================================================================== BUG: KASAN: slab-out-of-bounds in vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4618 Read of size 2 at addr ffff8880a4045af8 by task syz-executor.2/13252 CPU: 0 PID: 13252 Comm: syz-executor.2 Not tainted 4.19.88-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+0x197/0x210 lib/dump_stack.c:118 print_address_description.cold+0x7c/0x20d 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+0x8c/0x2ba mm/kasan/report.c:396 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:431 vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4618 vcs_write+0x646/0xcf0 drivers/tty/vt/vc_screen.c:526 __vfs_write+0x114/0x810 fs/read_write.c:485 vfs_write+0x20c/0x560 fs/read_write.c:549 ksys_write+0x14f/0x2d0 fs/read_write.c:599 __do_sys_write fs/read_write.c:611 [inline] __se_sys_write fs/read_write.c:608 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:608 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a6f9 Code: ad 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8541eb1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a6f9 RDX: 0000000000000090 RSI: 00000000200001c0 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8541eb26d4 R13: 00000000004cb4ad R14: 00000000004e4df0 R15: 00000000ffffffff Allocated by task 13153: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:531 __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15d/0x750 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] kzalloc include/linux/slab.h:709 [inline] vc_do_resize+0x262/0x14a0 drivers/tty/vt/vt.c:1190 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1307 vt_ioctl+0x146c/0x2530 drivers/tty/vt/vt_ioctl.c:840 tty_ioctl+0x7f3/0x1510 drivers/tty/tty_io.c:2669 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 12085: save_stack+0x45/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 free_bprm+0x1b6/0x220 fs/exec.c:1429 __do_execve_file.isra.0+0x19e9/0x2150 fs/exec.c:1830 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1959 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a4045a00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 248 bytes inside of 256-byte region [ffff8880a4045a00, ffff8880a4045b00) The buggy address belongs to the page: page:ffffea0002901140 count:1 mapcount:0 mapping:ffff88812c31c7c0 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea00023fbf88 ffffea0002913548 ffff88812c31c7c0 raw: 0000000000000000 ffff8880a4045000 000000010000000c 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a4045980: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a4045a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880a4045a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc ^ ffff8880a4045b00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ffff8880a4045b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================