[PATCH v5 2/3] PCI/AER: Fix memory leak in aer_recover_work_func() when pci_dev is missing

[Priyank Rathod <rathodpriyank@google.com>]

When ACPI APEI/GHES processes PCIe AER error records, it allocates memory
for aer_capability_regs (entry.regs) from ghes_estatus_pool and queues
the entry into aer_recover_ring.

In aer_recover_work_func(), items are popped from aer_recover_ring via
kfifo_get(). If pci_get_domain_bus_and_slot() fails to find a matching
pci_dev, the code previously executed 'continue', bypassing the call to
ghes_estatus_pool_region_free(). As a result, the memory allocated for
entry.regs from ghes_estatus_pool was leaked.

This is reachable whenever the device reported by firmware is not (or is
no longer) present in the PCI device tree, e.g. after hot-removal or when
firmware reports an error for a device the kernel never enumerated.

Refactor aer_recover_work_func() to ensure ghes_estatus_pool_region_free()
is called unconditionally for every dequeued entry, releasing the pool
memory even when pci_dev is missing.

Fixes: e2abc47a5a1a ("ACPI: APEI: Fix AER info corruption when error status data has multiple sections")
Cc: stable@vger.kernel.org
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Priyank Rathod <rathodpriyank@google.com>
---
 drivers/pci/pcie/aer.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index b013b853b555..a6600801af6e 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1366,14 +1366,13 @@ static void aer_recover_work_func(struct work_struct *work)
 	while (kfifo_get(&aer_recover_ring, &entry)) {
 		pdev = pci_get_domain_bus_and_slot(entry.domain, entry.bus,
 						   entry.devfn);
-		if (!pdev) {
+		if (!pdev)
 			pr_err_ratelimited("%04x:%02x:%02x.%x: no pci_dev found\n",
 					   entry.domain, entry.bus,
 					   PCI_SLOT(entry.devfn),
 					   PCI_FUNC(entry.devfn));
-			continue;
-		}
-		pci_print_aer(pdev, entry.severity, entry.regs);
+		else
+			pci_print_aer(pdev, entry.severity, entry.regs);
 
 		/*
 		 * Memory for aer_capability_regs(entry.regs) is being
@@ -1385,13 +1384,15 @@ static void aer_recover_work_func(struct work_struct *work)
 		ghes_estatus_pool_region_free((unsigned long)entry.regs,
 					    sizeof(struct aer_capability_regs));
 
-		if (entry.severity == AER_NONFATAL)
-			pcie_do_recovery(pdev, pci_channel_io_normal,
-					 aer_root_reset);
-		else if (entry.severity == AER_FATAL)
-			pcie_do_recovery(pdev, pci_channel_io_frozen,
-					 aer_root_reset);
-		pci_dev_put(pdev);
+		if (pdev) {
+			if (entry.severity == AER_NONFATAL)
+				pcie_do_recovery(pdev, pci_channel_io_normal,
+						 aer_root_reset);
+			else if (entry.severity == AER_FATAL)
+				pcie_do_recovery(pdev, pci_channel_io_frozen,
+						 aer_root_reset);
+			pci_dev_put(pdev);
+		}
 	}
 }
 

-- 
2.56.0.rc1.315.gc6ed9934b7-goog