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perf/hw_breakpoint: Return EOPNOTSUPP for unsupported breakpoint type

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[ Upstream commit 061c991697 ]

Currently, __reserve_bp_slot() returns -ENOSPC for unsupported
breakpoint types on the architecture. For example, powerpc
does not support hardware instruction breakpoints. This causes
the perf_skip BPF selftest to fail, as neither ENOENT nor
EOPNOTSUPP is returned by perf_event_open for unsupported
breakpoint types. As a result, the test that should be skipped
for this arch is not correctly identified.

To resolve this, hw_breakpoint_event_init() should exit early by
checking for unsupported breakpoint types using
hw_breakpoint_slots_cached() and return the appropriate error
(-EOPNOTSUPP).

Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: https://lore.kernel.org/r/20250303092451.1862862-1-skb99@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Saket Kumar Bhaskar 2025-03-03 14:54:51 +05:30 committed by Greg Kroah-Hartman
parent 48bd9b9d66
commit 628ff556e4
1 changed files with 3 additions and 2 deletions
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5
kernel/events/hw_breakpoint.c
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@ -978,9 +978,10 @@ static int hw_breakpoint_event_init(struct perf_event *bp)
return -ENOENT;
/*
* no branch sampling for breakpoint events
* Check if breakpoint type is supported before proceeding.
* Also, no branch sampling for breakpoint events.
*/
if (has_branch_stack(bp))
if (!hw_breakpoint_slots_cached(find_slot_idx(bp->attr.bp_type)) || has_branch_stack(bp))
return -EOPNOTSUPP;
err = register_perf_hw_breakpoint(bp);