Messages in this thread | | | Date | Fri, 25 Mar 2022 18:43:31 +0800 | Subject | Re: [PATCH] thermal: devfreq_cooling: use local ops instead of global ops | From | Kant Fan <> |
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On 14/03/2022 21:41, Lukasz Luba wrote: > Hi Kant, > > On 3/12/22 04:59, Kant Fan wrote: >> Fix access illegal address problem in following condition: >> There are muti devfreq cooling devices in system, some of them has >> em model but other does not, energy model ops such as state2power will >> append to global devfreq_cooling_ops when the cooling device with >> em model register. It makes the cooling device without em model >> also use devfreq_cooling_ops after appending when register later by >> of_devfreq_cooling_register_power() or of_devfreq_cooling_register(). >> >> IPA governor regards the cooling devices without em model as a power >> actor >> because they also have energy model ops, and will access illegal address >> at dfc->em_pd when execute cdev->ops->get_requested_power, >> cdev->ops->state2power or cdev->ops->power2state. >> >> Signed-off-by: Kant Fan <kant@allwinnertech.com> > > Thank you for finding this issue. This was also an issue since the > beginning of that code. The modified global ops after first registration > which went through, was also previously there. Thus, we would need two > different patches for stable kernels. > > For this one, please add the tag: > Fixes: 615510fe13bd2 ("thermal: devfreq_cooling: remove old power model > and use EM") > > This patch would also go via stable tree for kernels v5.11+ > Please read the process how to send a patch which will be merged to the > stable tree. > > There will be a need to create another patch(es) for stable kernels with > Fixes: a76caf55e5b35 ("thermal: Add devfreq cooling") > In those kernels also the global ops is modified and might not support > properly many cooling devices. It's present in other stable kernels: > v5.10 and older > >> --- >> drivers/thermal/devfreq_cooling.c | 25 ++++++++++++++++++------- >> 1 file changed, 18 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/thermal/devfreq_cooling.c >> b/drivers/thermal/devfreq_cooling.c >> index 4310cb342a9f..d38a80adec73 100644 >> --- a/drivers/thermal/devfreq_cooling.c >> +++ b/drivers/thermal/devfreq_cooling.c >> @@ -358,21 +358,28 @@ of_devfreq_cooling_register_power(struct >> device_node *np, struct devfreq *df, >> struct thermal_cooling_device *cdev; >> struct device *dev = df->dev.parent; >> struct devfreq_cooling_device *dfc; >> + struct thermal_cooling_device_ops *ops; >> char *name; >> int err, num_opps; >> - dfc = kzalloc(sizeof(*dfc), GFP_KERNEL); >> - if (!dfc) >> + ops = kmemdup(&devfreq_cooling_ops, sizeof(*ops), GFP_KERNEL); >> + if (!ops) >> return ERR_PTR(-ENOMEM); >> + dfc = kzalloc(sizeof(*dfc), GFP_KERNEL); >> + if (!dfc) { >> + err = -ENOMEM; >> + goto free_ops; >> + } >> + >> dfc->devfreq = df; >> dfc->em_pd = em_pd_get(dev); >> if (dfc->em_pd) { >> - devfreq_cooling_ops.get_requested_power = >> + ops->get_requested_power = >> devfreq_cooling_get_requested_power; >> - devfreq_cooling_ops.state2power = devfreq_cooling_state2power; >> - devfreq_cooling_ops.power2state = devfreq_cooling_power2state; >> + ops->state2power = devfreq_cooling_state2power; >> + ops->power2state = devfreq_cooling_power2state; >> dfc->power_ops = dfc_power; >> @@ -407,8 +414,7 @@ of_devfreq_cooling_register_power(struct >> device_node *np, struct devfreq *df, >> if (!name) >> goto remove_qos_req; >> - cdev = thermal_of_cooling_device_register(np, name, dfc, >> - &devfreq_cooling_ops); >> + cdev = thermal_of_cooling_device_register(np, name, dfc, ops); >> kfree(name); >> if (IS_ERR(cdev)) { >> @@ -429,6 +435,8 @@ of_devfreq_cooling_register_power(struct >> device_node *np, struct devfreq *df, >> kfree(dfc->freq_table); >> free_dfc: >> kfree(dfc); >> +free_ops: >> + kfree(ops); >> return ERR_PTR(err); >> } >> @@ -510,11 +518,13 @@ EXPORT_SYMBOL_GPL(devfreq_cooling_em_register); >> void devfreq_cooling_unregister(struct thermal_cooling_device *cdev) >> { >> struct devfreq_cooling_device *dfc; >> + const struct thermal_cooling_device_ops *ops; >> struct device *dev; >> if (IS_ERR_OR_NULL(cdev)) >> return; >> + ops = cdev->ops; >> dfc = cdev->devdata; >> dev = dfc->devfreq->dev.parent; >> @@ -525,5 +535,6 @@ void devfreq_cooling_unregister(struct >> thermal_cooling_device *cdev) >> kfree(dfc->freq_table); >> kfree(dfc); >> + kfree(ops); >> } >> EXPORT_SYMBOL_GPL(devfreq_cooling_unregister); > > The fix looks good.
Hi Lukasz, Thanks for your advice. According to that, I made two separate patches for mainline and the stable trees: The first patch (patchwork.kernel.org: Message ID: 20220325073030.91919-1-kant@allwinnertech.com) is for mainline. I added the 'fix' tag and 'Cc: stable@vger.kernel.org # 5.13+' to remind which stable trees should be back-ported. The second patch (patchwork.kernel.org: Message ID: 20220325094436.101419-1-kant@allwinnertech.com) is for stable tree v5.10 and older. I added an upstream commit ID to indicate where the patch comes from. I also added 'Cc: stable@vger.kernel.org # 4.4+' to remind which stable trees should be back-ported. Please check if they are correct. Thank you.
Kant Fan
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