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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+0x132a/0x1bf0 drivers/video/fbdev/core/bitblit.c:185
Read of size 1 at addr ffff888053f50800 by task syz-executor.4/11524

CPU: 0 PID: 11524 Comm: syz-executor.4 Not tainted 5.8.0-rc4-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+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 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+0x132a/0x1bf0 drivers/video/fbdev/core/bitblit.c:185
 fbcon_putcs+0x790/0xaf0 drivers/video/fbdev/core/fbcon.c:1362
 do_update_region+0x462/0x620 drivers/tty/vt/vt.c:683
 redraw_screen+0xc30/0x16f0 drivers/tty/vt/vt.c:1029
 vc_do_resize+0x1541/0x1ce0 drivers/tty/vt/vt.c:1314
 vt_ioctl+0x3185/0x3ec0 drivers/tty/vt/vt_ioctl.c:901
 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f0126aedc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004f3d40 RCX: 000000000045cba9
RDX: 0000000020000080 RSI: 000000000000560a RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000681 R14: 00000000004c9900 R15: 00007f0126aee6d4

Allocated by task 10247:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 kmem_cache_alloc_trace+0x234/0x300 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 ipv6_add_dev+0xcd/0xf20 net/ipv6/addrconf.c:374
 addrconf_notify+0x5fb/0x3a60 net/ipv6/addrconf.c:3462
 notifier_call_chain kernel/notifier.c:83 [inline]
 __raw_notifier_call_chain kernel/notifier.c:361 [inline]
 raw_notifier_call_chain+0xe7/0x170 kernel/notifier.c:368
 call_netdevice_notifiers_info net/core/dev.c:2027 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2039 [inline]
 call_netdevice_notifiers net/core/dev.c:2053 [inline]
 register_netdevice+0x1593/0x1b80 net/core/dev.c:9545
 __ip_tunnel_create+0x235/0x2e0 net/ipv4/ip_tunnel.c:267
 ip_tunnel_init_net+0x1ad/0x600 net/ipv4/ip_tunnel.c:1072
 ops_init+0x320/0x410 net/core/net_namespace.c:151
 setup_net+0x1cb/0x770 net/core/net_namespace.c:341
 copy_net_ns+0x339/0x540 net/core/net_namespace.c:482
 create_new_namespaces+0x52e/0x9f0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x123/0x190 kernel/nsproxy.c:231
 ksys_unshare+0x463/0x950 kernel/fork.c:2983
 __do_sys_unshare kernel/fork.c:3051 [inline]
 __se_sys_unshare kernel/fork.c:3049 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3049
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 16:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 rcu_do_batch kernel/rcu/tree.c:2414 [inline]
 rcu_core+0x816/0x1120 kernel/rcu/tree.c:2641
 __do_softirq+0x268/0x80c kernel/softirq.c:292

The buggy address belongs to the object at ffff888053f50800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of
 1024-byte region [ffff888053f50800, ffff888053f50c00)
The buggy address belongs to the page:
page:ffffea00014fd400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888053f50800
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002648308 ffffea00029aee48 ffff8880aa400c40
raw: ffff888053f50800 ffff888053f50000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888053f50700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888053f50780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888053f50800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888053f50880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888053f50900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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