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BUG: KASAN: slab-out-of-bounds in fbcon_get_font+0x58a/0x5b0 drivers/video/fbdev/core/fbcon.c:2462
Read of size 1 at addr ffff88805f8ca350 by task syz-executor.3/31202

CPU: 0 PID: 31202 Comm: syz-executor.3 Not tainted 4.19.127-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+0x1fc/0x2fe lib/dump_stack.c:118
 print_address_description.cold+0x54/0x222 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x88/0x2b9 mm/kasan/report.c:396
 fbcon_get_font+0x58a/0x5b0 drivers/video/fbdev/core/fbcon.c:2462
 con_font_get drivers/tty/vt/vt.c:4437 [inline]
 con_font_op+0x1f7/0x1130 drivers/tty/vt/vt.c:4596
 do_fontx_ioctl drivers/tty/vt/vt_ioctl.c:273 [inline]
 vt_ioctl+0x1d25/0x2500 drivers/tty/vt/vt_ioctl.c:945
 tty_ioctl+0x7a5/0x1420 drivers/tty/tty_io.c:2669
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ca69
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:00007fe8d4f0ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e5a80 RCX: 000000000045ca69
RDX: 00000000200006c0 RSI: 0000000000004b6b RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000330 R14: 00000000004c5b95 R15: 00007fe8d4f0f6d4

Allocated by task 2140:
 __do_kmalloc mm/slab.c:3727 [inline]
 __kmalloc+0x15a/0x3c0 mm/slab.c:3736
 kmalloc include/linux/slab.h:520 [inline]
 fbcon_set_font+0x331/0x870 drivers/video/fbdev/core/fbcon.c:2644
 con_font_set drivers/tty/vt/vt.c:4529 [inline]
 con_font_op+0xd3e/0x1130 drivers/tty/vt/vt.c:4594
 vt_ioctl+0x16f1/0x2500 drivers/tty/vt/vt_ioctl.c:980
 tty_ioctl+0x7a5/0x1420 drivers/tty/tty_io.c:2669
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 32371:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xce/0x220 mm/slab.c:3822
 can_pernet_exit+0x268/0x400 net/can/af_can.c:925
 ops_exit_list.isra.0+0x9d/0x140 net/core/net_namespace.c:153
 setup_net+0x3db/0x6f0 net/core/net_namespace.c:332
 copy_net_ns+0x1f7/0x332 net/core/net_namespace.c:438
 create_new_namespaces+0x3fb/0x7c0 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:206
 ksys_unshare+0x439/0x8d0 kernel/fork.c:2530
 __do_sys_unshare kernel/fork.c:2598 [inline]
 __se_sys_unshare kernel/fork.c:2596 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:2596
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88805f8c2540
 which belongs to the cache kmalloc-32768 of size 32768
The buggy address is located 32272 bytes inside of
 32768-byte region [ffff88805f8c2540, ffff88805f8ca540)
The buggy address belongs to the page:
page:ffffea00017e3000 count:1 mapcount:0 mapping:ffff88812c3d5380 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea00019c9c08 ffffea00019a0408 ffff88812c3d5380
raw: 0000000000000000 ffff88805f8c2540 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805f8ca200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88805f8ca280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88805f8ca300: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                 ^
 ffff88805f8ca380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805f8ca400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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