3c0db00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================