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BUG: KASAN: use-after-free in memcpy include/linux/string.h:406 [inline]
BUG: KASAN: use-after-free in scr_memcpyw include/linux/vt_buffer.h:49 [inline]
BUG: KASAN: use-after-free in vc_do_resize+0x9d3/0x13f0 drivers/tty/vt/vt.c:1280
Read of size 2 at addr ffff888092d5c3c0 by task syz-executor.3/24964

CPU: 0 PID: 24964 Comm: syz-executor.3 Not tainted 5.8.0-rc2-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 check_memory_region_inline mm/kasan/generic.c:186 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
 memcpy+0x20/0x60 mm/kasan/common.c:105
 memcpy include/linux/string.h:406 [inline]
 scr_memcpyw include/linux/vt_buffer.h:49 [inline]
 vc_do_resize+0x9d3/0x13f0 drivers/tty/vt/vt.c:1280
 fbcon_modechanged+0x36c/0x710 drivers/video/fbdev/core/fbcon.c:2990
 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:3048
 fb_set_var+0xae8/0xd60 drivers/video/fbdev/core/fbmem.c:1056
 do_fb_ioctl+0x33f/0x6c0 drivers/video/fbdev/core/fbmem.c:1109
 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:753
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl fs/ioctl.c:760 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb19
Code: Bad RIP value.
RSP: 002b:00007f55ea2c0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e5500 RCX: 000000000045cb19
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000002fc R14: 00000000004c587a R15: 00007f55ea2c16d4

Allocated by task 2499:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 kmem_cache_alloc_trace+0x14f/0x2d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 __hw_addr_create_ex+0x5b/0x310 net/core/dev_addr_lists.c:30
 __hw_addr_add_ex+0x1ed/0x2b0 net/core/dev_addr_lists.c:76
 __dev_mc_add net/core/dev_addr_lists.c:766 [inline]
 dev_mc_add+0x6c/0xb0 net/core/dev_addr_lists.c:783
 igmp6_group_added+0x4bc/0x5d0 net/ipv6/mcast.c:669
 __ipv6_dev_mc_inc+0x811/0xca0 net/ipv6/mcast.c:928
 addrconf_join_solict net/ipv6/addrconf.c:2142 [inline]
 addrconf_join_solict net/ipv6/addrconf.c:2134 [inline]
 addrconf_dad_begin net/ipv6/addrconf.c:3908 [inline]
 addrconf_dad_work+0xc92/0x1280 net/ipv6/addrconf.c:4035
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Freed by task 3837:
 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+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free_bulk+0x7f/0x290 mm/slab.c:3721
 kfree_bulk include/linux/slab.h:412 [inline]
 kfree_rcu_work+0x1a1/0x470 kernel/rcu/tree.c:3051
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff888092d5c380
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 64 bytes inside of
 96-byte region [ffff888092d5c380, ffff888092d5c3e0)
The buggy address belongs to the page:
page:ffffea00024b5700 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888092d5cc80
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffff8880aa001440 ffffea00025fdd48 ffff8880aa000540
raw: ffff888092d5cc80 ffff888092d5c000 000000010000001e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888092d5c280: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
 ffff888092d5c300: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
>ffff888092d5c380: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                                           ^
 ffff888092d5c400: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
 ffff888092d5c480: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
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