From: Ralf Baechle <ralf@linux-mips.org>
To: Harvey Hunt <harvey.hunt@imgtec.com>
Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org,
"# 4 . 2 . x-" <stable@vger.kernel.org>
Subject: Re: [PATCH] MIPS: lib: Mark intrinsics notrace
Date: Sun, 29 May 2016 23:03:41 +0200 [thread overview]
Message-ID: <20160529210340.GA25587@linux-mips.org> (raw)
In-Reply-To: <20160525100635.22541-1-harvey.hunt@imgtec.com>
On Wed, May 25, 2016 at 11:06:35AM +0100, Harvey Hunt wrote:
> On certain MIPS32 devices, the ftrace tracer "function_graph" uses
> __lshrdi3() during the capturing of trace data. ftrace then attempts to
> trace __lshrdi3() which leads to infinite recursion and a stack overflow.
> Fix this by marking __lshrdi3() as notrace. Mark the other compiler
> intrinsics as notrace in case the compiler decides to use them in the
> ftrace path.
Makes perfect sense - but I'm wondering how you triggered it. Was this
a build with the GCC option -Os that is CONFIG_CC_OPTIMIZE_FOR_SIZE?
Usually people build with CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE that is -O2
which results in intrinsics being inlined.
Ralf
next prev parent reply other threads:[~2016-05-29 21:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-25 10:06 [PATCH] MIPS: lib: Mark intrinsics notrace Harvey Hunt
2016-05-25 10:06 ` Harvey Hunt
2016-05-29 21:03 ` Ralf Baechle [this message]
2016-05-31 12:18 ` Harvey Hunt
2016-05-31 12:18 ` Harvey Hunt
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