The following commit has been merged into the perf/core branch of tip: Commit-ID: 4118628d0ce005e5651174b9d5fc0209a8d49ee0 Gitweb: https://git.kernel.org/tip/4118628d0ce005e5651174b9d5fc0209a8d49ee0 Author: Saket Kumar Bhaskar <skb99@xxxxxxxxxxxxx> AuthorDate: Mon, 03 Mar 2025 14:54:51 +05:30 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Mon, 03 Mar 2025 13:24:12 +01:00 perf/hw_breakpoint: Return EOPNOTSUPP for unsupported breakpoint type 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@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Ian Rogers <irogers@xxxxxxxxxx> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx> Link: https://lore.kernel.org/r/20250303092451.1862862-1-skb99@xxxxxxxxxxxxx --- kernel/events/hw_breakpoint.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index bc4a610..8ec2cb6 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -950,9 +950,10 @@ 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);
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