Re: [PATCH RESEND] PCI/AER: Check for NULL aer_info before ratelimiting in pci_print_aer()
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2025-10-01 21:36:58
Also in:
linux-pci, lkml, stable
On Mon, Sep 29, 2025 at 02:15:47AM -0700, Breno Leitao wrote:
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@vger.kernel.org
Fixes: a57f2bfb4a5863 ("PCI/AER: Ratelimit correctable and non-fatal error logging")
Signed-off-by: Breno Leitao <leitao@debian.org>Thanks, Breno, I applied this to pci/aer for v6.18. I added a little more detail to the commit log because the path where we hit this is a bit obscure. Please take a look and see if it makes sense: https://git.kernel.org/cgit/linux/kernel/git/pci/pci.git/commit/?id=451f30b97807
quoted hunk ↗ jump to hunk
--- - 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 (local) --- 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 [off-list ref]