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From: Greg KH <gregkh@linuxfoundation.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	LKML <linux-kernel@vger.kernel.org>,
	stable@vger.kernel.org, Namhyung Kim <namhyung@kernel.org>
Subject: Re: [PATCH] tracing: Fix align of static buffer
Date: Thu, 26 Nov 2020 06:52:07 +0100	[thread overview]
Message-ID: <X79Ch+WDwYwqWGk8@kroah.com> (raw)
In-Reply-To: <20201125225654.1618966-1-minchan@kernel.org>

On Wed, Nov 25, 2020 at 02:56:54PM -0800, Minchan Kim wrote:
> With 5.9 kernel on ARM64, I found ftrace_dump output was broken but
> it had no problem with normal output "cat /sys/kernel/debug/tracing/trace".
> 
> With investigation, it seems coping the data into temporal buffer seems to
> break the align binary printf expects if the static buffer is not aligned
> with 4-byte. IIUC, get_arg in bstr_printf expects that args has already
> right align to be decoded and seq_buf_bprintf says ``the arguments are saved
> in a 32bit word array that is defined by the format string constraints``.
> So if we don't keep the align under copy to temporal buffer, the output
> will be broken by shifting some bytes.
> 
> This patch fixes it.

Does this resolve the issue reported at:
	https://lore.kernel.org/r/20201124223917.795844-1-elavila@google.com
?

thanks,

greg k-h

  reply	other threads:[~2020-11-26  5:52 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-25 22:56 [PATCH] tracing: Fix align of static buffer Minchan Kim
2020-11-26  5:52 ` Greg KH [this message]
2020-11-26  9:31   ` Namhyung Kim
     [not found] ` <CGME20201126124101epcas2p30b7039bc8e6a9c08e35487b39dd84767@epcas2p3.samsung.com>
2020-11-26 13:04   ` Youngmin Nam
2020-11-26 18:05     ` Minchan Kim

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