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<p class="MsoNormal">The framebuffer helper panic notifier is unregistered, in drm_fb_helper_fini(), when kernel_fb_helper_list goes from being non-empty to empty. However, in drm_fb_helper_single_fb_probe(), it's possible for the panic notifier to be registered
without an element being added to this list if a driver's probe function returns 0. Make sure that an attempt to add the panic notifier is made only when adding an element to kernel_fb_helper_list.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Signed-off-by: Frank Binns <frank.binns@imgtec.com><o:p></o:p></p>
<p class="MsoNormal">---<o:p></o:p></p>
<p class="MsoNormal">drivers/gpu/drm/drm_fb_helper.c | 21 ++++++++++-----------<o:p></o:p></p>
<p class="MsoNormal">1 files changed, 10 insertions(+), 11 deletions(-)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c<o:p></o:p></p>
<p class="MsoNormal">index a0d6e89..d3764b3 100644<o:p></o:p></p>
<p class="MsoNormal">--- a/drivers/gpu/drm/drm_fb_helper.c<o:p></o:p></p>
<p class="MsoNormal">+++ b/drivers/gpu/drm/drm_fb_helper.c<o:p></o:p></p>
<p class="MsoNormal">@@ -807,21 +807,20 @@ int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,<o:p></o:p></p>
<p class="MsoNormal"> printk(KERN_INFO "fb%d: %s frame buffer device\n", info->node,<o:p></o:p></p>
<p class="MsoNormal"> info->fix.id);<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">+ /* Switch back to kernel console on panic */<o:p></o:p></p>
<p class="MsoNormal">+ /* multi card linked list maybe */<o:p></o:p></p>
<p class="MsoNormal">+ if (list_empty(&kernel_fb_helper_list)) {<o:p></o:p></p>
<p class="MsoNormal">+ printk(KERN_INFO "drm: registered panic notifier\n");<o:p></o:p></p>
<p class="MsoNormal">+ atomic_notifier_chain_register(&panic_notifier_list,<o:p></o:p></p>
<p class="MsoNormal">+ &paniced);<o:p></o:p></p>
<p class="MsoNormal">+ register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);<o:p></o:p></p>
<p class="MsoNormal">+ }<o:p></o:p></p>
<p class="MsoNormal">+<o:p></o:p></p>
<p class="MsoNormal">+ list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);<o:p></o:p></p>
<p class="MsoNormal"> } else {<o:p></o:p></p>
<p class="MsoNormal"> drm_fb_helper_set_par(info);<o:p></o:p></p>
<p class="MsoNormal"> }<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">- /* Switch back to kernel console on panic */<o:p></o:p></p>
<p class="MsoNormal">- /* multi card linked list maybe */<o:p></o:p></p>
<p class="MsoNormal">- if (list_empty(&kernel_fb_helper_list)) {<o:p></o:p></p>
<p class="MsoNormal">- printk(KERN_INFO "drm: registered panic notifier\n");<o:p></o:p></p>
<p class="MsoNormal">- atomic_notifier_chain_register(&panic_notifier_list,<o:p></o:p></p>
<p class="MsoNormal">- &paniced);<o:p></o:p></p>
<p class="MsoNormal">- register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);<o:p></o:p></p>
<p class="MsoNormal">- }<o:p></o:p></p>
<p class="MsoNormal">- if (new_fb)<o:p></o:p></p>
<p class="MsoNormal">- list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);<o:p></o:p></p>
<p class="MsoNormal">-<o:p></o:p></p>
<p class="MsoNormal"> return 0;<o:p></o:p></p>
<p class="MsoNormal">}<o:p></o:p></p>
<p class="MsoNormal">EXPORT_SYMBOL(drm_fb_helper_single_fb_probe);<o:p></o:p></p>
<p class="MsoNormal">-- <o:p></o:p></p>
<p class="MsoNormal">1.7.5.4<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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