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BUG: KASAN: use-after-free in __fb_pad_aligned_buffer include/linux/fb.h:655 [inline]
BUG: KASAN: use-after-free in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
BUG: KASAN: use-after-free in bit_putcs+0xc08/0xd60 drivers/video/fbdev/core/bitblit.c:185
Read of size 1 at addr ffff88809e40f008 by task syz-executor.0/21531

CPU: 0 PID: 21531 Comm: syz-executor.0 Not tainted 5.7.0-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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 __fb_pad_aligned_buffer include/linux/fb.h:655 [inline]
 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
 bit_putcs+0xc08/0xd60 drivers/video/fbdev/core/bitblit.c:185
 fbcon_putcs+0x345/0x3f0 drivers/video/fbdev/core/fbcon.c:1362
 do_update_region+0x398/0x630 drivers/tty/vt/vt.c:683
 redraw_screen+0x64c/0x770 drivers/tty/vt/vt.c:1029
 vc_do_resize+0x1007/0x1370 drivers/tty/vt/vt.c:1314
 vt_ioctl+0x200c/0x2640 drivers/tty/vt/vt_ioctl.c:901
 tty_ioctl+0xedc/0x1440 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:771
 __do_sys_ioctl fs/ioctl.c:780 [inline]
 __se_sys_ioctl fs/ioctl.c:778 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:778
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca59
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:00007f6978571c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004f3060 RCX: 000000000045ca59
RDX: 0000000020000040 RSI: 000000000000560a RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000067a R14: 00000000004c973d R15: 00007f69785726d4

Allocated by task 21048:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc mm/kasan/common.c:494 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467
 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 call_usermodehelper_setup+0x98/0x300 kernel/umh.c:386
 kobject_uevent_env+0xd9c/0x12e0 lib/kobject_uevent.c:613
 netdev_queue_add_kobject net/core/net-sysfs.c:1554 [inline]
 netdev_queue_update_kobjects+0x2ee/0x3c0 net/core/net-sysfs.c:1588
 register_queue_kobjects net/core/net-sysfs.c:1649 [inline]
 netdev_register_kobject+0x297/0x3b0 net/core/net-sysfs.c:1892
 register_netdevice+0xa80/0x10b0 net/core/dev.c:9510
 register_netdev+0x2d/0x50 net/core/dev.c:9634
 loopback_net_init+0x73/0x160 drivers/net/loopback.c:216
 ops_init+0xaf/0x420 net/core/net_namespace.c:151
 setup_net+0x2de/0x860 net/core/net_namespace.c:341
 copy_net_ns+0x293/0x590 net/core/net_namespace.c:482
 create_new_namespaces+0x3fb/0xb30 kernel/nsproxy.c:110
 copy_namespaces+0x385/0x470 kernel/nsproxy.c:179
 copy_process+0x2a4a/0x7130 kernel/fork.c:2102
 _do_fork+0x12d/0x1010 kernel/fork.c:2444
 __do_sys_clone+0xef/0x150 kernel/fork.c:2600
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 21051:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 call_usermodehelper_freeinfo kernel/umh.c:48 [inline]
 umh_complete kernel/umh.c:62 [inline]
 umh_complete+0x81/0x90 kernel/umh.c:51
 call_usermodehelper_exec_async+0x45f/0x710 kernel/umh.c:122
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351

The buggy address belongs to the object at ffff88809e40f000
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 8 bytes inside of
 192-byte region [ffff88809e40f000, ffff88809e40f0c0)
The buggy address belongs to the page:
page:ffffea00027903c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809e40fe00
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00025b5b48 ffffea00027af148 ffff8880aa000000
raw: ffff88809e40fe00 ffff88809e40f000 000000010000000d 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809e40ef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809e40ef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809e40f000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88809e40f080: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88809e40f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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