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perf tools: Remove evsel__handle_error_quirks()
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[ Upstream commit 2b70702 ]

The evsel__handle_error_quirks() is to fixup invalid event attributes on
some architecture based on the error code.  Currently it's only used for
AMD to disable precise_ip not to use IBS which has more restrictions.

But the commit c33aea4 changed call evsel__precise_ip_fallback
for any errors so there's no difference with the above function.  To
make matter worse, it caused a problem with branch stack on Zen3.

The IBS doesn't support branch stack so it should use a regular core
PMU event.  The default event is set precise_max and it starts with 3.
And evsel__precise_ip_fallback() tries with it and reduces the level one
by one.  At last it tries with 0 but it also failed on Zen3 since the
branch stack is not supported for the cycles event.

At this point, evsel__precise_ip_fallback() restores the original
precise_ip value (3) in the hope that it can succeed with other modifier
(like exclude_kernel).  Then evsel__handle_error_quirks() see it has
precise_ip != 0 and make it retry with 0.  This created an infinite
loop.

Before:

  $ perf record -b -vv |& grep removing
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  ...

After:

  $ perf record -b true
  Error:
  Failure to open event 'cycles:P' on PMU 'cpu' which will be removed.
  Invalid event (cycles:P) in per-thread mode, enable system wide with '-a'.
  Error:
  Failure to open any events for recording.

Fixes: c33aea4 ("perf tools: Fix precise_ip fallback logic")
Tested-by: Chun-Tse Shao <ctshao@google.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20250410010252.402221-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Namhyung Kim authored and Greg Kroah-Hartman committed Apr 25, 2025
1 parent 54c0ff9 commit 716fb38
Showing 1 changed file with 0 additions and 22 deletions.
22 changes: 0 additions & 22 deletions tools/perf/util/evsel.c
Original file line number Diff line number Diff line change
Expand Up @@ -2556,25 +2556,6 @@ static bool evsel__detect_missing_features(struct evsel *evsel, struct perf_cpu
return false;
}

static bool evsel__handle_error_quirks(struct evsel *evsel, int error)
{
/*
* AMD core PMU tries to forward events with precise_ip to IBS PMU
* implicitly. But IBS PMU has more restrictions so it can fail with
* supported event attributes. Let's forward it back to the core PMU
* by clearing precise_ip only if it's from precise_max (:P).
*/
if ((error == -EINVAL || error == -ENOENT) && x86__is_amd_cpu() &&
evsel->core.attr.precise_ip && evsel->precise_max) {
evsel->core.attr.precise_ip = 0;
pr_debug2_peo("removing precise_ip on AMD\n");
display_attr(&evsel->core.attr);
return true;
}

return false;
}

static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
struct perf_thread_map *threads,
int start_cpu_map_idx, int end_cpu_map_idx)
Expand Down Expand Up @@ -2720,9 +2701,6 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
if (evsel__precise_ip_fallback(evsel))
goto retry_open;

if (evsel__handle_error_quirks(evsel, err))
goto retry_open;

out_close:
if (err)
threads->err_thread = thread;
Expand Down

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