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From: Steven Rostedt <rostedt@goodmis.org>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	linuxppc-dev@lists.ozlabs.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 5/7] powerpc/ftrace: Update ftrace_location() for powerpc -mprofile-kernel
Date: Tue, 18 Jun 2019 11:45:09 -0400	[thread overview]
Message-ID: <20190618114509.5b1acbe5@gandalf.local.home> (raw)
In-Reply-To: <186656540d3e6225abd98374e791a13d10d86fab.1560868106.git.naveen.n.rao@linux.vnet.ibm.com>

On Tue, 18 Jun 2019 20:17:04 +0530
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:

> @@ -1551,7 +1551,7 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end)
>  	key.flags = end;	/* overload flags, as it is unsigned long */
>  
>  	for (pg = ftrace_pages_start; pg; pg = pg->next) {
> -		if (end < pg->records[0].ip ||
> +		if (end <= pg->records[0].ip ||

This breaks the algorithm. "end" is inclusive. That is, if you look for
a single byte, where "start" and "end" are the same, and it happens to
be the first ip on the pg page, it will be skipped, and not found.

-- Steve

>  		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
>  			continue;
>  		rec = bsearch(&key, pg->records, pg->index,

  reply	other threads:[~2019-06-18 15:47 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-18 14:46 [PATCH 0/7] powerpc/ftrace: Patch out -mprofile-kernel instructions Naveen N. Rao
2019-06-18 14:47 ` [PATCH 1/7] ftrace: Expose flags used for ftrace_replace_code() Naveen N. Rao
2019-06-18 14:47 ` [PATCH 2/7] x86/ftrace: Fix use of flags in ftrace_replace_code() Naveen N. Rao
2019-06-18 14:47 ` [PATCH 3/7] ftrace: Expose __ftrace_replace_code() Naveen N. Rao
2019-06-18 14:47 ` [PATCH 4/7] powerpc/ftrace: Additionally nop out the preceding mflr with -mprofile-kernel Naveen N. Rao
2019-06-19  5:14   ` Michael Ellerman
2019-06-19  7:10     ` Nicholas Piggin
2019-06-19  9:53       ` Naveen N. Rao
2019-06-19 10:41         ` Nicholas Piggin
2019-06-19 17:14           ` Naveen N. Rao
2019-06-18 14:47 ` [PATCH 5/7] powerpc/ftrace: Update ftrace_location() for powerpc -mprofile-kernel Naveen N. Rao
2019-06-18 15:45   ` Steven Rostedt [this message]
2019-06-18 18:11     ` Naveen N. Rao
2019-06-18 18:23       ` Naveen N. Rao
2019-06-18 18:32         ` Steven Rostedt
2019-06-19  7:56           ` Naveen N. Rao
2019-06-19  9:28             ` Steven Rostedt
2019-06-18 14:47 ` [PATCH 6/7] kprobes/ftrace: Use ftrace_location() when [dis]arming probes Naveen N. Rao
2019-06-21 14:41   ` Masami Hiramatsu
2019-06-18 14:47 ` [PATCH 7/7] powerpc/kprobes: Allow probing on any ftrace address Naveen N. Rao
2019-06-21 14:50   ` Masami Hiramatsu
2019-06-22  3:49     ` Joe Perches
2019-06-26  9:39     ` Naveen N. Rao

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