[Arm-dev] [PATCH 3/3] Fix lockdep warning when request PCC channel in mailbox PCC driver
Duc Dang
dhdang at apm.com
Fri Nov 18 01:30:31 UTC 2016
The fix was already reviewed by Prashant and accepted by Rafael:
https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/commit/?h=bleeding-edge&id=6ca595a70bc46e1a0eea3ee0681360f41555bfd9
Signed-off-by: Duc Dang <dhdang at apm.com>
---
...-Fix-lockdep-warning-when-request-PCC-cha.patch | 120 +++++++++++++++++++++
SPECS/kernel-aarch64.spec | 3 +
2 files changed, 123 insertions(+)
create mode 100644 SOURCES/1028-mailbox-PCC-Fix-lockdep-warning-when-request-PCC-cha.patch
diff --git a/SOURCES/1028-mailbox-PCC-Fix-lockdep-warning-when-request-PCC-cha.patch b/SOURCES/1028-mailbox-PCC-Fix-lockdep-warning-when-request-PCC-cha.patch
new file mode 100644
index 0000000..9276390
--- /dev/null
+++ b/SOURCES/1028-mailbox-PCC-Fix-lockdep-warning-when-request-PCC-cha.patch
@@ -0,0 +1,120 @@
+From ba77f6beff28859afd0b57282012183684647d8a Mon Sep 17 00:00:00 2001
+From: Hoan Tran <hotran at apm.com>
+Date: Mon, 14 Nov 2016 11:19:02 -0800
+Subject: [PATCH] mailbox: PCC: Fix lockdep warning when request PCC channel
+
+This patch fixes the lockdep warning below
+
+DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
+------------[ cut here ]------------
+WARNING: CPU: 1 PID: 1 at linux-next/kernel/locking/lockdep.c:2876 lockdep_trace_alloc+0xe0/0xf0
+ Modules linked in:
+
+ CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.8.0-11756-g86c5152 #46
+...
+ Call trace:
+ Exception stack(0xffff8007da837890 to 0xffff8007da8379c0)
+ 7880: ffff8007da834000 0001000000000000
+ 78a0: ffff8007da837a70 ffff0000081111a0 00000000600000c5 000000000000003d
+ 78c0: 9374bc6a7f3c7832 0000000000381878 ffff000009db7ab8 000000000000002f
+ 78e0: ffff00000811aabc ffff000008be2548 ffff8007da837990 ffff00000811adf8
+ 7900: ffff8007da834000 00000000024080c0 00000000000000c0 ffff000009021000
+ 7920: 0000000000000000 0000000000000000 ffff000008c8f7c8 ffff8007da579810
+ 7940: 000000000000002f ffff8007da858000 0000000000000000 0000000000000001
+ 7960: 0000000000000001 0000000000000000 ffff00000811a468 0000000000000002
+ 7980: 656c62617369645f 0000000000038187 00000000000000ee ffff8007da837850
+ 79a0: ffff000009db50c0 ffff000009db569d 0000000000000006 ffff000089db568f
+ [<ffff0000081111a0>] lockdep_trace_alloc+0xe0/0xf0
+ [<ffff0000081f4950>] __kmalloc_track_caller+0x50/0x250
+ [<ffff00000857c088>] devres_alloc_node+0x28/0x60
+ [<ffff0000081220e0>] devm_request_threaded_irq+0x50/0xe0
+ [<ffff0000087e6220>] pcc_mbox_request_channel+0x110/0x170
+ [<ffff0000084b2660>] acpi_cppc_processor_probe+0x264/0x414
+ [<ffff0000084ae9f4>] __acpi_processor_start+0x28/0xa0
+ [<ffff0000084aeab0>] acpi_processor_start+0x44/0x54
+ [<ffff00000857897c>] driver_probe_device+0x1fc/0x2b0
+ [<ffff000008578ae4>] __driver_attach+0xb4/0xc0
+ [<ffff00000857683c>] bus_for_each_dev+0x5c/0xa0
+ [<ffff000008578110>] driver_attach+0x20/0x30
+ [<ffff000008577c20>] bus_add_driver+0x110/0x230
+ [<ffff000008579320>] driver_register+0x60/0x100
+ [<ffff000008d478b8>] acpi_processor_driver_init+0x2c/0xb0
+ [<ffff000008083168>] do_one_initcall+0x38/0x130
+ [<ffff000008d20d6c>] kernel_init_freeable+0x210/0x2b4
+ [<ffff000008945d90>] kernel_init+0x10/0x110
+ [<ffff000008082e80>] ret_from_fork+0x10/0x50
+
+It's because the spinlock inside pcc_mbox_request_channel() is
+kept too long. This patch releases spinlock before request_irq()
+and free_irq() to fix this issue as spinlock is only needed to
+protect the channel data.
+
+Signed-off-by: Hoan Tran <hotran at apm.com>
+Reviewed-by: Prashanth Prakash <pprakash at codeaurora.org>
+Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
+---
+ drivers/mailbox/pcc.c | 13 +++++++------
+ 1 file changed, 7 insertions(+), 6 deletions(-)
+
+diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
+index c98bd94..fb594ed 100644
+--- a/drivers/mailbox/pcc.c
++++ b/drivers/mailbox/pcc.c
+@@ -65,6 +65,7 @@
+ #include <linux/mailbox_controller.h>
+ #include <linux/mailbox_client.h>
+ #include <linux/io-64-nonatomic-lo-hi.h>
++#include <acpi/pcc.h>
+
+ #include "mailbox.h"
+
+@@ -267,6 +268,8 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
+ if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
+ chan->txdone_method |= TXDONE_BY_ACK;
+
++ spin_unlock_irqrestore(&chan->lock, flags);
++
+ if (pcc_doorbell_irq[subspace_id] > 0) {
+ int rc;
+
+@@ -275,12 +278,11 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
+ if (unlikely(rc)) {
+ dev_err(dev, "failed to register PCC interrupt %d\n",
+ pcc_doorbell_irq[subspace_id]);
++ pcc_mbox_free_channel(chan);
+ chan = ERR_PTR(rc);
+ }
+ }
+
+- spin_unlock_irqrestore(&chan->lock, flags);
+-
+ return chan;
+ }
+ EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
+@@ -304,20 +306,19 @@ void pcc_mbox_free_channel(struct mbox_chan *chan)
+ return;
+ }
+
++ if (pcc_doorbell_irq[id] > 0)
++ devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
++
+ spin_lock_irqsave(&chan->lock, flags);
+ chan->cl = NULL;
+ chan->active_req = NULL;
+ if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
+ chan->txdone_method = TXDONE_BY_POLL;
+
+- if (pcc_doorbell_irq[id] > 0)
+- devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
+-
+ spin_unlock_irqrestore(&chan->lock, flags);
+ }
+ EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
+
+-
+ /**
+ * pcc_send_data - Called from Mailbox Controller code. Used
+ * here only to ring the channel doorbell. The PCC client
+--
+1.8.3.1
+
diff --git a/SPECS/kernel-aarch64.spec b/SPECS/kernel-aarch64.spec
index 6e7950b..b9596d5 100644
--- a/SPECS/kernel-aarch64.spec
+++ b/SPECS/kernel-aarch64.spec
@@ -352,6 +352,7 @@ Patch1024: 1024-arm64-efi-esrt-add-missing-call-to-efi_esrt_init.patch
Patch1025: 1025-efi-esrt-Don-t-preformat-name.patch
Patch1026: 1026-efi-esrt-Use-efi_mem_reserve-and-avoid-a-kmalloc.patch
Patch1027: 1027-efi-esrt-Use-memremap-not-ioremap-to-access-ESRT-tab.patch
+Patch1028: 1028-mailbox-PCC-Fix-lockdep-warning-when-request-PCC-cha.patch
# QDF2400 Patches
Patch4000: 4000-arm64-Define-Qualcomm-Technologies-ARMv8-CPU.patch
@@ -714,6 +715,7 @@ git am %{PATCH1024}
git am %{PATCH1025}
git am %{PATCH1026}
git am %{PATCH1027}
+git am %{PATCH1028}
# Apply QDF2400 patches
git am %{PATCH4000}
@@ -1493,6 +1495,7 @@ fi
%changelog
* Thu Nov 17 2016 Duc Dang <dhdang at apm.com> [4.5.0-18.el7]
+- Integrate upstream fix for a lockdep warning when request PCC channel
- Backport upstream patches to support fwupdate
- Integrate upstream patch to add interrupt support for X-Gene Standby GPIO
--
1.8.3.1
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