[PATCH] ACPI: APEI: Avoid NULL pointer dereference in ghes_estatus_pool_region_free

[Jiawen Wu]

The function ghes_estatus_pool_region_free() is exported and be called
by the PCIe AER recovery path, which unconditionally invokes it to free
aer_capability_regs memory.

Although current AER usage assumes memory comes from the GHES pool,
robustness requires guarding against pool unavailability. Add a NULL check
before calling gen_pool_free() to prevent crashes when the pool is not
initialized. This also makes the API safer for potential future use by
non-GHES callers.

Fixes: e2abc47a5a1a ("ACPI: APEI: Fix AER info corruption when error status data has multiple sections")
Signed-off-by: Jiawen Wu <jiawenwu@xxxxxxxxxxxxxx>
---
 drivers/acpi/apei/ghes.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 0dc767392a6c..e81c007464a9 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -236,7 +236,8 @@ int ghes_estatus_pool_init(unsigned int num_ghes)
  */
 void ghes_estatus_pool_region_free(unsigned long addr, u32 size)
 {
-	gen_pool_free(ghes_estatus_pool, addr, size);
+	if (ghes_estatus_pool)
+		gen_pool_free(ghes_estatus_pool, addr, size);
 }
 EXPORT_SYMBOL_GPL(ghes_estatus_pool_region_free);
 
-- 
2.48.1