From: syzbot <syzbot+6a35cd2d9559c909d570@syzkaller.appspotmail.com>
To: davem@davemloft.net, dvlasenk@redhat.com,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
syzkaller-bugs@googlegroups.com, xiaolou4617@gmail.com,
xiyou.wangcong@gmail.com
Subject: KASAN: null-ptr-deref Read in refcount_inc_not_zero
Date: Sun, 22 Apr 2018 18:02:02 -0700 [thread overview]
Message-ID: <000000000000eeeeff056a79954c@google.com> (raw)
Hello,
syzbot hit the following crash on upstream commit
285848b0f4074f04ab606f1e5dca296482033d54 (Sun Apr 22 04:20:48 2018 +0000)
Merge tag 'random_for_linus_stable' of
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=6a35cd2d9559c909d570
So far this crash happened 1772 times on upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5975533900791808
syzkaller reproducer:
https://syzkaller.appspot.com/x/repro.syz?id=4813418829709312
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=5008564225572864
Kernel config:
https://syzkaller.appspot.com/x/.config?id=1808800213120130118
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6a35cd2d9559c909d570@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for
details.
If you forward the report, please keep this part and the footer.
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
==================================================================
BUG: KASAN: null-ptr-deref in atomic_read
include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: null-ptr-deref in refcount_inc_not_zero+0x8f/0x2d0
lib/refcount.c:120
Read of size 4 at addr 0000000000000004 by task syzkaller633288/4488
CPU: 0 PID: 4488 Comm: syzkaller633288 Not tainted 4.17.0-rc1+ #12
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+0x1b9/0x294 lib/dump_stack.c:113
kasan_report_error mm/kasan/report.c:352 [inline]
kasan_report.cold.7+0x6d/0x2fe mm/kasan/report.c:412
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
refcount_inc_not_zero+0x8f/0x2d0 lib/refcount.c:120
refcount_inc+0x15/0x70 lib/refcount.c:153
llc_sap_hold include/net/llc.h:116 [inline]
llc_ui_release+0xba/0x2b0 net/llc/af_llc.c:207
sock_release+0x96/0x1b0 net/socket.c:594
sock_close+0x16/0x20 net/socket.c:1149
__fput+0x34d/0x890 fs/file_table.c:209
____fput+0x15/0x20 fs/file_table.c:243
task_work_run+0x1e4/0x290 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x1aee/0x2730 kernel/exit.c:865
do_group_exit+0x16f/0x430 kernel/exit.c:968
__do_sys_exit_group kernel/exit.c:979 [inline]
__se_sys_exit_group kernel/exit.c:977 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:977
do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x43e878
RSP: 002b:00007ffd854075f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043e878
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004be220 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006cc160 R14: 0000000000000000 R15: 0000000000000000
==================================================================
---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to syzkaller@googlegroups.com.
syzbot will keep track of this bug report.
If you forgot to add the Reported-by tag, once the fix for this bug is
merged
into any tree, please reply to this email with:
#syz fix: exact-commit-title
If you want to test a patch for this bug, please reply with:
#syz test: git://repo/address.git branch
and provide the patch inline or as an attachment.
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug
report.
Note: all commands must start from beginning of the line in the email body.
next reply other threads:[~2018-04-23 1:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-23 1:02 syzbot [this message]
2018-04-23 20:05 ` KASAN: null-ptr-deref Read in refcount_inc_not_zero Cong Wang
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=000000000000eeeeff056a79954c@google.com \
--to=syzbot+6a35cd2d9559c909d570@syzkaller.appspotmail.com \
--cc=davem@davemloft.net \
--cc=dvlasenk@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=syzkaller-bugs@googlegroups.com \
--cc=xiaolou4617@gmail.com \
--cc=xiyou.wangcong@gmail.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.