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BUG: KASAN: slab-out-of-bounds in vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4618
Read of size 2 at addr ffff888087c99940 by task syz-executor.0/16233

CPU: 0 PID: 16233 Comm: syz-executor.0 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:00007f4698693c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a6f9
RDX: 00000000200002c8 RSI: 00000000200002c0 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f46986946d4
R13: 00000000004cbd15 R14: 00000000004e5a80 R15: 00000000ffffffff

Allocated by task 11419:
 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+0x1fe0/0x2530 drivers/tty/vt/vt_ioctl.c:887
 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 10229:
 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
 iolatency_pd_free+0x3c/0x50 block/blk-iolatency.c:946
 blkcg_activate_policy block/blk-cgroup.c:1452 [inline]
 blkcg_activate_policy+0x3f5/0x5b0 block/blk-cgroup.c:1396
 blk_iolatency_init+0x135/0x2e0 block/blk-iolatency.c:700
 blkcg_init_queue+0x1c7/0x550 block/blk-cgroup.c:1247
 blk_alloc_queue_node+0x792/0xb90 block/blk-core.c:1085
 blk_mq_init_queue+0x4c/0xb0 block/blk-mq.c:2491
 loop_add+0x2dd/0x8d0 drivers/block/loop.c:1963
 loop_control_ioctl drivers/block/loop.c:2116 [inline]
 loop_control_ioctl+0x165/0x360 drivers/block/loop.c:2098
 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

The buggy address belongs to the object at ffff888087c99800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 320 bytes inside of
 512-byte region [ffff888087c99800, ffff888087c99a00)
The buggy address belongs to the page:
page:ffffea00021f2640 count:1 mapcount:0 mapping:ffff88812c31c940 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea0001674448 ffffea00026cf608 ffff88812c31c940
raw: 0000000000000000 ffff888087c99080 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888087c99800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888087c99880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888087c99900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
                                           ^
 ffff888087c99980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888087c99a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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