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Message-ID: <20100913215850.GA2176@del.dom.local>
Date: Mon, 13 Sep 2010 23:58:50 +0200
From: Jarek Poplawski <jarkao2@...il.com>
To: linux-fbdev@...r.kernel.org
Cc: Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org
Subject: [PATCH] fbcon: fix lockdep warning from fbcon_deinit()
Hi,
Here is a warning and a patch proposal below.
Jarek P.
[ 13.334829] i915 0000:00:02.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
[ 13.350597] i915 0000:00:02.0: setting latency timer to 64
[ 13.382380] [drm] set up 7M of stolen space
[ 13.420049] vgaarb: device changed decodes: PCI:0000:00:02.0,olddecodes=io+mem,decodes=io+mem:owns=io+mem
[ 13.422851] [drm] initialized overlay support
[ 13.655021] checking generic (f0000000 180000) vs hw (f0000000 8000000)
[ 13.655055] fb: conflicting fb hw usage inteldrmfb vs VESA VGA - removing generic driver
[ 13.657164] INFO: trying to register non-static key.
[ 13.657169] the code is fine but needs lockdep annotation.
[ 13.657171] turning off the locking correctness validator.
[ 13.657177] Pid: 622, comm: modprobe Not tainted 2.6.36-rc3c #8
[ 13.657180] Call Trace:
[ 13.657194] [<c13002c8>] ? printk+0x18/0x20
[ 13.657202] [<c1056cf6>] register_lock_class+0x336/0x350
[ 13.657208] [<c1058bf9>] __lock_acquire+0x449/0x1180
[ 13.657215] [<c1059997>] lock_acquire+0x67/0x80
[ 13.657222] [<c1042bf1>] ? __cancel_work_timer+0x51/0x230
[ 13.657227] [<c1042c23>] __cancel_work_timer+0x83/0x230
[ 13.657231] [<c1042bf1>] ? __cancel_work_timer+0x51/0x230
[ 13.657236] [<c10582b2>] ? mark_held_locks+0x62/0x80
[ 13.657243] [<c10b3a2f>] ? kfree+0x7f/0xe0
[ 13.657248] [<c105853c>] ? trace_hardirqs_on_caller+0x11c/0x160
[ 13.657253] [<c105858b>] ? trace_hardirqs_on+0xb/0x10
[ 13.657259] [<c117f4cd>] ? fbcon_deinit+0x16d/0x1e0
[ 13.657263] [<c117f4cd>] ? fbcon_deinit+0x16d/0x1e0
[ 13.657268] [<c1042dea>] cancel_work_sync+0xa/0x10
[ 13.657272] [<c117f444>] fbcon_deinit+0xe4/0x1e0
[ 13.657280] [<c11cdf5c>] bind_con_driver+0x1ac/0x3d0
[ 13.657286] [<c1027e8b>] ? get_parent_ip+0xb/0x40
[ 13.657292] [<c102efe1>] ? release_console_sem+0x1d1/0x210
[ 13.657297] [<c11ce383>] unbind_con_driver+0x1b3/0x1f0
[ 13.657303] [<c1180fa5>] fbcon_event_notify+0x575/0x920
[ 13.657308] [<c105858b>] ? trace_hardirqs_on+0xb/0x10
[ 13.657314] [<c10582b2>] ? mark_held_locks+0x62/0x80
[ 13.657320] [<c1303370>] ? restore_all_notrace+0x0/0x18
[ 13.657324] [<c105853c>] ? trace_hardirqs_on_caller+0x11c/0x160
[ 13.657331] [<c1154f98>] ? trace_hardirqs_on_thunk+0xc/0x10
[ 13.657339] [<c104c86a>] ? __blocking_notifier_call_chain+0x2a/0x60
[ 13.657344] [<c104c4bd>] notifier_call_chain+0x2d/0x70
[ 13.657349] [<c104c884>] __blocking_notifier_call_chain+0x44/0x60
[ 13.657354] [<c104c8ba>] blocking_notifier_call_chain+0x1a/0x20
[ 13.657360] [<c11727c1>] fb_notifier_call_chain+0x11/0x20
[ 13.657364] [<c1173648>] unregister_framebuffer+0x58/0xf0
[ 13.657369] [<c1173855>] remove_conflicting_framebuffers+0x175/0x1a0
[ 13.657375] [<c105858b>] ? trace_hardirqs_on+0xb/0x10
[ 13.657380] [<c11738fd>] register_framebuffer+0x7d/0x270
[ 13.657386] [<c105858b>] ? trace_hardirqs_on+0xb/0x10
[ 13.657396] [<d0451818>] ? drm_setup_crtcs+0x3a8/0x640 [drm_kms_helper]
[ 13.657402] [<d0451efb>] drm_fb_helper_single_fb_probe+0x26b/0x2d0 [drm_kms_helper]
[ 13.657409] [<d04521fb>] drm_fb_helper_initial_config+0x29b/0x610 [drm_kms_helper]
[ 13.657417] [<c10b44e9>] ? kmem_cache_alloc+0x69/0xb0
[ 13.657423] [<d04525af>] ? drm_fb_helper_single_add_all_connectors+0x3f/0xc0 [drm_kms_helper]
[ 13.657456] [<d060fd0f>] intel_fbdev_init+0x6f/0x90 [i915]
[ 13.657473] [<d05ed79d>] i915_driver_load+0x113d/0x13b0 [i915]
[ 13.657492] [<d05ec640>] ? i915_vga_set_decode+0x0/0x20 [i915]
[ 13.657519] [<d03ebf69>] drm_get_pci_dev+0x149/0x250 [drm]
[ 13.657527] [<c102807b>] ? sub_preempt_count+0x7b/0xb0
[ 13.657546] [<d0617308>] i915_pci_probe+0xd/0x18d [i915]
[ 13.657552] [<c11656ae>] local_pci_probe+0xe/0x10
[ 13.657558] [<c1165f50>] pci_device_probe+0x60/0x80
[ 13.657565] [<c11d681c>] driver_probe_device+0x6c/0x190
[ 13.657570] [<c11d69c1>] __driver_attach+0x81/0x90
[ 13.657576] [<c11d609b>] bus_for_each_dev+0x5b/0x80
[ 13.657580] [<c1165e90>] ? pci_device_remove+0x0/0x40
[ 13.657585] [<c11d66b9>] driver_attach+0x19/0x20
[ 13.657589] [<c11d6940>] ? __driver_attach+0x0/0x90
[ 13.657594] [<c11d59e7>] bus_add_driver+0x1a7/0x270
[ 13.657599] [<c1165e90>] ? pci_device_remove+0x0/0x40
[ 13.657604] [<c11d6c45>] driver_register+0x75/0x160
[ 13.657620] [<d0482000>] ? i915_init+0x0/0x93 [i915]
[ 13.657625] [<c11661a4>] __pci_register_driver+0x54/0xc0
[ 13.657644] [<d0482000>] ? i915_init+0x0/0x93 [i915]
[ 13.657657] [<d03ec115>] drm_pci_init+0xa5/0xb0 [drm]
[ 13.657675] [<d0482000>] ? i915_init+0x0/0x93 [i915]
[ 13.657687] [<d03e553f>] drm_init+0x4f/0x70 [drm]
[ 13.657703] [<d048206a>] i915_init+0x6a/0x93 [i915]
[ 13.657710] [<c100111b>] do_one_initcall+0x2b/0x150
[ 13.657714] [<c10a8194>] ? __vunmap+0xa4/0xf0
[ 13.657721] [<c10617ed>] sys_init_module+0x14d/0x18b0
[ 13.657744] [<c130333d>] syscall_call+0x7/0xb
[ 13.657885] Console: switching to colour dummy device 80x25
[ 13.659795] checking generic (a0000 10000) vs hw (f0000000 8000000)
[ 13.659818] fb: conflicting fb hw usage inteldrmfb vs VGA16 VGA - removing generic driver
[ 13.688319] [drm:intel_calculate_wm] *ERROR* Insufficient FIFO for plane, expect flickering: entries required = 51, available = 47.
[ 13.688400] Console: switching to colour frame buffer device 128x48
[ 13.693608] fb0: inteldrmfb frame buffer device
...
------------->
This patch fixes the lockdep warning:
[ 13.657164] INFO: trying to register non-static key.
[ 13.657169] the code is fine but needs lockdep annotation.
[ 13.657171] turning off the locking correctness validator.
[ 13.657177] Pid: 622, comm: modprobe Not tainted 2.6.36-rc3c #8
[ 13.657180] Call Trace:
[ 13.657194] [<c13002c8>] ? printk+0x18/0x20
[ 13.657202] [<c1056cf6>] register_lock_class+0x336/0x350
[ 13.657208] [<c1058bf9>] __lock_acquire+0x449/0x1180
[ 13.657215] [<c1059997>] lock_acquire+0x67/0x80
[ 13.657222] [<c1042bf1>] ? __cancel_work_timer+0x51/0x230
[ 13.657227] [<c1042c23>] __cancel_work_timer+0x83/0x230
[ 13.657231] [<c1042bf1>] ? __cancel_work_timer+0x51/0x230
[ 13.657236] [<c10582b2>] ? mark_held_locks+0x62/0x80
[ 13.657243] [<c10b3a2f>] ? kfree+0x7f/0xe0
[ 13.657248] [<c105853c>] ? trace_hardirqs_on_caller+0x11c/0x160
[ 13.657253] [<c105858b>] ? trace_hardirqs_on+0xb/0x10
[ 13.657259] [<c117f4cd>] ? fbcon_deinit+0x16d/0x1e0
[ 13.657263] [<c117f4cd>] ? fbcon_deinit+0x16d/0x1e0
[ 13.657268] [<c1042dea>] cancel_work_sync+0xa/0x10
[ 13.657272] [<c117f444>] fbcon_deinit+0xe4/0x1e0
...
The warning is caused by trying to cancel an uninitialized work from
fbcon_exit(). Fix it by adding a check for queue.func, similarly to
other places in this code.
Signed-off-by: Jarek Poplawski <jarkao2@...il.com>
---
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 84f8423..7ccc967 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -3508,7 +3508,7 @@ static void fbcon_exit(void)
softback_buf = 0UL;
for (i = 0; i < FB_MAX; i++) {
- int pending;
+ int pending = 0;
mapped = 0;
info = registered_fb[i];
@@ -3516,7 +3516,8 @@ static void fbcon_exit(void)
if (info == NULL)
continue;
- pending = cancel_work_sync(&info->queue);
+ if (info->queue.func)
+ pending = cancel_work_sync(&info->queue);
DPRINTK("fbcon: %s pending work\n", (pending ? "canceled" :
"no"));
--
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