================================================================== BUG: KASAN: slab-out-of-bounds in fbcon_get_font+0x4a1/0x910 drivers/video/fbdev/core/fbcon.c:2491 Read of size 1 at addr ffff88804b526c10 by task syz-executor.4/4100 CPU: 0 PID: 4100 Comm: syz-executor.4 Not tainted 5.8.0-rc7-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+0x1f0/0x31e lib/dump_stack.c:118 print_address_description+0x66/0x5a0 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 fbcon_get_font+0x4a1/0x910 drivers/video/fbdev/core/fbcon.c:2491 con_font_get drivers/tty/vt/vt.c:4486 [inline] con_font_op+0x664/0x1630 drivers/tty/vt/vt.c:4645 vt_ioctl+0x24a3/0x3ec0 drivers/tty/vt/vt_ioctl.c:980 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl fs/ioctl.c:753 [inline] __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cc79 Code: 2d 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f696c1dcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000f5c0 RCX: 000000000045cc79 RDX: 0000000020000900 RSI: 0000000000004b72 RDI: 0000000000000003 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007ffc45b37d5f R14: 00007f696c1dd9c0 R15: 000000000078bf0c Allocated by task 30416: save_stack mm/kasan/common.c:48 [inline] set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x24b/0x330 mm/slab.c:3665 kmalloc include/linux/slab.h:560 [inline] fbcon_set_font+0x2c4/0x970 drivers/video/fbdev/core/fbcon.c:2673 con_font_set drivers/tty/vt/vt.c:4578 [inline] con_font_op+0xebc/0x1630 drivers/tty/vt/vt.c:4643 vt_ioctl+0x24a3/0x3ec0 drivers/tty/vt/vt_ioctl.c:980 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl fs/ioctl.c:753 [inline] __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff88804b520000 which belongs to the cache kmalloc-32k of size 32768 The buggy address is located 27664 bytes inside of 32768-byte region [ffff88804b520000, ffff88804b528000) The buggy address belongs to the page: page:ffffea00012d4800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea00012d4800 order:4 compound_mapcount:0 compound_pincount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea0001200808 ffffea0000d36008 ffff8880aa402540 raw: 0000000000000000 ffff88804b520000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88804b526b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88804b526b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88804b526c00: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88804b526c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88804b526d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================