Hi Borislav

-----Original Message-----
On Mon, Aug 22, 2022 at 03:40:42PM +0000, Jia He wrote:

quoted

Commit dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in
apci_init()") introduced a bug that ghes_edac_register() would be
invoked before edac_init(). Because at that time, the bus "edac"
hadn't been even registered, this created sysfs /devices/mc0 instead
of
/sys/devices/system/edac/mc/mc0 on an Ampere eMag server.

To remove the dependency of ghes_edac on ghes, make it a proper
module. Use a list to save the probing devices in ghes_probe(), and
defer the
ghes_edac_register() to module_init() of the new ghes_edac module by
iterating over the devices list.

Co-developed-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jia He <redacted>
Fixes: dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in
apci_init()")
Cc: stable@kernel.org

Why is this marked for stable?

The prerequisite patches are needed too. I guess this needs to be
communicated to stable folks somehow by doing

Cc: stable@kernel.org # needs commits X, Y, ...

but I guess the committer needs to do that because only at commit time will X
and Y be known...

So, is there any particular reason why this should be in stable?

Okay, I am fine with removing the stable line if dc4e8c07e9e2 will not be included in
any stable tree branch.

quoted

@@ -1442,7 +1449,9 @@ static int ghes_remove(struct platform_device

*ghes_dev)

 	ghes_fini(ghes);

-	ghes_edac_unregister(ghes);
+	mutex_lock(&ghes_devs_mutex);
+	list_del_rcu(&ghes->elist);

Is that list RCU-protected?

No, I will remove the "rcu" suffix since I use list_add_tail.
 

quoted

+	mutex_unlock(&ghes_devs_mutex);

 	kfree(ghes);

...

quoted

@@ -566,3 +549,35 @@ void ghes_edac_unregister(struct ghes *ghes)
 unlock:
 	mutex_unlock(&ghes_reg_mutex);
 }
+
+static int __init ghes_edac_init(void) {
+	struct ghes *g, *g_tmp;
+
+	if (!IS_ENABLED(CONFIG_X86))
+		force_load = true;

No, this is not how this works.

quoted

+	ghes_devs = ghes_get_devices(force_load);
+	if (!ghes_devs)
+		return -ENODEV;

You simply need to check force_load here.

Okay, hence should I export the *ghes_devs* in ghes?


--
Cheers,
Justin (Jia He)