From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>
Subject: Re: [RFD] x86: The future of MPX
Date: Sat, 28 Apr 2018 19:50:43 +0200 [thread overview]
Message-ID: <20180428175043.y35czmhcursyrzsy@gmail.com> (raw)
In-Reply-To: <CA+55aFwgcmpSoNh17Pbtsw8j8KzufdvroC9Rsd3K-UbTTP9qPg@mail.gmail.com>
* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Sat, Apr 28, 2018 at 2:18 AM Ingo Molnar <mingo@kernel.org> wrote:
>
> > I just tried the MPX testcases with the latest kernel:
>
> > deimos:~/tip/tools/testing/selftests/x86> ./mpx-mini-test_64
>
> They need to be run as root. They try to access
>
> /sys/kernel/debug/tracing/set_ftrace_pid
> /sys/kernel/debug/tracing/trace
>
> and that's root-only.
Indeed - but note that they are crashing as root as well here:
root@deimos:/home/mingo/tip/tools/testing/selftests/x86# ./mpx-mini-test_64
[...]
Aborted (core dumped)
... because I don't even have /sys/kernel/debug/tracing/set_ftrace_pid... :-/
That's despite having ftrace enabled.
After some digging I found out that 'set_ftrace_pid' is dependent on
CONFIG_FUNCTION_TRACING=y (not just CONFIG_TRACING=y), which I didn't
have enabled on this kernel.
After enabling it I got the 64-bit testcase to work:
#
...
./mpx-mini-test_64 completed successfully
But the 32-bit testcase is erroring out:
root@deimos:/home/mingo/tip/tools/testing/selftests/x86# ./mpx-mini-test_32
XSAVE is supported by HW & OS
XSAVE processor supported state mask: 0x21f
XSAVE OS supported state mask: 0x21f
BNDREGS: size: 64 user: 1 supervisor: 0 aligned: 0
BNDCSR: size: 64 user: 1 supervisor: 0 aligned: 0
executing unmaptest
mpx dig ( 1) complete, SUCCESS ( 0 / 0)
#BR status == 2, missing bounds table,kernel should have handled!!
v4.17-rc2 based kernel, so it should have the latest MPX code.
Thanks,
Ingo
next prev parent reply other threads:[~2018-04-28 17:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-27 19:37 Thomas Gleixner
2018-04-28 9:18 ` Ingo Molnar
2018-04-28 16:36 ` Linus Torvalds
2018-04-28 16:44 ` Linus Torvalds
2018-04-30 4:44 ` Dave Hansen
2018-05-02 14:00 ` Borislav Petkov
2018-05-03 16:23 ` Eric W. Biederman
2018-04-28 17:50 ` Ingo Molnar [this message]
2018-04-29 4:46 ` Eric W. Biederman
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