Messages in this thread | | | Date | Wed, 16 Aug 2023 13:47:08 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH] cpufreq: cppc: Add missing error pointer check |
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On 16-08-23, 15:27, Liao, Chang wrote: > Hi Viresh, > > 在 2023/8/16 11:46, Viresh Kumar 写道: > > On 16-08-23, 03:05, Liao Chang wrote: > >> The function cppc_freq_invariance_init() may failed to create > >> kworker_fie, make it more robust by checking the return value to prevent > >> an invalid pointer dereference in kthread_destroy_worker(), which called > >> from cppc_freq_invariance_exit(). > >> > >> Signed-off-by: Liao Chang <liaochang1@huawei.com> > >> --- > >> drivers/cpufreq/cppc_cpufreq.c | 21 ++++++++++++++------- > >> 1 file changed, 14 insertions(+), 7 deletions(-) > > > > I think why it was designed this way was to make the driver work, > > without invariance support, in the worst case instead of just failing > > completely. The invariance thing is a good to have feature, but not > > really necessary and so failing probing the driver for that isn't > > worth it. We should print all error messages though. > > > Thanks for pointing that out. I think you are right that the kworker created > in the cppc driver is not the only arch_freq_scale updater, the ARCH provided > updater has more priority than the driver, so the driver should still work even > without kworker_fie supports. > > If that is the case, i think the best thing to do is checking the error pointer > and printing an error message before calling kthread_destroy() in cppc_freq_invariance_exit(), > this is because at that point, it is really necessary to ensure the kworker_fie has > been initialized as expected, otherwise it will raise a NULL pointer exception.
Or just set fie_disabled to true ?
> I hope this makes sense, thanks.
It does.
-- viresh
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