Patch "powerpc/pseries: Make RAS IRQ explicitly dependent on DLPAR WQ" has been added to the 4.14-stable tree

From foo@baz Wed Feb 28 16:23:28 CET 2018

This is a note to let you know that I've just added the patch titled

powerpc/pseries: Make RAS IRQ explicitly dependent on DLPAR WQ

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
powerpc-pseries-make-ras-irq-explicitly-dependent-on-dlpar-wq.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From foo@baz Wed Feb 28 16:23:28 CET 2018
From: Michael Ellerman <[email protected]>
Date: Mon, 8 Jan 2018 14:54:32 +1100
Subject: powerpc/pseries: Make RAS IRQ explicitly dependent on DLPAR WQ

From: Michael Ellerman <[email protected]>

[ Upstream commit e2d5915293ffdff977ddcfc12b817b08c53ffa7a ]

The hotplug code uses its own workqueue to handle IRQ requests (pseries_hp_wq), however that workqueue is initialized after init_ras_IRQ(). That can lead to a kernel panic if any hotplug interrupts fire after init_ras_IRQ() but before pseries_hp_wq is initialised. eg:

UDP-Lite hash table entries: 2048 (order: 0, 65536 bytes)
NET: Registered protocol family 1
Unpacking initramfs...
(qemu) object_add memory-backend-ram,id=mem1,size=10G (qemu) device_add pc-dimm,id=dimm1,memdev=mem1

  Unable to handle kernel paging request for data at address 0xf94d03007c421378
  Faulting instruction address: 0xc00000000012d744
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in:
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc2-ziviani+ #26
  task:         (ptrval) task.stack:         (ptrval)
  NIP:  c00000000012d744 LR: c00000000012d744 CTR: 0000000000000000
  REGS:         (ptrval) TRAP: 0380   Not tainted  (4.15.0-rc2-ziviani+)
  MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 28088042  XER: 20040000
  CFAR: c00000000012d3c4 SOFTE: 0
  ...
  NIP [c00000000012d744] __queue_work+0xd4/0x5c0
  LR [c00000000012d744] __queue_work+0xd4/0x5c0
  Call Trace:
  [c0000000fffefb90] [c00000000012d744] __queue_work+0xd4/0x5c0 (unreliable)
  [c0000000fffefc70] [c00000000012dce4] queue_work_on+0xb4/0xf0

This commit makes the RAS IRQ registration explicitly dependent on the creation of the pseries_hp_wq.

Reported-by Min Deng <[email protected]>

Reported-by Daniel Henrique Barboza <[email protected]>

Tested-by Jose Ricardo Ziviani <[email protected]>

Signed-off-by Michael Ellerman <[email protected]>

Reviewed-by David Gibson <[email protected]>

Signed-off-by Sasha Levin <[email protected]>

Signed-off-by Greg Kroah-Hartman <[email protected]>

---
 arch/powerpc/platforms/pseries/dlpar.c   |   21 ++++++++++++++++++---
 arch/powerpc/platforms/pseries/pseries.h |    2 ++
 arch/powerpc/platforms/pseries/ras.c     |    3 ++-
 3 files changed, 22 insertions(+), 4 deletions(-)

arch/powerpc/platforms/pseries/dlpar.c +18 -3

@@ -586,11 +586,26 @@ static ssize_t dlpar_show(struct class *
 
 static CLASS_ATTR_RW(dlpar);
 
-static int __init pseries_dlpar_init(void)
+int __init dlpar_workqueue_init(void)
 {
+	if (pseries_hp_wq)
+		return 0;
+
 	pseries_hp_wq = alloc_workqueue("pseries hotplug workqueue",
-					WQ_UNBOUND, 1);
+			WQ_UNBOUND, 1);
+
+	return pseries_hp_wq ? 0 : -ENOMEM;
+}
+
+static int __init dlpar_sysfs_init(void)
+{
+	int rc;
+
+	rc = dlpar_workqueue_init();
+	if (rc)
+		return rc;
+
 	return sysfs_create_file(kernel_kobj, &class_attr_dlpar.attr);
 }
-machine_device_initcall(pseries, pseries_dlpar_init);
+machine_device_initcall(pseries, dlpar_sysfs_init);
 

arch/powerpc/platforms/pseries/pseries.h +2 -0

@@ -98,4 +98,6 @@ static inline unsigned long cmo_get_page
 	return CMO_PageSize;
 }
 
+int dlpar_workqueue_init(void);
+
 #endif /* _PSERIES_PSERIES_H */

arch/powerpc/platforms/pseries/ras.c +2 -1

@@ -69,7 +69,8 @@ static int __init init_ras_IRQ(void)
 	/* Hotplug Events */
 	np = of_find_node_by_path("/event-sources/hot-plug-events");
 	if (np != NULL) {
-		request_event_sources_irqs(np, ras_hotplug_interrupt,
+		if (dlpar_workqueue_init() == 0)
+			request_event_sources_irqs(np, ras_hotplug_interrupt,
 					   "RAS_HOTPLUG");
 		of_node_put(np);
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/powerpc-pseries-make-ras-irq-explicitly-dependent-on-dlpar-wq.patch

Quoted 7 lines · <[email protected]> writes:

This is a note to let you know that I've just added the patch titled

powerpc/pseries: Make RAS IRQ explicitly dependent on DLPAR WQ

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

Quoted 6 lines

The filename of the patch is:
powerpc-pseries-make-ras-irq-explicitly-dependent-on-dlpar-wq.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Did someone request this one?

I didn't Cc it to stable because I wasn't confident of the testing it'd had, and in fact we found another related bug recently.

So if you take this you probably also want:

c9dccf1d074a ("powerpc/pseries: Enable RAS hotplug events later")

But note that commit is only ~2-3 weeks old, so again I can't vouch 100% for it's bullet-proof-ness.

Quoted 13 lines · Michael Ellerman

Quoted 11 lines · <[email protected]> writes:

This is a note to let you know that I've just added the patch titled

powerpc/pseries: Make RAS IRQ explicitly dependent on DLPAR WQ

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
powerpc-pseries-make-ras-irq-explicitly-dependent-on-dlpar-wq.patch
and it can be found in the queue-4.14 subdirectory.

Quoted 4 lines

Quoted 2 lines

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Did someone request this one?

Sasha did (his email now fixed...)

Quoted 5 lines

I didn't Cc it to stable because I wasn't confident of the testing it'd had, and in fact we found another related bug recently.

So if you take this you probably also want:

Quoted 5 lines

c9dccf1d074a ("powerpc/pseries: Enable RAS hotplug events later")

But note that commit is only ~2-3 weeks old, so again I can't vouch 100% for it's bullet-proof-ness.

So do you want me to drop this one, or take both? I can do either, it's up to you...

Quoted 14 lines · Greg KH

Quoted 13 lines · Michael Ellerman

Quoted 11 lines · <[email protected]> writes:

This is a note to let you know that I've just added the patch titled

powerpc/pseries: Make RAS IRQ explicitly dependent on DLPAR WQ

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
powerpc-pseries-make-ras-irq-explicitly-dependent-on-dlpar-wq.patch
and it can be found in the queue-4.14 subdirectory.

Quoted 6 lines

Quoted 4 lines

Quoted 2 lines

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Did someone request this one?

Sasha did (his email now fixed...)

Ah ok.

Quoted 8 lines

Quoted 8 lines

I didn't Cc it to stable because I wasn't confident of the testing it'd had, and in fact we found another related bug recently.

So if you take this you probably also want:

c9dccf1d074a ("powerpc/pseries: Enable RAS hotplug events later")

Quoted 5 lines

Quoted 2 lines

But note that commit is only ~2-3 weeks old, so again I can't vouch 100% for it's bullet-proof-ness.

So do you want me to drop this one, or take both? I can do either, it's up to you...

OK, take both then please.