| Message ID | 1414510008-7262-2-git-send-email-tomeu.vizoso@collabora.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Tue, Oct 28, 2014 at 04:26:48PM +0100, Tomeu Vizoso wrote: > There's a substantial window of opportunity from the time the policy objects > are created until they are initialized, causing this: > > [ 4.651435] ------------[ cut here ]------------ > [ 4.651453] WARNING: CPU: 1 PID: 64 at include/linux/kref.h:47 kobject_get+0x64/0x70() > [ 4.651463] Modules linked in: > [ 4.651473] CPU: 1 PID: 64 Comm: irq/77-tegra-ac Not tainted 3.18.0-rc1-next-20141027ccu-00049-g21a0041 #248 > [ 4.651497] [<c0016fac>] (unwind_backtrace) from [<c001272c>] (show_stack+0x10/0x14) > [ 4.651505] [<c001272c>] (show_stack) from [<c0601920>] (dump_stack+0x98/0xd8) > [ 4.651515] [<c0601920>] (dump_stack) from [<c00288d8>] (warn_slowpath_common+0x70/0x8c) > [ 4.651522] [<c00288d8>] (warn_slowpath_common) from [<c0028990>] (warn_slowpath_null+0x1c/0x24) > [ 4.651530] [<c0028990>] (warn_slowpath_null) from [<c02227bc>] (kobject_get+0x64/0x70) > [ 4.651539] [<c02227bc>] (kobject_get) from [<c03e5238>] (cpufreq_cpu_get+0x88/0xc8) > [ 4.651547] [<c03e5238>] (cpufreq_cpu_get) from [<c03e52ec>] (cpufreq_get+0xc/0x64) > [ 4.651555] [<c03e52ec>] (cpufreq_get) from [<c0287818>] (actmon_thread_isr+0x140/0x1a4) > [ 4.651563] [<c0287818>] (actmon_thread_isr) from [<c0068a68>] (irq_thread_fn+0x1c/0x40) > [ 4.651570] [<c0068a68>] (irq_thread_fn) from [<c0068d84>] (irq_thread+0x134/0x174) > [ 4.651579] [<c0068d84>] (irq_thread) from [<c0040284>] (kthread+0xdc/0xf4) > [ 4.651587] [<c0040284>] (kthread) from [<c000f4b8>] (ret_from_fork+0x14/0x3c) > [ 4.651591] ---[ end trace 7f6a15d1272e6ef3 ]--- > > This commit checks that the policy object has been initialized already before > trying to ref it. > > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> > --- > drivers/cpufreq/cpufreq.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 644b54e..37cd6c9 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -214,8 +214,12 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) > if (cpufreq_driver) { > /* get the CPU */ > policy = per_cpu(cpufreq_cpu_data, cpu); > - if (policy) > - kobject_get(&policy->kobj); > + if (policy) { > + if (!kobject_initialized(&policy->kobj)) > + policy = NULL; > + else > + kobject_get(&policy->kobj); > + } Something else is going on here, sorry, this isn't the correct fix, as you are using kobjects incorrectly if this ever happens... thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 644b54e..37cd6c9 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -214,8 +214,12 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) if (cpufreq_driver) { /* get the CPU */ policy = per_cpu(cpufreq_cpu_data, cpu); - if (policy) - kobject_get(&policy->kobj); + if (policy) { + if (!kobject_initialized(&policy->kobj)) + policy = NULL; + else + kobject_get(&policy->kobj); + } } read_unlock_irqrestore(&cpufreq_driver_lock, flags);
There's a substantial window of opportunity from the time the policy objects are created until they are initialized, causing this: [ 4.651435] ------------[ cut here ]------------ [ 4.651453] WARNING: CPU: 1 PID: 64 at include/linux/kref.h:47 kobject_get+0x64/0x70() [ 4.651463] Modules linked in: [ 4.651473] CPU: 1 PID: 64 Comm: irq/77-tegra-ac Not tainted 3.18.0-rc1-next-20141027ccu-00049-g21a0041 #248 [ 4.651497] [<c0016fac>] (unwind_backtrace) from [<c001272c>] (show_stack+0x10/0x14) [ 4.651505] [<c001272c>] (show_stack) from [<c0601920>] (dump_stack+0x98/0xd8) [ 4.651515] [<c0601920>] (dump_stack) from [<c00288d8>] (warn_slowpath_common+0x70/0x8c) [ 4.651522] [<c00288d8>] (warn_slowpath_common) from [<c0028990>] (warn_slowpath_null+0x1c/0x24) [ 4.651530] [<c0028990>] (warn_slowpath_null) from [<c02227bc>] (kobject_get+0x64/0x70) [ 4.651539] [<c02227bc>] (kobject_get) from [<c03e5238>] (cpufreq_cpu_get+0x88/0xc8) [ 4.651547] [<c03e5238>] (cpufreq_cpu_get) from [<c03e52ec>] (cpufreq_get+0xc/0x64) [ 4.651555] [<c03e52ec>] (cpufreq_get) from [<c0287818>] (actmon_thread_isr+0x140/0x1a4) [ 4.651563] [<c0287818>] (actmon_thread_isr) from [<c0068a68>] (irq_thread_fn+0x1c/0x40) [ 4.651570] [<c0068a68>] (irq_thread_fn) from [<c0068d84>] (irq_thread+0x134/0x174) [ 4.651579] [<c0068d84>] (irq_thread) from [<c0040284>] (kthread+0xdc/0xf4) [ 4.651587] [<c0040284>] (kthread) from [<c000f4b8>] (ret_from_fork+0x14/0x3c) [ 4.651591] ---[ end trace 7f6a15d1272e6ef3 ]--- This commit checks that the policy object has been initialized already before trying to ref it. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> --- drivers/cpufreq/cpufreq.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)