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authorSaket Kumar Bhaskar <skb99@linux.ibm.com>2025-03-03 14:54:51 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-05-29 11:12:59 +0200
commit95e52e957879e9be17a1169fa32b7f5160965c58 (patch)
tree603c3788a059047ceb40757d1e009c3cb5e48745
parent19259fe0a68322aae91d5ab95504c3fe096376c6 (diff)
perf/hw_breakpoint: Return EOPNOTSUPP for unsupported breakpoint type
[ Upstream commit 061c991697062f3bf87b72ed553d1d33a0e370dd ] 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>
-rw-r--r--kernel/events/hw_breakpoint.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index bc4a61029b6d..8ec2cb688903 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);