From: Linus Torvalds <torvalds@linux-foundation.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: kernel test robot <lkp@intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
Shuah Khan <shuah@kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Changbin Du <changbin.du@gmail.com>, Jann Horn <jannh@google.com>,
Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@kernel.org>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Nadav Amit <namit@vmware.com>,
Peter Zijlstra <peterz@infradead.org>,
Joel Fernandes <joel@joelfernandes.org>,
yhs@fb.com, lkp@01.org
Subject: Re: [uaccess] 780464aed0: WARNING:at_arch/x86/include/asm/uaccess.h:#strnlen_user/0x
Date: Sun, 3 Mar 2019 18:37:59 -0800 [thread overview]
Message-ID: <CAHk-=whYMvevgF4yh7uhQug=Wt1A1Eg7abyM=RCi=bQiqiMBvQ@mail.gmail.com> (raw)
In-Reply-To: <20190304101434.8429ffffb17813c0e7930130@kernel.org>
On Sun, Mar 3, 2019 at 5:14 PM Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> I think it comes from WARN_ON_ONCE(!segment_eq(get_fs(), USER_DS)) in
> user_access_ok(). The call trace shows that strndup_user might be called
> from kernel daemon context.
Ahh, yes.
We've had this before. We've gotten rid of the actual "use system
calls", but we still have some of the init sequence in particular just
calling the wrappers instead.
And yes, ksys_mount() takes __user pointers.
It would be a lot better to use "do_mount()", which is the interface
that takes actual "char *" pointers.
Linus
next prev parent reply other threads:[~2019-03-04 2:38 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 16:02 [PATCH v5 0/6] tracing/probes: uaccess: Add support user-space access Masami Hiramatsu
2019-02-28 16:02 ` [PATCH v5 1/6] uaccess: Add user_access_ok() Masami Hiramatsu
2019-02-28 16:03 ` [PATCH v5 2/6] uaccess: Use user_access_ok() in user_access_begin() Masami Hiramatsu
2019-03-03 17:39 ` [uaccess] 780464aed0: WARNING:at_arch/x86/include/asm/uaccess.h:#strnlen_user/0x kernel test robot
2019-03-03 19:53 ` Linus Torvalds
2019-03-04 1:14 ` Masami Hiramatsu
2019-03-04 2:37 ` Linus Torvalds [this message]
2019-03-04 9:06 ` Masami Hiramatsu
2019-03-04 15:16 ` Masami Hiramatsu
2019-03-04 15:58 ` Jann Horn
2019-03-04 18:59 ` Linus Torvalds
2019-03-05 2:36 ` Masami Hiramatsu
2019-03-05 8:22 ` Masami Hiramatsu
2019-03-05 9:01 ` Masami Hiramatsu
2019-03-05 9:07 ` Peter Zijlstra
2019-03-05 13:58 ` Masami Hiramatsu
2019-03-05 14:53 ` Peter Zijlstra
2019-03-05 15:18 ` Masami Hiramatsu
2019-03-04 3:20 ` [LKP] " Rong Chen
2019-02-28 16:03 ` [PATCH v5 3/6] uaccess: Add non-pagefault user-space read functions Masami Hiramatsu
2019-02-28 22:49 ` Yonghong Song
2019-03-01 2:29 ` Masami Hiramatsu
2019-03-01 6:30 ` Yonghong Song
2019-02-28 16:04 ` [PATCH v5 4/6] tracing/probe: Add ustring type for user-space string Masami Hiramatsu
2019-02-28 16:04 ` [PATCH v5 5/6] tracing/probe: Support user-space dereference Masami Hiramatsu
2019-02-28 16:05 ` [PATCH v5 6/6] selftests/ftrace: Add user-memory access syntax testcase Masami Hiramatsu
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