From: syzbot <syzbot+4b25dd89f2c5d49296d2@syzkaller.appspotmail.com>
To: b.zolnierkie@samsung.com, daniel.vetter@ffwll.ch,
ghalat@redhat.com, gregkh@linuxfoundation.org, jslaby@suse.com,
linux-kernel@vger.kernel.org, lukas@wunner.de,
okash.khawaja@gmail.com, sam@ravnborg.org,
syzkaller-bugs@googlegroups.com
Subject: KASAN: null-ptr-deref Read in do_con_write
Date: Thu, 13 Feb 2020 08:57:12 -0800 [thread overview]
Message-ID: <000000000000fb6fa1059e77fa6e@google.com> (raw)
Hello,
syzbot found the following crash on:
HEAD commit: f2850dd5 Merge tag 'kbuild-fixes-v5.6' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=122f97a5e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=6780df5a5f208964
dashboard link: https://syzkaller.appspot.com/bug?extid=4b25dd89f2c5d49296d2
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17b29701e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11c8fc09e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4b25dd89f2c5d49296d2@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: null-ptr-deref in scr_memcpyw include/linux/vt_buffer.h:49 [inline]
BUG: KASAN: null-ptr-deref in delete_char drivers/tty/vt/vt.c:852 [inline]
BUG: KASAN: null-ptr-deref in csi_P drivers/tty/vt/vt.c:1985 [inline]
BUG: KASAN: null-ptr-deref in do_con_trol drivers/tty/vt/vt.c:2379 [inline]
BUG: KASAN: null-ptr-deref in do_con_write+0x94d2/0xf360 drivers/tty/vt/vt.c:2797
Read of size 4294967294 at addr 0000000000000012 by task syz-executor662/8804
CPU: 0 PID: 8804 Comm: syz-executor662 Not tainted 5.6.0-rc1-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+0x1fb/0x318 lib/dump_stack.c:118
__kasan_report+0x167/0x1c0 mm/kasan/report.c:510
kasan_report+0x26/0x50 mm/kasan/common.c:641
check_memory_region_inline mm/kasan/generic.c:182 [inline]
check_memory_region+0x2b6/0x2f0 mm/kasan/generic.c:192
memcpy+0x28/0x60 mm/kasan/common.c:127
scr_memcpyw include/linux/vt_buffer.h:49 [inline]
delete_char drivers/tty/vt/vt.c:852 [inline]
csi_P drivers/tty/vt/vt.c:1985 [inline]
do_con_trol drivers/tty/vt/vt.c:2379 [inline]
do_con_write+0x94d2/0xf360 drivers/tty/vt/vt.c:2797
con_write+0x25/0x40 drivers/tty/vt/vt.c:3135
process_output_block drivers/tty/n_tty.c:595 [inline]
n_tty_write+0xd0c/0x1200 drivers/tty/n_tty.c:2333
do_tty_write drivers/tty/tty_io.c:962 [inline]
tty_write+0x5a1/0x950 drivers/tty/tty_io.c:1046
__vfs_write+0xb8/0x740 fs/read_write.c:494
vfs_write+0x270/0x580 fs/read_write.c:558
ksys_write+0x117/0x220 fs/read_write.c:611
__do_sys_write fs/read_write.c:623 [inline]
__se_sys_write fs/read_write.c:620 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:620
do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4404f9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffb1720718 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004404f9
RDX: 0000000000000078 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401de0
R13: 0000000000401e70 R14: 0000000000000000 R15: 0000000000000000
==================================================================
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
reply other threads:[~2020-02-13 16:57 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=000000000000fb6fa1059e77fa6e@google.com \
--to=syzbot+4b25dd89f2c5d49296d2@syzkaller.appspotmail.com \
--cc=b.zolnierkie@samsung.com \
--cc=daniel.vetter@ffwll.ch \
--cc=ghalat@redhat.com \
--cc=gregkh@linuxfoundation.org \
--cc=jslaby@suse.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lukas@wunner.de \
--cc=okash.khawaja@gmail.com \
--cc=sam@ravnborg.org \
--cc=syzkaller-bugs@googlegroups.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).