* [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions
@ 2015-07-31 14:04 Jan Kiszka
2015-09-15 16:30 ` Jan Kiszka
2015-09-17 18:11 ` Steven Rostedt
0 siblings, 2 replies; 6+ messages in thread
From: Jan Kiszka @ 2015-07-31 14:04 UTC (permalink / raw)
To: Steven Rostedt, Linux Kernel Mailing List
On x86, page_fault_* tracepoints report userspace address via kernel
symbols because all the per-cpu variable offsets are in kallsyms,
occupying the lower address space. Fix this by skipping over absolute
addresses while processing kallsyms.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
trace-util.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/trace-util.c b/trace-util.c
index 8a81dd0..da20e4c 100644
--- a/trace-util.c
+++ b/trace-util.c
@@ -434,8 +434,12 @@ void parse_proc_kallsyms(struct pevent *pevent,
if (mod)
mod[strlen(mod) - 1] = 0;
- /* Hack for arm arch that adds a lot of bogus '$a' functions */
- if (func[0] != '$')
+ /*
+ * Hacks for
+ * - arm arch that adds a lot of bogus '$a' functions
+ * - x86-64 that reports per-cpu variable offsets as absolute
+ */
+ if (func[0] != '$' && ch != 'A')
pevent_register_function(pevent, func, addr, mod);
free(func);
free(mod);
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions
2015-07-31 14:04 [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions Jan Kiszka
@ 2015-09-15 16:30 ` Jan Kiszka
2015-09-15 17:00 ` Steven Rostedt
2015-09-17 18:11 ` Steven Rostedt
1 sibling, 1 reply; 6+ messages in thread
From: Jan Kiszka @ 2015-09-15 16:30 UTC (permalink / raw)
To: Steven Rostedt, Linux Kernel Mailing List
On 2015-07-31 16:04, Jan Kiszka wrote:
> On x86, page_fault_* tracepoints report userspace address via kernel
> symbols because all the per-cpu variable offsets are in kallsyms,
> occupying the lower address space. Fix this by skipping over absolute
> addresses while processing kallsyms.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
> trace-util.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/trace-util.c b/trace-util.c
> index 8a81dd0..da20e4c 100644
> --- a/trace-util.c
> +++ b/trace-util.c
> @@ -434,8 +434,12 @@ void parse_proc_kallsyms(struct pevent *pevent,
> if (mod)
> mod[strlen(mod) - 1] = 0;
>
> - /* Hack for arm arch that adds a lot of bogus '$a' functions */
> - if (func[0] != '$')
> + /*
> + * Hacks for
> + * - arm arch that adds a lot of bogus '$a' functions
> + * - x86-64 that reports per-cpu variable offsets as absolute
> + */
> + if (func[0] != '$' && ch != 'A')
> pevent_register_function(pevent, func, addr, mod);
> free(func);
> free(mod);
>
Ping.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions
2015-09-15 16:30 ` Jan Kiszka
@ 2015-09-15 17:00 ` Steven Rostedt
2015-09-15 17:06 ` Jan Kiszka
0 siblings, 1 reply; 6+ messages in thread
From: Steven Rostedt @ 2015-09-15 17:00 UTC (permalink / raw)
To: Jan Kiszka; +Cc: Linux Kernel Mailing List
On Tue, 15 Sep 2015 18:30:22 +0200
Jan Kiszka <jan.kiszka@siemens.com> wrote:
> On 2015-07-31 16:04, Jan Kiszka wrote:
> > On x86, page_fault_* tracepoints report userspace address via kernel
> > symbols because all the per-cpu variable offsets are in kallsyms,
> > occupying the lower address space. Fix this by skipping over absolute
> > addresses while processing kallsyms.
> >
> > Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> > ---
> > trace-util.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/trace-util.c b/trace-util.c
> > index 8a81dd0..da20e4c 100644
> > --- a/trace-util.c
> > +++ b/trace-util.c
> > @@ -434,8 +434,12 @@ void parse_proc_kallsyms(struct pevent *pevent,
> > if (mod)
> > mod[strlen(mod) - 1] = 0;
> >
> > - /* Hack for arm arch that adds a lot of bogus '$a' functions */
> > - if (func[0] != '$')
> > + /*
> > + * Hacks for
> > + * - arm arch that adds a lot of bogus '$a' functions
> > + * - x86-64 that reports per-cpu variable offsets as absolute
> > + */
> > + if (func[0] != '$' && ch != 'A')
> > pevent_register_function(pevent, func, addr, mod);
> > free(func);
> > free(mod);
> >
>
> Ping.
Thanks for the reminder ping.
Hmm, I don't see anything marked 'A' in my kallsyms. Have a config I
can test to see what you are seeing?
-- Steve
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions
2015-09-15 17:00 ` Steven Rostedt
@ 2015-09-15 17:06 ` Jan Kiszka
2015-09-15 17:17 ` Steven Rostedt
0 siblings, 1 reply; 6+ messages in thread
From: Jan Kiszka @ 2015-09-15 17:06 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Linux Kernel Mailing List
[-- Attachment #1: Type: text/plain, Size: 1710 bytes --]
On 2015-09-15 19:00, Steven Rostedt wrote:
> On Tue, 15 Sep 2015 18:30:22 +0200
> Jan Kiszka <jan.kiszka@siemens.com> wrote:
>
>> On 2015-07-31 16:04, Jan Kiszka wrote:
>>> On x86, page_fault_* tracepoints report userspace address via kernel
>>> symbols because all the per-cpu variable offsets are in kallsyms,
>>> occupying the lower address space. Fix this by skipping over absolute
>>> addresses while processing kallsyms.
>>>
>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>> ---
>>> trace-util.c | 8 ++++++--
>>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/trace-util.c b/trace-util.c
>>> index 8a81dd0..da20e4c 100644
>>> --- a/trace-util.c
>>> +++ b/trace-util.c
>>> @@ -434,8 +434,12 @@ void parse_proc_kallsyms(struct pevent *pevent,
>>> if (mod)
>>> mod[strlen(mod) - 1] = 0;
>>>
>>> - /* Hack for arm arch that adds a lot of bogus '$a' functions */
>>> - if (func[0] != '$')
>>> + /*
>>> + * Hacks for
>>> + * - arm arch that adds a lot of bogus '$a' functions
>>> + * - x86-64 that reports per-cpu variable offsets as absolute
>>> + */
>>> + if (func[0] != '$' && ch != 'A')
>>> pevent_register_function(pevent, func, addr, mod);
>>> free(func);
>>> free(mod);
>>>
>>
>> Ping.
>
> Thanks for the reminder ping.
>
> Hmm, I don't see anything marked 'A' in my kallsyms. Have a config I
> can test to see what you are seeing?
Huh? Your /proc/kallsyms doesn't start like this?
0000000000000000 A irq_stack_union
0000000000000000 A __per_cpu_start
...
That's from a stock distro SUSE kernel I'm running (config attached).
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
[-- Attachment #2: config-4.2.0-4.g9f67920-desktop.xz --]
[-- Type: application/x-xz, Size: 35516 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions
2015-09-15 17:06 ` Jan Kiszka
@ 2015-09-15 17:17 ` Steven Rostedt
0 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2015-09-15 17:17 UTC (permalink / raw)
To: Jan Kiszka; +Cc: Linux Kernel Mailing List
On Tue, 15 Sep 2015 19:06:36 +0200
Jan Kiszka <jan.kiszka@siemens.com> wrote:
> Huh? Your /proc/kallsyms doesn't start like this?
>
> 0000000000000000 A irq_stack_union
> 0000000000000000 A __per_cpu_start
> ...
>
> That's from a stock distro SUSE kernel I'm running (config attached).
Nevermind, I was looking at an older kernel which didn't have that. I
booted a newer kernel and I now see it.
-- Steve
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions
2015-07-31 14:04 [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions Jan Kiszka
2015-09-15 16:30 ` Jan Kiszka
@ 2015-09-17 18:11 ` Steven Rostedt
1 sibling, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2015-09-17 18:11 UTC (permalink / raw)
To: Jan Kiszka; +Cc: Linux Kernel Mailing List
On Fri, 31 Jul 2015 16:04:54 +0200
Jan Kiszka <jan.kiszka@siemens.com> wrote:
> On x86, page_fault_* tracepoints report userspace address via kernel
> symbols because all the per-cpu variable offsets are in kallsyms,
> occupying the lower address space. Fix this by skipping over absolute
> addresses while processing kallsyms.
Applied thanks!
-- Steve
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
> trace-util.c | 8 ++++++--
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2015-09-17 18:11 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2015-07-31 14:04 [PATCH] trace-cmd: Leave out absolute addresses to fix bogus symbol resolutions Jan Kiszka
2015-09-15 16:30 ` Jan Kiszka
2015-09-15 17:00 ` Steven Rostedt
2015-09-15 17:06 ` Jan Kiszka
2015-09-15 17:17 ` Steven Rostedt
2015-09-17 18:11 ` Steven Rostedt
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