Hello,
syzbot found the following crash on:
HEAD commit: a844dc4c Linux 4.14.158
git tree: linux-4.14.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=141df851e00000
kernel config:
https://syzkaller.appspot.com/x/.config?x=c02bef505ffc02ff
dashboard link:
https://syzkaller.appspot.com/bug?extid=c97c8c03d2388fbba687
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by:
syzbot+c97c8c...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: global-out-of-bounds in memcpy include/linux/string.h:347
[inline]
BUG: KASAN: global-out-of-bounds in soft_cursor+0x43d/0xa50
drivers/video/fbdev/core/softcursor.c:70
Read of size 32 at addr ffffffff87065b60 by task syz-executor.3/24100
CPU: 0 PID: 24100 Comm: syz-executor.3 Not tainted 4.14.158-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+0x142/0x197 lib/dump_stack.c:58
print_address_description.cold+0x5/0x1dc 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+0xa9/0x2af mm/kasan/report.c:393
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x123/0x190 mm/kasan/kasan.c:267
memcpy+0x24/0x50 mm/kasan/kasan.c:302
memcpy include/linux/string.h:347 [inline]
soft_cursor+0x43d/0xa50 drivers/video/fbdev/core/softcursor.c:70
bit_cursor+0x11be/0x1830 drivers/video/fbdev/core/bitblit.c:386
fbcon_cursor+0x4e3/0x6f0 drivers/video/fbdev/core/fbcon.c:1347
hide_cursor+0x9d/0x2e0 drivers/tty/vt/vt.c:589
redraw_screen+0x2a5/0x7c0 drivers/tty/vt/vt.c:679
fbcon_do_set_font+0x6d1/0x9a0 drivers/video/fbdev/core/fbcon.c:2561
fbcon_copy_font+0x12c/0x190 drivers/video/fbdev/core/fbcon.c:2576
con_font_copy drivers/tty/vt/vt.c:4218 [inline]
con_font_op+0x5c6/0x1060 drivers/tty/vt/vt.c:4233
vt_ioctl+0x179f/0x2170 drivers/tty/vt/vt_ioctl.c:979
tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a909
RSP: 002b:00007f7ec5588c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a909
RDX: 0000000020000400 RSI: 0000000000004b72 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7ec55896d4
R13: 00000000004c3a41 R14: 00000000004d8f78 R15: 00000000ffffffff
The buggy address belongs to the variable:
str__msr__trace_system_name+0x200/0x9a0
Memory state around the buggy address:
ffffffff87065a00: fa fa fa fa 00 00 00 00 06 fa fa fa fa fa fa fa
ffffffff87065a80: 00 00 00 fa fa fa fa fa 00 00 00 fa fa fa fa fa
> ffffffff87065b00: 00 00 00 03 fa fa fa fa 00 00 00 04 fa fa fa fa
^
ffffffff87065b80: 00 00 00 00 03 fa fa fa fa fa fa fa 00 00 07 fa
ffffffff87065c00: fa fa fa fa 00 00 00 00 00 00 03 fa fa fa fa fa
==================================================================
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