linux-kernel - [PATCH RESEND] PCI/AER: Check for NULL aer_info before ratelimiting in pci_print

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Message-Id: <20250929-aer_crash_2-v1-1-68ec4f81c356@debian.org>
Date: Mon, 29 Sep 2025 02:15:47 -0700
From: Breno Leitao <leitao@...ian.org>
To: Mahesh J Salgaonkar <mahesh@...ux.ibm.com>, 
 Oliver O'Halloran <oohall@...il.com>, Bjorn Helgaas <bhelgaas@...gle.com>, 
 Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>, 
 Jon Pan-Doh <pandoh@...gle.com>
Cc: linuxppc-dev@...ts.ozlabs.org, linux-pci@...r.kernel.org, 
 linux-kernel@...r.kernel.org, kernel-team@...a.com, stable@...r.kernel.org, 
 Breno Leitao <leitao@...ian.org>
Subject: [PATCH RESEND] PCI/AER: Check for NULL aer_info before
 ratelimiting in pci_print_aer()

Similarly to pci_dev_aer_stats_incr(), pci_print_aer() may be called
when dev->aer_info is NULL. Add a NULL check before proceeding to avoid
calling aer_ratelimit() with a NULL aer_info pointer, returning 1, which
does not rate limit, given this is fatal.

This prevents a kernel crash triggered by dereferencing a NULL pointer
in aer_ratelimit(), ensuring safer handling of PCI devices that lack
AER info. This change aligns pci_print_aer() with pci_dev_aer_stats_incr()
which already performs this NULL check.

Cc: stable@...r.kernel.org
Fixes: a57f2bfb4a5863 ("PCI/AER: Ratelimit correctable and non-fatal error logging")
Signed-off-by: Breno Leitao <leitao@...ian.org>
---
- This problem is still happening in upstream, and unfortunately no action
  was done in the previous discussion.
- Link to previous post:
  https://lore.kernel.org/r/20250804-aer_crash_2-v1-1-fd06562c18a4@debian.org
---
 drivers/pci/pcie/aer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index e286c197d7167..55abc5e17b8b1 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -786,6 +786,9 @@ static void pci_rootport_aer_stats_incr(struct pci_dev *pdev,
 
 static int aer_ratelimit(struct pci_dev *dev, unsigned int severity)
 {
+	if (!dev->aer_info)
+		return 1;
+
 	switch (severity) {
 	case AER_NONFATAL:
 		return __ratelimit(&dev->aer_info->nonfatal_ratelimit);

---
base-commit: e5f0a698b34ed76002dc5cff3804a61c80233a7a
change-id: 20250801-aer_crash_2-b21cc2ef0d00

Best regards,
--  
Breno Leitao <leitao@...ian.org>