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From: Masami Hiramatsu <mhiramat@kernel.org>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	"Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	Ananth N Mavinakayanahalli <ananth@linux.ibm.com>,
	Ingo Molnar <mingo@kernel.org>,
	linux-kernel@vger.kernel.org, Sven Schnelle <svens@linux.ibm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 6/8] ARM: clang: Do not relay on lr register for stacktrace
Date: Fri, 15 Oct 2021 09:18:32 +0900	[thread overview]
Message-ID: <20211015091832.3e114751496041931f214bab@kernel.org> (raw)
In-Reply-To: <YWhghNxpJD51ZDgD@shell.armlinux.org.uk>

On Thu, 14 Oct 2021 17:53:24 +0100
"Russell King (Oracle)" <linux@armlinux.org.uk> wrote:

> On Fri, Oct 08, 2021 at 09:29:08PM +0900, Masami Hiramatsu wrote:
> > Currently the stacktrace on clang compiled arm kernel uses the 'lr'
> > register to find the first frame address from pt_regs. However, that
> > is wrong after calling another function, because the 'lr' register
> > is used by 'bl' instruction and never be recovered.
> > 
> > As same as gcc arm kernel, directly use the frame pointer (x11) of
> > the pt_regs to find the first frame address.
> 
> Can I ask that the subject line is corrected. It's "rely" not "relay".

Oops, yes, that's my typo. Thanks for correcting!

> 
> Also, the frame pointer is called "r11" not "x11" if you want to use
> the numerical register reference for 32-bit ARM registers.

Oh, I mixed up the register name between arm64 and ARM...

Thank you,

> 
> Thanks.
> 
> -- 
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!


-- 
Masami Hiramatsu <mhiramat@kernel.org>

  reply	other threads:[~2021-10-15  0:18 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-08 12:28 [PATCH 0/8] kprobes: Make KUnit and add stacktrace on kretprobe tests Masami Hiramatsu
2021-10-08 12:28 ` [PATCH 1/8] kprobes: convert tests to kunit Masami Hiramatsu
2021-10-08 12:28 ` [PATCH 2/8] kprobes: Add a test case for stacktrace from kretprobe handler Masami Hiramatsu
2021-10-08 12:28 ` [PATCH 3/8] arm64: kprobes: Record frame pointer with kretprobe instance Masami Hiramatsu
2021-10-13  8:14   ` Will Deacon
2021-10-13 10:01   ` Mark Rutland
2021-10-14  8:04     ` Masami Hiramatsu
2021-10-14  9:13       ` Mark Rutland
2021-10-14 10:01         ` Masami Hiramatsu
2021-10-14 10:27           ` Mark Rutland
2021-10-14 13:50             ` Masami Hiramatsu
2021-10-08 12:28 ` [PATCH 4/8] arm64: kprobes: Make a frame pointer on __kretprobe_trampoline Masami Hiramatsu
2021-10-13  8:14   ` Will Deacon
2021-10-08 12:28 ` [PATCH 5/8] arm64: Recover kretprobe modified return address in stacktrace Masami Hiramatsu
2021-10-13  8:14   ` Will Deacon
2021-10-14  8:05     ` Masami Hiramatsu
2021-10-13 10:13   ` Mark Rutland
2021-10-14  9:57     ` Masami Hiramatsu
2021-10-08 12:29 ` [PATCH 6/8] ARM: clang: Do not relay on lr register for stacktrace Masami Hiramatsu
2021-10-11 18:45   ` Nick Desaulniers
2021-10-12 14:18     ` Masami Hiramatsu
2021-10-13 19:54       ` Nick Desaulniers
2021-10-14 16:53   ` Russell King (Oracle)
2021-10-15  0:18     ` Masami Hiramatsu [this message]
2021-10-08 12:29 ` [PATCH 7/8] ARM: kprobes: Make a frame pointer on __kretprobe_trampoline Masami Hiramatsu
2021-10-11 19:06   ` Nick Desaulniers
2021-10-08 12:29 ` [PATCH 8/8] ARM: Recover kretprobe modified return address in stacktrace Masami Hiramatsu

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