PCI: Check for alloc failure in pci_request_irq()

When kvasprintf() fails to allocate memory, it returns a NULL pointer.
Return error from pci_request_irq() so we don't dereference it.

[bhelgaas: commit log]
Fixes: 704e8953 ("PCI/irq: Add pci_request_irq() and pci_free_irq() helpers")
Link: https://lore.kernel.org/r/20221121020029.3759444-1-zengheng4@huawei.comSigned-off-by: NZeng Heng <zengheng4@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

drivers/pci/irq.c

@@ -44,6 +44,8 @@ int pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler,
 	va_start(ap, fmt);
 	devname = kvasprintf(GFP_KERNEL, fmt, ap);
 	va_end(ap);
+	if (!devname)
+		return -ENOMEM;
 
 	ret = request_threaded_irq(pci_irq_vector(dev, nr), handler, thread_fn,
 				   irqflags, devname, dev_id);