| Message ID | 20230207143337.2126678-1-jani.nikula@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: Disable dynamic debug as broken | expand |
On Tue, Feb 07, 2023 at 04:33:37PM +0200, Jani Nikula wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > CONFIG_DRM_USE_DYNAMIC_DEBUG breaks debug prints for (at least modular) > drm drivers. The debug prints can be reinstated by manually frobbing > /sys/module/drm/parameters/debug after the fact, but at that point the > damage is done and all debugs from driver probe are lost. This makes > drivers totally undebuggable. > > There's a more complete fix in progress [1], with further details, but > we need this fixed in stable kernels. Mark the feature as broken and > disable it by default, with hopes distros follow suit and disable it as > well. > > [1] https://lore.kernel.org/r/20230125203743.564009-1-jim.cromie@gmail.com > > Fixes: 84ec67288c10 ("drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro") > Cc: Jim Cromie <jim.cromie@gmail.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > Cc: Maxime Ripard <mripard@kernel.org> > Cc: Thomas Zimmermann <tzimmermann@suse.de> > Cc: David Airlie <airlied@gmail.com> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: dri-devel@lists.freedesktop.org > Cc: <stable@vger.kernel.org> # v6.1+ > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > Signed-off-by: Jani Nikula <jani.nikula@intel.com> > --- > drivers/gpu/drm/Kconfig | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index f42d4c6a19f2..dc0f94f02a82 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -52,7 +52,8 @@ config DRM_DEBUG_MM > > config DRM_USE_DYNAMIC_DEBUG > bool "use dynamic debug to implement drm.debug" > - default y > + default n > + depends on BROKEN > depends on DRM > depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE > depends on JUMP_LABEL Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On Tue, 07 Feb 2023, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Tue, Feb 07, 2023 at 04:33:37PM +0200, Jani Nikula wrote: >> From: Ville Syrjälä <ville.syrjala@linux.intel.com> >> >> CONFIG_DRM_USE_DYNAMIC_DEBUG breaks debug prints for (at least modular) >> drm drivers. The debug prints can be reinstated by manually frobbing >> /sys/module/drm/parameters/debug after the fact, but at that point the >> damage is done and all debugs from driver probe are lost. This makes >> drivers totally undebuggable. >> >> There's a more complete fix in progress [1], with further details, but >> we need this fixed in stable kernels. Mark the feature as broken and >> disable it by default, with hopes distros follow suit and disable it as >> well. >> >> [1] https://lore.kernel.org/r/20230125203743.564009-1-jim.cromie@gmail.com >> >> Fixes: 84ec67288c10 ("drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro") >> Cc: Jim Cromie <jim.cromie@gmail.com> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> >> Cc: Maxime Ripard <mripard@kernel.org> >> Cc: Thomas Zimmermann <tzimmermann@suse.de> >> Cc: David Airlie <airlied@gmail.com> >> Cc: Daniel Vetter <daniel@ffwll.ch> >> Cc: dri-devel@lists.freedesktop.org >> Cc: <stable@vger.kernel.org> # v6.1+ >> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> >> Signed-off-by: Jani Nikula <jani.nikula@intel.com> >> --- >> drivers/gpu/drm/Kconfig | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig >> index f42d4c6a19f2..dc0f94f02a82 100644 >> --- a/drivers/gpu/drm/Kconfig >> +++ b/drivers/gpu/drm/Kconfig >> @@ -52,7 +52,8 @@ config DRM_DEBUG_MM >> >> config DRM_USE_DYNAMIC_DEBUG >> bool "use dynamic debug to implement drm.debug" >> - default y >> + default n >> + depends on BROKEN >> depends on DRM >> depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE >> depends on JUMP_LABEL > > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Thanks Greg, any more acks from anyone? Maxime, since there's going to be an -rc8, I suggest taking this via drm-misc-fixes. Is that okay with you? (You're doing drm-misc-fixes this round, right?) BR, Jani.
On Tue, Feb 7, 2023 at 10:21 AM Jani Nikula <jani.nikula@intel.com> wrote: > > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > CONFIG_DRM_USE_DYNAMIC_DEBUG breaks debug prints for (at least modular) > drm drivers. The debug prints can be reinstated by manually frobbing > /sys/module/drm/parameters/debug after the fact, but at that point the > damage is done and all debugs from driver probe are lost. This makes > drivers totally undebuggable. > > There's a more complete fix in progress [1], with further details, but > we need this fixed in stable kernels. Mark the feature as broken and > disable it by default, with hopes distros follow suit and disable it as > well. > > [1] https://lore.kernel.org/r/20230125203743.564009-1-jim.cromie@gmail.com > > Fixes: 84ec67288c10 ("drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro") > Cc: Jim Cromie <jim.cromie@gmail.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > Cc: Maxime Ripard <mripard@kernel.org> > Cc: Thomas Zimmermann <tzimmermann@suse.de> > Cc: David Airlie <airlied@gmail.com> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: dri-devel@lists.freedesktop.org > Cc: <stable@vger.kernel.org> # v6.1+ > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > Signed-off-by: Jani Nikula <jani.nikula@intel.com> > --- > drivers/gpu/drm/Kconfig | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index f42d4c6a19f2..dc0f94f02a82 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -52,7 +52,8 @@ config DRM_DEBUG_MM > > config DRM_USE_DYNAMIC_DEBUG > bool "use dynamic debug to implement drm.debug" > - default y > + default n > + depends on BROKEN > depends on DRM > depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE > depends on JUMP_LABEL > -- > 2.34.1 > Acked-by: Jim Cromie <jim.cromie@gmail.com>
On Fri, 10 Feb 2023, Jani Nikula <jani.nikula@intel.com> wrote: > On Tue, 07 Feb 2023, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: >> On Tue, Feb 07, 2023 at 04:33:37PM +0200, Jani Nikula wrote: >>> From: Ville Syrjälä <ville.syrjala@linux.intel.com> >>> >>> CONFIG_DRM_USE_DYNAMIC_DEBUG breaks debug prints for (at least modular) >>> drm drivers. The debug prints can be reinstated by manually frobbing >>> /sys/module/drm/parameters/debug after the fact, but at that point the >>> damage is done and all debugs from driver probe are lost. This makes >>> drivers totally undebuggable. >>> >>> There's a more complete fix in progress [1], with further details, but >>> we need this fixed in stable kernels. Mark the feature as broken and >>> disable it by default, with hopes distros follow suit and disable it as >>> well. >>> >>> [1] https://lore.kernel.org/r/20230125203743.564009-1-jim.cromie@gmail.com >>> >>> Fixes: 84ec67288c10 ("drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro") >>> Cc: Jim Cromie <jim.cromie@gmail.com> >>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >>> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> >>> Cc: Maxime Ripard <mripard@kernel.org> >>> Cc: Thomas Zimmermann <tzimmermann@suse.de> >>> Cc: David Airlie <airlied@gmail.com> >>> Cc: Daniel Vetter <daniel@ffwll.ch> >>> Cc: dri-devel@lists.freedesktop.org >>> Cc: <stable@vger.kernel.org> # v6.1+ >>> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> >>> Signed-off-by: Jani Nikula <jani.nikula@intel.com> >>> --- >>> drivers/gpu/drm/Kconfig | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig >>> index f42d4c6a19f2..dc0f94f02a82 100644 >>> --- a/drivers/gpu/drm/Kconfig >>> +++ b/drivers/gpu/drm/Kconfig >>> @@ -52,7 +52,8 @@ config DRM_DEBUG_MM >>> >>> config DRM_USE_DYNAMIC_DEBUG >>> bool "use dynamic debug to implement drm.debug" >>> - default y >>> + default n >>> + depends on BROKEN >>> depends on DRM >>> depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE >>> depends on JUMP_LABEL >> >> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Thanks Greg, any more acks from anyone? > > Maxime, since there's going to be an -rc8, I suggest taking this via > drm-misc-fixes. Is that okay with you? (You're doing drm-misc-fixes this > round, right?) Pushed to drm-misc-fixes with Maxime's IRC ack and Jim's ack elsewhere in the thread. Thanks. BR, Jani. > > BR, > Jani.
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index f42d4c6a19f2..dc0f94f02a82 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -52,7 +52,8 @@ config DRM_DEBUG_MM config DRM_USE_DYNAMIC_DEBUG bool "use dynamic debug to implement drm.debug" - default y + default n + depends on BROKEN depends on DRM depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE depends on JUMP_LABEL