On Mon, Jan 11, 2021 at 02:39:20PM +0100, Hinko Kocevar wrote:
> Testing this patch a bit more (without the 5/5) resulted in the same CPU
> lockup:
>
> watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [irq/122-aerdrv:128]
>
> as I initially reported with the 5/5 of this patch included.
>
> It seems more infrequent, though. For example, after reboot this is not
> observed and the recovery process is successful, whereas when 5/5 is also
> used every recovery resulted in CPU lockup.
I am assuming this soft lockup is still when restoring the downstream
port's virtual channel capability. Your initial sighting indicates that
it doesn't appear to be a deadlock, but the stack trace never existed
pci_restore_vc_state() either. I did not find any obvious issues here
just from code inspection, so if you could try applying the following
patch and send the kernel messages output, that would help.
---
diff --git a/drivers/pci/vc.c b/drivers/pci/vc.c
index 5fc59ac31145..4834af7eb582 100644
--- a/drivers/pci/vc.c
+++ b/drivers/pci/vc.c
@@ -28,6 +28,7 @@ static void pci_vc_save_restore_dwords(struct pci_dev *dev, int pos,
{
int i;
+ pci_warn(dev, "%s: pos:%d dwords:%d\n", __func__, pos, dwords);
for (i = 0; i < dwords; i++, buf++) {
if (save)
pci_read_config_dword(dev, pos + (i * 4), buf);
@@ -110,6 +111,8 @@ static void pci_vc_enable(struct pci_dev *dev, int pos, int res)
if (!pci_is_pcie(dev) || !pcie_downstream_port(dev))
return;
+ pci_warn(dev, "%s: pos:%d res:%d\n", __func__, pos, res);
+
ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF);
status_pos = pos + PCI_VC_RES_STATUS + (res * PCI_CAP_VC_PER_VC_SIZEOF);
@@ -165,6 +168,8 @@ static void pci_vc_enable(struct pci_dev *dev, int pos, int res)
if (link && !pci_wait_for_pending(link, status_pos2,
PCI_VC_RES_STATUS_NEGO))
pci_err(link, "VC%d negotiation stuck pending\n", id);
+
+ pci_warn(dev, "%s: pos:%d res:%d return\n", __func__, pos, res);
}
/**
@@ -190,6 +195,7 @@ static int pci_vc_do_save_buffer(struct pci_dev *dev, int pos,
int i, len = 0;
u8 *buf = save_state ? (u8 *)save_state->cap.data : NULL;
+ pci_warn(dev, "%s: buf:%d pos:%d\n", __func__, buf != NULL, pos);
/* Sanity check buffer size for save/restore */
if (buf && save_state->cap.size !=
pci_vc_do_save_buffer(dev, pos, NULL, save)) {
@@ -278,6 +284,8 @@ static int pci_vc_do_save_buffer(struct pci_dev *dev, int pos,
pci_read_config_dword(dev, pos + PCI_VC_RES_CAP +
(i * PCI_CAP_VC_PER_VC_SIZEOF), &cap);
parb_offset = ((cap & PCI_VC_RES_CAP_ARB_OFF) >> 24) * 16;
+ pci_warn(dev, "%s: i:%d evcc:%d parb_offset:%d\n", __func__, i,
+ evcc, parb_offset);
if (parb_offset) {
int size, parb_phases = 0;
@@ -332,6 +340,7 @@ static int pci_vc_do_save_buffer(struct pci_dev *dev, int pos,
len += 4;
}
+ pci_warn(dev, "%s: len:%d\n", __func__, len);
return buf ? 0 : len;
}
@@ -399,6 +408,7 @@ void pci_restore_vc_state(struct pci_dev *dev)
if (!save_state || !pos)
continue;
+ pci_warn(dev, "%s: i:%d pos:%d\n", __func__, i, pos);
pci_vc_do_save_buffer(dev, pos, save_state, false);
}
}
--
