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From: Puranjay Mohan <puranjay12@gmail.com>
Date: Fri, 14 Jun 2024 14:14:50 +0200
Message-ID: <CANk7y0hEQVTRTZWCJiC8d8pmQVy7fvdL_qQM_Sa__YuBa-5s=A@mail.gmail.com>
Subject: Re: selftests: ftrace: WARNING: at arch/arm64/kernel/stacktrace.c:112 arch_stack_walk
To: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: open list <linux-kernel@vger.kernel.org>, 
	Linux ARM <linux-arm-kernel@lists.infradead.org>, lkft-triage@lists.linaro.org, 
	Linux Regressions <regressions@lists.linux.dev>, 
	"open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest@vger.kernel.org>, Catalin Marinas <catalin.marinas@arm.com>, 
	Nianyao Tang <tangnianyao@huawei.com>, Mark Rutland <mark.rutland@arm.com>, 
	Stephen Boyd <swboyd@chromium.org>, Puranjay Mohan <puranjay@kernel.org>, 
	James Morse <james.morse@arm.com>, Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@arndb.de>, 
	Dan Carpenter <dan.carpenter@linaro.org>, Anders Roxell <anders.roxell@linaro.org>, 
	Steven Rostedt <rostedt@goodmis.org>, Masami Hiramatsu <mhiramat@kernel.org>
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Hi Naresh,

Thanks for finding this.

On Thu, Jun 13, 2024 at 3:16=E2=80=AFPM Naresh Kamboju
<naresh.kamboju@linaro.org> wrote:
>
> The following kernel warning noticed on arm64 qemu-arm64 and rk3399-rock-=
pi-4
> device while running selftests ftrace tests on Linux next-20240613.
>
> This is always reproducible on qemu-arm64 and rock-pi-4 device with
> kselftest merge configs
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>
> Test log:
> -------
> kselftest: Running tests in ftrace
> TAP version 13
> 1..1
> # timeout set to 0
> # selftests: ftrace: ftracetest-ktap
> # unlink: cannot unlink
> '/opt/kselftests/default-in-kernel/ftrace/logs/latest': No such file
> or directory
> # TAP version 13
> # 1..141
> # ok 1 Basic trace file check
> <4>[   96.183553] ------------[ cut here ]------------
> <4>[ 96.187100] WARNING: CPU: 1 PID: 538 at
> arch/arm64/kernel/stacktrace.c:112 arch_stack_walk


29c1c24a2707 ("function_graph: Fix up ftrace_graph_ret_addr()") made
the ftrace_graph_ret_addr() use the
'idx' pointer to optimise the stack unwinding but arm64, riscv, and
some other architectures pass `NULL` for this
parameter. The fix for this is to pass a valid pointer to
ftrace_graph_ret_addr() like x86_64 is doing.

I will send a patch to fix this unless someone else has already sent one.

Thanks,
Puranjay