================================================================== BUG: KASAN: slab-out-of-bounds in vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4618 Read of size 2 at addr ffff88808f8ff0e0 by task syz-executor.2/24894 CPU: 1 PID: 24894 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: 0033:0x45a909 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:00007f209dda8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a909 RDX: 00000001000001bd RSI: 0000000020002300 RDI: 0000000000000004 RBP: 000000000075c268 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f209dda96d4 R13: 00000000004cbdc5 R14: 00000000004e5a58 R15: 00000000ffffffff Allocated by task 16487: 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 0: (stack is not available) The buggy address belongs to the object at ffff88808f8fec80 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1120 bytes inside of 2048-byte region [ffff88808f8fec80, ffff88808f8ff480) The buggy address belongs to the page: page:ffffea00023e3f80 count:1 mapcount:0 mapping:ffff88812c31cc40 index:0xffff88808f8fe400 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffffea0002516a08 ffffea00013ee988 ffff88812c31cc40 raw: ffff88808f8fe400 ffff88808f8fe400 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808f8fef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88808f8ff000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88808f8ff080: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ^ ffff88808f8ff100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88808f8ff180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== kobject: 'loop1' (0000000058b869b6): kobject_uevent_env kobject: 'loop1' (0000000058b869b6): fill_kobj_path: path = '/devices/virtual/block/loop1'