From: Björn Töpel <[email protected]>
In commit 613f050d68a8 ("perf probe: Fix to probe on gcc generated
functions in modules"), the offset from symbol is, incorrectly, added
to the trace point address. This leads to incorrect probe trace points
for inlined functions and when using relative line number on symbols.
Prior this patch:
$ perf probe -m nf_nat -D in_range
p:probe/in_range nf_nat:in_range.isra.9+0
$ perf probe -m i40e -D i40e_clean_rx_irq
p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2212
$ perf probe -m i40e -D i40e_clean_rx_irq:16
p:probe/i40e_clean_rx_irq i40e:i40e_lan_xmit_frame+626
After:
$ perf probe -m nf_nat -D in_range
p:probe/in_range nf_nat:in_range.isra.9+0
$ perf probe -m i40e -D i40e_clean_rx_irq
p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+1106
$ perf probe -m i40e -D i40e_clean_rx_irq:16
p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2665
Fixes: 613f050d68a8 ("perf probe: Fix to probe on gcc generated functions in modules")
Signed-off-by: Björn Töpel <[email protected]>
---
tools/perf/util/probe-event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 84e7e698411e..a2670e9d652d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -619,7 +619,7 @@ static int post_process_probe_trace_point(struct probe_trace_point *tp,
struct map *map, unsigned long offs)
{
struct symbol *sym;
- u64 addr = tp->address + tp->offset - offs;
+ u64 addr = tp->address - offs;
sym = map__find_symbol(map, addr);
if (!sym)
--
2.7.4
On Wed, 21 Jun 2017 18:41:34 +0200
Björn Töpel <[email protected]> wrote:
> From: Björn Töpel <[email protected]>
>
> In commit 613f050d68a8 ("perf probe: Fix to probe on gcc generated
> functions in modules"), the offset from symbol is, incorrectly, added
> to the trace point address. This leads to incorrect probe trace points
> for inlined functions and when using relative line number on symbols.
>
> Prior this patch:
> $ perf probe -m nf_nat -D in_range
> p:probe/in_range nf_nat:in_range.isra.9+0
> $ perf probe -m i40e -D i40e_clean_rx_irq
> p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2212
> $ perf probe -m i40e -D i40e_clean_rx_irq:16
> p:probe/i40e_clean_rx_irq i40e:i40e_lan_xmit_frame+626
>
> After:
> $ perf probe -m nf_nat -D in_range
> p:probe/in_range nf_nat:in_range.isra.9+0
> $ perf probe -m i40e -D i40e_clean_rx_irq
> p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+1106
> $ perf probe -m i40e -D i40e_clean_rx_irq:16
> p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2665
OK, I've confirmed it. This bug also affects -D option for
offline probes...
$ ./perf probe -k ~/kbin/linux.x86_64/vmlinux -vD vfs_read:11
probe-definition(0): vfs_read:11
[...]
Try to find probe point from debuginfo.
Matched function: vfs_read [28b211e]
Probe point found: vfs_read+90 <- here vfs_read+90
Found 1 probe_trace_events.
p:probe/vfs_read vfs_read+180 <- here vfs_read+180 = 90+90
So offset to be doubled...
Acked-by: Masami Hiramatsu <[email protected]>
Arnaldo, this should go to urgent/stable.
Thank you!
>
> Fixes: 613f050d68a8 ("perf probe: Fix to probe on gcc generated functions in modules")
> Signed-off-by: Björn Töpel <[email protected]>
> ---
> tools/perf/util/probe-event.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 84e7e698411e..a2670e9d652d 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -619,7 +619,7 @@ static int post_process_probe_trace_point(struct probe_trace_point *tp,
> struct map *map, unsigned long offs)
> {
> struct symbol *sym;
> - u64 addr = tp->address + tp->offset - offs;
> + u64 addr = tp->address - offs;
>
> sym = map__find_symbol(map, addr);
> if (!sym)
> --
> 2.7.4
>
> --
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> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Masami Hiramatsu <[email protected]>
Em Thu, Jun 22, 2017 at 07:01:38PM +0900, Masami Hiramatsu escreveu:
> On Wed, 21 Jun 2017 18:41:34 +0200
> Bj?rn T?pel <[email protected]> wrote:
>
> > From: Bj?rn T?pel <[email protected]>
> >
> > In commit 613f050d68a8 ("perf probe: Fix to probe on gcc generated
> > functions in modules"), the offset from symbol is, incorrectly, added
> > to the trace point address. This leads to incorrect probe trace points
> > for inlined functions and when using relative line number on symbols.
> >
> > Prior this patch:
> > $ perf probe -m nf_nat -D in_range
> > p:probe/in_range nf_nat:in_range.isra.9+0
> > $ perf probe -m i40e -D i40e_clean_rx_irq
> > p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2212
> > $ perf probe -m i40e -D i40e_clean_rx_irq:16
> > p:probe/i40e_clean_rx_irq i40e:i40e_lan_xmit_frame+626
> >
> > After:
> > $ perf probe -m nf_nat -D in_range
> > p:probe/in_range nf_nat:in_range.isra.9+0
> > $ perf probe -m i40e -D i40e_clean_rx_irq
> > p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+1106
> > $ perf probe -m i40e -D i40e_clean_rx_irq:16
> > p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2665
>
> OK, I've confirmed it. This bug also affects -D option for
> offline probes...
>
> $ ./perf probe -k ~/kbin/linux.x86_64/vmlinux -vD vfs_read:11
> probe-definition(0): vfs_read:11
> [...]
> Try to find probe point from debuginfo.
> Matched function: vfs_read [28b211e]
> Probe point found: vfs_read+90 <- here vfs_read+90
> Found 1 probe_trace_events.
> p:probe/vfs_read vfs_read+180 <- here vfs_read+180 = 90+90
>
> So offset to be doubled...
>
> Acked-by: Masami Hiramatsu <[email protected]>
>
> Arnaldo, this should go to urgent/stable.
Thanks for checking, I'll get it into tools/urgent and CC stable, the
Fixes tag should be enough for stable maintainers to figure out what
kernels should get it.
- Arnaldo