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BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:654 [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+0xbb6/0xd20 drivers/video/fbdev/core/bitblit.c:185
Read of size 1 at addr ffff888099090a70 by task syz-executor.1/2489

CPU: 1 PID: 2489 Comm: syz-executor.1 Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 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:654 [inline]
 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline]
 bit_putcs+0xbb6/0xd20 drivers/video/fbdev/core/bitblit.c:185
 fbcon_putcs+0x33c/0x3f0 drivers/video/fbdev/core/fbcon.c:1362
 do_update_region+0x399/0x630 drivers/tty/vt/vt.c:675
 redraw_screen+0x64e/0x770 drivers/tty/vt/vt.c:1034
 fbcon_do_set_font+0x7ec/0x950 drivers/video/fbdev/core/fbcon.c:2615
 fbcon_copy_font+0x125/0x190 drivers/video/fbdev/core/fbcon.c:2630
 con_font_copy drivers/tty/vt/vt.c:4718 [inline]
 con_font_op+0x65a/0x1110 drivers/tty/vt/vt.c:4733
 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:473 [inline]
 vt_ioctl+0x20b9/0x2c20 drivers/tty/vt/vt_ioctl.c:842
 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d239
Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff886007c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000018500 RCX: 000000000045d239
RDX: 0000000020000040 RSI: 0000000000004b72 RDI: 0000000000000003
RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffe301b161f R14: 00007ff8860089c0 R15: 000000000118cf4c

Allocated by task 6850:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 __do_kmalloc mm/slab.c:3655 [inline]
 __kmalloc_track_caller+0x1a6/0x310 mm/slab.c:3670
 kmemdup+0x23/0x50 mm/util.c:127
 kmemdup include/linux/string.h:479 [inline]
 ipv6_sysctl_net_init+0x2c/0x2a0 net/ipv6/sysctl_net_ipv6.c:208
 ops_init+0xaf/0x470 net/core/net_namespace.c:151
 setup_net+0x2d8/0x850 net/core/net_namespace.c:341
 copy_net_ns+0x2cf/0x5e0 net/core/net_namespace.c:482
 create_new_namespaces+0x3f6/0xb10 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
 ksys_unshare+0x445/0x8e0 kernel/fork.c:2921
 __do_sys_unshare kernel/fork.c:2989 [inline]
 __se_sys_unshare kernel/fork.c:2987 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:2987
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888099090000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 624 bytes to the right of
 2048-byte region [ffff888099090000, ffff888099090800)
The buggy address belongs to the page:
page:000000009548473a refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x99090
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002874a88 ffffea000247b5c8 ffff8880aa040800
raw: 0000000000000000 ffff888099090000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888099090900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888099090980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888099090a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                             ^
 ffff888099090a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888099090b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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