[ 3.8.y.z extended stable ] Patch "radeon kms: fix uninitialised hotplug work usage in" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    radeon kms: fix uninitialised hotplug work usage in

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.10.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 2e4f01803bc66eeac80de132e314c3f9843e1773 Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <sergey.senozhatsky at gmail.com>
Date: Thu, 29 Aug 2013 12:29:35 +0300
Subject: radeon kms: fix uninitialised hotplug work usage in
 r100_irq_process()

commit 27c505ca84e164ec66ad55dcf3f5befaac83f10a upstream.

Commit a01c34f72e7cd2624570818f579b5ab464f93de2 (radeon kms: do not
flush uninitialized hotplug work) moved work initialisation phase to
the last step of radeon_irq_kms_init(). Meelis Roos reported that this
causes problems on his machine because drm_irq_install() uses hotplug
work on r100.

hotplug work flushed in radeon_irq_kms_fini(), with two possible cases:
-- radeon_irq_kms_fini() call after successful radeon_irq_kms_init()
-- radeon_irq_kms_fini() call after unsuccessful (or not called at all)
   radeon_irq_kms_init()

The latter one causes flush work on uninitialised hotplug work. Move
work initialisation before drm_irq_install(), but keep existing agreement
to flush hotplug work in radeon_irq_kms_fini() only for `irq.installed'
(successful radeon_irq_kms_init()) case.

WARNING: CPU: 0 PID: 243 at kernel/workqueue.c:1378 __queue_work+0x132/0x16d()
Call Trace:
[<c12319b3>] ? dump_stack+0xa/0x13
[<c1022600>] ? warn_slowpath_common+0x75/0x8a
[<c1031010>] ? __queue_work+0x132/0x16d
[<c1031010>] ? __queue_work+0x132/0x16d
[<c102269e>] ? warn_slowpath_null+0x1b/0x1f
[<c1031010>] ? __queue_work+0x132/0x16d
[<c103107b>] ? queue_work_on+0x30/0x40
[<f8aed3f3>] ? r100_irq_process+0x16d/0x1e6 [radeon]
[<f8ae77cf>] ? radeon_driver_irq_preinstall_kms+0xc2/0xc5 [radeon]
[<f8974d77>] ? drm_irq_install+0xb2/0x1ac [drm]
[<f897604d>] ? drm_vblank_init+0x196/0x1d2 [drm]
[<f8ae78d3>] ? radeon_irq_kms_init+0x33/0xc6 [radeon]
[<f8aef35a>] ? r100_startup+0x1a3/0x1d6 [radeon]
[<f8ad77c8>] ? radeon_ttm_init+0x26e/0x287 [radeon]
[<f8aef752>] ? r100_init+0x2b3/0x309 [radeon]
[<c118082e>] ? vga_client_register+0x39/0x40
[<f8ac535f>] ? radeon_device_init+0x54b/0x61b [radeon]
[<f8ac40fd>] ? cail_mc_write+0x13/0x13 [radeon]
[<f8ac6864>] ? radeon_driver_load_kms+0x82/0xda [radeon]
[<f8978bbd>] ? drm_get_pci_dev+0x136/0x22d [drm]
[<f8ac409b>] ? radeon_pci_probe+0x6c/0x86 [radeon]
[<c112acf6>] ? pci_device_probe+0x4c/0x83
[<c11846c7>] ? driver_probe_device+0x80/0x184
[<c112a848>] ? pci_match_id+0x18/0x36
[<c1184837>] ? __driver_attach+0x44/0x5f
[<c11833f4>] ? bus_for_each_dev+0x50/0x5a
[<c118433e>] ? driver_attach+0x14/0x16
[<c11847f3>] ? __device_attach+0x28/0x28
[<c1184045>] ? bus_add_driver+0xd6/0x1bf
[<c1184c22>] ? driver_register+0x78/0xcf
[<f8ba8000>] ? 0xf8ba7fff
[<c10003bf>] ? do_one_initcall+0x8b/0x121
[<c101e668>] ? change_page_attr_clear+0x2e/0x33
[<f8ba8000>] ? 0xf8ba7fff
[<c101e689>] ? set_memory_ro+0x1c/0x20
[<c104de94>] ? set_page_attributes+0x11/0x12
[<c104f6e1>] ? load_module+0x12fa/0x17e8
[<c107483b>] ? map_vm_area+0x22/0x31
[<c104fc36>] ? SyS_init_module+0x67/0x7d
[<c1234245>] ? sysenter_do_call+0x12/0x26

Reported-by: Meelis Roos <mroos at linux.ee>
Tested-by: Meelis Roos <mroos at linux.ee>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky at gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
[ kamal: backport to 3.8 (no reset_work) ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/gpu/drm/radeon/radeon_irq_kms.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c
index 4f3b4d5..ecd62b8 100644
--- a/drivers/gpu/drm/radeon/radeon_irq_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c
@@ -256,16 +256,18 @@ int radeon_irq_kms_init(struct radeon_device *rdev)
 			dev_info(rdev->dev, "radeon: using MSI.\n");
 		}
 	}
+
+	INIT_WORK(&rdev->hotplug_work, radeon_hotplug_work_func);
+	INIT_WORK(&rdev->audio_work, r600_audio_update_hdmi);
+
 	rdev->irq.installed = true;
 	r = drm_irq_install(rdev->ddev);
 	if (r) {
 		rdev->irq.installed = false;
+		flush_work(&rdev->hotplug_work);
 		return r;
 	}

-	INIT_WORK(&rdev->hotplug_work, radeon_hotplug_work_func);
-	INIT_WORK(&rdev->audio_work, r600_audio_update_hdmi);
-
 	DRM_INFO("radeon: irq initialized.\n");
 	return 0;
 }
--
1.8.1.2