[PATCH AUTOSEL 6.18] perf/x86/intel/uncore: Skip discovery table for offline dies

[Sasha Levin]

From: Zide Chen <zide.chen@xxxxxxxxx>

[ Upstream commit 7b568e9eba2fad89a696f22f0413d44cf4a1f892 ]

This warning can be triggered if NUMA is disabled and the system
boots with fewer CPUs than the number of CPUs in die 0.

WARNING: CPU: 9 PID: 7257 at uncore.c:1157 uncore_pci_pmu_register+0x136/0x160 [intel_uncore]

Currently, the discovery table continues to be parsed even if all CPUs
in the associated die are offline.  This can lead to an array overflow
at "pmu->boxes[die] = box" in uncore_pci_pmu_register(), which may
trigger the warning above or cause other issues.

Fixes: edae1f06c2cd ("perf/x86/intel/uncore: Parse uncore discovery tables")
Reported-by: Steve Wahl <steve.wahl@xxxxxxx>
Signed-off-by: Zide Chen <zide.chen@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
Tested-by: Steve Wahl <steve.wahl@xxxxxxx>
Link: https://patch.msgid.link/20260313174050.171704-3-zide.chen@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---

LLM Generated explanations, may be completely bogus:

Error: Failed to generate final synthesis

 arch/x86/events/intel/uncore_discovery.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
index 7d57ce706feb1..c5adbe4409047 100644
--- a/arch/x86/events/intel/uncore_discovery.c
+++ b/arch/x86/events/intel/uncore_discovery.c
@@ -383,7 +383,7 @@ static bool intel_uncore_has_discovery_tables_pci(int *ignore)
 				     (val & UNCORE_DISCOVERY_DVSEC2_BIR_MASK) * UNCORE_DISCOVERY_BIR_STEP;
 
 			die = get_device_die_id(dev);
-			if (die < 0)
+			if ((die < 0) || (die >= uncore_max_dies()))
 				continue;
 
 			parse_discovery_table(dev, die, bar_offset, &parsed, ignore);
-- 
2.53.0