================================================================== BUG: KASAN: slab-out-of-bounds in fbcon_get_font+0x508/0x530 drivers/video/fbdev/core/fbcon.c:2437 Read of size 1 at addr ffff8881f4a24550 by task syz-executor.2/3132 CPU: 0 PID: 3132 Comm: syz-executor.2 Not tainted 4.14.172-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+0x13e/0x194 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1e2 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+0xa9/0x2ae mm/kasan/report.c:393 fbcon_get_font+0x508/0x530 drivers/video/fbdev/core/fbcon.c:2437 con_font_get drivers/tty/vt/vt.c:4078 [inline] con_font_op+0x1c6/0xf70 drivers/tty/vt/vt.c:4229 vt_ioctl+0xaf8/0x1f00 drivers/tty/vt/vt_ioctl.c:918 tty_ioctl+0x6c5/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c479 RSP: 002b:00007f9c9b81cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9c9b81d6d4 RCX: 000000000045c479 RDX: 0000000020000380 RSI: 0000000000004b60 RDI: 0000000000000003 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000328 R14: 00000000004c54db R15: 000000000076bf2c Allocated by task 4154: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15b/0x7c0 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] fbcon_set_font+0x2f8/0x7c0 drivers/video/fbdev/core/fbcon.c:2618 con_font_set drivers/tty/vt/vt.c:4162 [inline] con_font_op+0xb73/0xf70 drivers/tty/vt/vt.c:4227 vt_ioctl+0x1334/0x1f00 drivers/tty/vt/vt_ioctl.c:970 tty_ioctl+0x6c5/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff8881f4a20340 which belongs to the cache kmalloc-32768 of size 32768 The buggy address is located 16912 bytes inside of 32768-byte region [ffff8881f4a20340, ffff8881f4a28340) The buggy address belongs to the page: page:ffffea0007d28800 count:1 mapcount:0 mapping:ffff8881f4a20340 index:0x0 compound_mapcount: 0 flags: 0x57ffe0000008100(slab|head) raw: 057ffe0000008100 ffff8881f4a20340 0000000000000000 0000000100000001 raw: ffffea0008576c20 ffffea0007726420 ffff88812fe55380 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881f4a24400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881f4a24480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8881f4a24500: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc ^ ffff8881f4a24580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881f4a24600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================