overlayfs: unrecognized mount option "loweŸaó‘´‘us" or missing value ================================================================== BUG: KASAN: use-after-free in fbcon_cursor+0x5c5/0x760 drivers/video/fbdev/core/fbcon.c:1350 Read of size 2 at addr ffff888088cbb130 by task syz-executor.2/20873 CPU: 1 PID: 20873 Comm: syz-executor.2 Not tainted 4.19.125-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+0x1fc/0x2fe lib/dump_stack.c:118 print_address_description.cold+0x54/0x222 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 fbcon_cursor+0x5c5/0x760 drivers/video/fbdev/core/fbcon.c:1350 fbcon_scrolldelta+0x39c/0x12d0 drivers/video/fbdev/core/fbcon.c:2858 fbcon_set_origin+0x3c/0x50 drivers/video/fbdev/core/fbcon.c:2909 set_origin+0x32e/0x430 drivers/tty/vt/vt.c:926 vc_do_resize+0x9dc/0x1380 drivers/tty/vt/vt.c:1297 fbcon_modechanged+0x392/0x870 drivers/video/fbdev/core/fbcon.c:2961 fbcon_event_notify+0x1b2/0x1d60 drivers/video/fbdev/core/fbcon.c:3347 notifier_call_chain+0xc0/0x230 kernel/notifier.c:93 __blocking_notifier_call_chain kernel/notifier.c:317 [inline] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] blocking_notifier_call_chain kernel/notifier.c:328 [inline] blocking_notifier_call_chain+0x85/0xa0 kernel/notifier.c:325 fb_set_var+0xc39/0xe00 drivers/video/fbdev/core/fbmem.c:1042 do_fb_ioctl+0x450/0x9c0 drivers/video/fbdev/core/fbmem.c:1115 fb_ioctl+0xda/0x120 drivers/video/fbdev/core/fbmem.c:1230 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: 0033:0x45ca69 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f2d1293ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e4b00 RCX: 000000000045ca69 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002f2 R14: 00000000004c5708 R15: 00007f2d1293b6d4 Allocated by task 7365: __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15a/0x3c0 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] kzalloc include/linux/slab.h:709 [inline] vc_do_resize+0x245/0x1380 drivers/tty/vt/vt.c:1220 vt_ioctl+0x10c1/0x2500 drivers/tty/vt/vt_ioctl.c:850 tty_ioctl+0x7a5/0x1420 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 Freed by task 20873: __cache_free mm/slab.c:3503 [inline] kfree+0xce/0x220 mm/slab.c:3822 vc_do_resize+0x97c/0x1380 drivers/tty/vt/vt.c:1294 fbcon_modechanged+0x392/0x870 drivers/video/fbdev/core/fbcon.c:2961 fbcon_event_notify+0x1b2/0x1d60 drivers/video/fbdev/core/fbcon.c:3347 notifier_call_chain+0xc0/0x230 kernel/notifier.c:93 __blocking_notifier_call_chain kernel/notifier.c:317 [inline] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] blocking_notifier_call_chain kernel/notifier.c:328 [inline] blocking_notifier_call_chain+0x85/0xa0 kernel/notifier.c:325 fb_set_var+0xc39/0xe00 drivers/video/fbdev/core/fbmem.c:1042 do_fb_ioctl+0x450/0x9c0 drivers/video/fbdev/core/fbmem.c:1115 fb_ioctl+0xda/0x120 drivers/video/fbdev/core/fbmem.c:1230 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 The buggy address belongs to the object at ffff888088cbb0c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 112 bytes inside of 512-byte region [ffff888088cbb0c0, ffff888088cbb2c0) The buggy address belongs to the page: page:ffffea0002232ec0 count:1 mapcount:0 mapping:ffff88812c3dc940 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea0002797d88 ffffea0002780a08 ffff88812c3dc940 raw: 0000000000000000 ffff888088cbb0c0 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888088cbb000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888088cbb080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff888088cbb100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888088cbb180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888088cbb200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================