================================================================== BUG: KASAN: slab-out-of-bounds in fbcon_get_font+0x1de/0x910 drivers/video/fbdev/core/fbcon.c:2496 Read of size 32 at addr ffff88804e9acc10 by task syz-executor.2/31453 CPU: 0 PID: 31453 Comm: syz-executor.2 Not tainted 5.9.0-rc2-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+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 check_memory_region_inline mm/kasan/generic.c:183 [inline] check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:192 memcpy+0x25/0x60 mm/kasan/common.c:105 fbcon_get_font+0x1de/0x910 drivers/video/fbdev/core/fbcon.c:2496 con_font_get drivers/tty/vt/vt.c:4571 [inline] con_font_op+0x664/0x1630 drivers/tty/vt/vt.c:4730 do_fontx_ioctl drivers/tty/vt/vt_ioctl.c:514 [inline] vt_io_ioctl drivers/tty/vt/vt_ioctl.c:611 [inline] vt_ioctl+0x1ac3/0x3d70 drivers/tty/vt/vt_ioctl.c:856 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f14c756bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000f1c0 RCX: 000000000045d5b9 RDX: 00000000200004c0 RSI: 0000000000004b6b RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007fffa318375f R14: 00007f14c756c9c0 R15: 000000000118cf4c Allocated by task 25807: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x218/0x320 mm/slab.c:3664 kmalloc include/linux/slab.h:559 [inline] fbcon_set_font+0x2c4/0x970 drivers/video/fbdev/core/fbcon.c:2694 con_font_set drivers/tty/vt/vt.c:4663 [inline] con_font_op+0xebc/0x1630 drivers/tty/vt/vt.c:4728 vt_io_ioctl drivers/tty/vt/vt_ioctl.c:506 [inline] vt_ioctl+0xd7f/0x3d70 drivers/tty/vt/vt_ioctl.c:856 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88804e9ac000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 3088 bytes inside of 4096-byte region [ffff88804e9ac000, ffff88804e9ad000) The buggy address belongs to the page: page:00000000597e7323 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4e9ac head:00000000597e7323 order:1 compound_mapcount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea0002466808 ffffea000284c488 ffff8880aa440900 raw: 0000000000000000 ffff88804e9ac000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88804e9acb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88804e9acb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88804e9acc00: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88804e9acc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88804e9acd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================