================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:348 [inline] BUG: KASAN: use-after-free in soft_cursor+0x448/0xa20 drivers/video/fbdev/core/softcursor.c:70 Read of size 32 at addr ffff88809b03ee50 by task syz-executor.0/14840 CPU: 0 PID: 14840 Comm: syz-executor.0 Not tainted 4.19.109-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+0x188/0x20d lib/dump_stack.c:118 print_address_description.cold+0x7c/0x212 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+0x88/0x2b9 mm/kasan/report.c:396 memcpy+0x20/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:348 [inline] soft_cursor+0x448/0xa20 drivers/video/fbdev/core/softcursor.c:70 bit_cursor+0x1230/0x1900 drivers/video/fbdev/core/bitblit.c:386 fbcon_cursor+0x572/0x760 drivers/video/fbdev/core/fbcon.c:1369 hide_cursor+0x99/0x2f0 drivers/tty/vt/vt.c:895 redraw_screen+0x2ed/0x870 drivers/tty/vt/vt.c:999 vc_do_resize+0x109e/0x13a0 drivers/tty/vt/vt.c:1298 vt_ioctl+0x1dff/0x2310 drivers/tty/vt/vt_ioctl.c:891 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcda/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 RIP: 0033:0x45c849 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:00007f9db0a09c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9db0a0a6d4 RCX: 000000000045c849 RDX: 0000000020000000 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000066b R14: 00000000004c93fd R15: 000000000076bf0c Allocated by task 7473: set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531 kmem_cache_alloc_trace+0x14d/0x7a0 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] kernfs_fop_open+0x2b3/0xdb0 fs/kernfs/file.c:648 do_dentry_open+0x4a8/0x1160 fs/open.c:796 do_last fs/namei.c:3421 [inline] path_openat+0x1031/0x4200 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3c0/0x500 fs/open.c:1088 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7473: set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/kasan.c:521 __cache_free mm/slab.c:3503 [inline] kfree+0xce/0x220 mm/slab.c:3822 kernfs_fop_release+0x124/0x190 fs/kernfs/file.c:783 __fput+0x2cd/0x890 fs/file_table.c:278 task_work_run+0x13f/0x1b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x25a/0x2b0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809b03ecc0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 400 bytes inside of 512-byte region [ffff88809b03ecc0, ffff88809b03eec0) The buggy address belongs to the page: page:ffffea00026c0f80 count:1 mapcount:0 mapping:ffff88812c3dc940 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea00016d1088 ffffea00020e5bc8 ffff88812c3dc940 raw: 0000000000000000 ffff88809b03e040 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809b03ed00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809b03ed80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88809b03ee00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809b03ee80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88809b03ef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================