On Wed, 21 Jun 2017 18:41:34 +0200
Björn Töpel <bjorn.to...@gmail.com> wrote:
> From: Björn Töpel <bjorn.to...@intel.com>
>
> 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 <mhira...@kernel.org>
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 <bjorn.to...@intel.com>
> ---
> 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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--
Masami Hiramatsu <mhira...@kernel.org>
