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BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:663 [inline]
BUG: KASAN: slab-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
BUG: KASAN: slab-out-of-bounds in bit_putcs+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185
Read of size 1 at addr ffff8880a9b70446 by task syz-executor.2/21317

CPU: 0 PID: 21317 Comm: syz-executor.2 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393
 __fb_pad_aligned_buffer include/linux/fb.h:663 [inline]
 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
 bit_putcs+0xa8a/0xc00 drivers/video/fbdev/core/bitblit.c:185
 fbcon_putcs+0x3bb/0x480 drivers/video/fbdev/core/fbcon.c:1301
 con_flush drivers/tty/vt/vt.c:2199 [inline]
 do_con_write.part.0+0xc27/0x1a20 drivers/tty/vt/vt.c:2446
 do_con_write drivers/tty/vt/vt.c:2218 [inline]
 con_write+0x33/0xc0 drivers/tty/vt/vt.c:2798
 process_output_block drivers/tty/n_tty.c:595 [inline]
 n_tty_write+0x375/0xe20 drivers/tty/n_tty.c:2333
 do_tty_write drivers/tty/tty_io.c:959 [inline]
 tty_write+0x3f1/0x6e0 drivers/tty/tty_io.c:1043
 __vfs_write+0xe4/0x630 fs/read_write.c:480
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45cb09
RSP: 002b:00007f65b9d1ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050dd00 RCX: 000000000045cb09
RDX: 0000000000001006 RSI: 0000000020001440 RDI: 0000000000000006
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000d1d R14: 00000000004cf765 R15: 00007f65b9d1f6d4

Allocated by task 20286:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 fbcon_set_font+0x2f8/0x7c0 drivers/video/fbdev/core/fbcon.c:2621
 con_font_set drivers/tty/vt/vt.c:4182 [inline]
 con_font_op+0xb73/0xf70 drivers/tty/vt/vt.c:4247
 vt_ioctl+0x736/0x1f20 drivers/tty/vt/vt_ioctl.c:928
 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 19389:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 skb_free_head+0x83/0xa0 net/core/skbuff.c:554
 skb_release_data+0x57e/0x7d0 net/core/skbuff.c:574
 skb_release_all+0x46/0x60 net/core/skbuff.c:631
 __kfree_skb net/core/skbuff.c:645 [inline]
 kfree_skb+0xae/0x340 net/core/skbuff.c:663
 skb_queue_purge+0x14/0x30 net/core/skbuff.c:2855
 netlink_sock_destruct+0xf6/0x250 net/netlink/af_netlink.c:371
 __sk_destruct+0x49/0x640 net/core/sock.c:1556
 sk_destruct+0x97/0xc0 net/core/sock.c:1596
 __sk_free+0x4c/0x220 net/core/sock.c:1604
 sk_free+0x2b/0x40 net/core/sock.c:1615
 deferred_put_nlk_sk+0xed/0x260 net/netlink/af_netlink.c:711
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2699 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline]
 rcu_process_callbacks+0x78d/0x1180 kernel/rcu/tree.c:2946
 __do_softirq+0x254/0x9bf kernel/softirq.c:288

The buggy address belongs to the object at ffff8880a9b70300
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 326 bytes inside of
 512-byte region [ffff8880a9b70300, ffff8880a9b70500)
The buggy address belongs to the page:
page:ffffea0002a6dc00 count:1 mapcount:0 mapping:ffff8880a9b70080 index:0xffff8880a9b70080
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff8880a9b70080 ffff8880a9b70080 0000000100000005
raw: ffffea000283ece0 ffffea000280f3a0 ffff8880aa800940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a9b70300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a9b70380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a9b70400: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                           ^
 ffff8880a9b70480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a9b70500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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