================================================================== BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:347 [inline] BUG: KASAN: slab-out-of-bounds in soft_cursor+0x43d/0xa50 drivers/video/fbdev/core/softcursor.c:70 Read of size 16 at addr ffff888093aa1f50 by task syz-executor.3/12595 CPU: 1 PID: 12595 Comm: syz-executor.3 Not tainted 4.14.169-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+0x142/0x197 lib/dump_stack.c:58 print_address_description.cold+0x7c/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+0xa9/0x2af mm/kasan/report.c:393 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:347 [inline] soft_cursor+0x43d/0xa50 drivers/video/fbdev/core/softcursor.c:70 bit_cursor+0x11be/0x1830 drivers/video/fbdev/core/bitblit.c:386 fbcon_cursor+0x4e3/0x6f0 drivers/video/fbdev/core/fbcon.c:1347 hide_cursor+0x9d/0x2e0 drivers/tty/vt/vt.c:589 redraw_screen+0x2a5/0x7c0 drivers/tty/vt/vt.c:679 vc_do_resize+0xc8a/0xec0 drivers/tty/vt/vt.c:954 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:974 vt_ioctl+0x10a8/0x2170 drivers/tty/vt/vt_ioctl.c:901 tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45b399 RSP: 002b:00007ff90b741c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ff90b7426d4 RCX: 000000000045b399 RDX: 0000000020000000 RSI: 000000000000560a RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000666 R14: 00000000004c7f04 R15: 000000000075bf2c Allocated by task 3598: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15d/0x7a0 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] fbcon_set_font+0x2f8/0x7b0 drivers/video/fbdev/core/fbcon.c:2618 con_font_set drivers/tty/vt/vt.c:4162 [inline] con_font_op+0xc0f/0x1060 drivers/tty/vt/vt.c:4227 vt_ioctl+0xb80/0x2170 drivers/tty/vt/vt_ioctl.c:927 tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 3717: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 kernfs_fop_release+0x112/0x180 fs/kernfs/file.c:783 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff888093aa1d40 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 16 bytes to the right of 512-byte region [ffff888093aa1d40, ffff888093aa1f40) The buggy address belongs to the page: page:ffffea00024ea840 count:1 mapcount:0 mapping:ffff888093aa10c0 index:0xffff888093aa10c0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff888093aa10c0 ffff888093aa10c0 0000000100000005 raw: ffffea0001951360 ffffea00019076a0 ffff8880aa800940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888093aa1e00: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc ffff888093aa1e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888093aa1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff888093aa1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888093aa2000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================