Messages in this thread | | | Date | Wed, 16 Aug 2023 16:07:31 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH v2] cpufreq: cppc: Set fie_disabled to FIE_DISABLED if fails to create kworker_fie |
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On 16-08-23, 09:49, Liao Chang wrote: > The function cppc_freq_invariance_init() may failed to create > kworker_fie, make it more robust by setting fie_disabled to FIE_DISBALED > to prevent an invalid pointer dereference in kthread_destroy_worker(), > which called from cppc_freq_invariance_exit(). > > Link: https://lore.kernel.org/all/20230816034630.a4hvsj373q6aslk3@vireshk-i7/ > > Signed-off-by: Liao Chang <liaochang1@huawei.com> > --- > drivers/cpufreq/cppc_cpufreq.c | 28 ++++++++++++++++------------ > 1 file changed, 16 insertions(+), 12 deletions(-) > > diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c > index 022e3555407c..bff4cde06083 100644 > --- a/drivers/cpufreq/cppc_cpufreq.c > +++ b/drivers/cpufreq/cppc_cpufreq.c > @@ -220,6 +220,15 @@ static void cppc_cpufreq_cpu_fie_exit(struct cpufreq_policy *policy) > } > } > > +static void cppc_freq_invariance_exit(void) > +{ > + if (fie_disabled) > + return; > + > + kthread_destroy_worker(kworker_fie); > + kworker_fie = NULL; > +} > + > static void __init cppc_freq_invariance_init(void) > { > struct sched_attr attr = { > @@ -249,27 +258,22 @@ static void __init cppc_freq_invariance_init(void) > return; > > kworker_fie = kthread_create_worker(0, "cppc_fie"); > - if (IS_ERR(kworker_fie)) > + if (IS_ERR(kworker_fie)) { > + pr_warn("%s: failed to create kworker_fie: %ld\n", __func__, > + PTR_ERR(kworker_fie)); > + fie_disabled = FIE_DISABLED; > return; > + } > > ret = sched_setattr_nocheck(kworker_fie->task, &attr); > if (ret) { > pr_warn("%s: failed to set SCHED_DEADLINE: %d\n", __func__, > ret); > - kthread_destroy_worker(kworker_fie); > - return; > + cppc_freq_invariance_exit();
I don't really like this change, there aren't a lot of things that we need to do here on cleanup, but just kthread_destroy_worker(). Calling it directly makes more sense I guess.
> + fie_disabled = FIE_DISABLED; > } > } > > -static void cppc_freq_invariance_exit(void) > -{ > - if (fie_disabled) > - return; > - > - kthread_destroy_worker(kworker_fie);
> - kworker_fie = NULL;
I don't see the point of this line. Probably it can be dropped.
> -} > - > #else > static inline void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy) > { > -- > 2.34.1
-- viresh
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