From: John Hubbard <jhubbard@nvidia.com>
To: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Cc: linux-pm@vger.kernel.org, John Hubbard <jhubbard@nvidia.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
LKML <linux-kernel@vger.kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Preeti U Murthy <preeti@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] cpufreq: powernv: fix stack bloat and NR_CPUS limitation
Date: Thu, 17 Oct 2019 17:04:31 -0700 [thread overview]
Message-ID: <20191018000431.1675281-1-jhubbard@nvidia.com> (raw)
The following build warning occurred on powerpc 64-bit builds:
drivers/cpufreq/powernv-cpufreq.c: In function 'init_chip_info':
drivers/cpufreq/powernv-cpufreq.c:1070:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
This is due to putting 1024 bytes on the stack:
unsigned int chip[256];
...and while looking at this, it also has a bug: it fails with a stack
overrun, if CONFIG_NR_CPUS > 256.
Fix both problems by dynamically allocating based on CONFIG_NR_CPUS.
Fixes: 053819e0bf840 ("cpufreq: powernv: Handle throttling due to Pmax capping at chip level")
Cc: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
Hi,
I have only compile-tested this, so I would appreciate if anyone
could do a basic runtime test on it. But (famous last words) it
seems simple enough that I'm confident it's correct. oh boy. :)
thanks,
John Hubbard
NVIDIA
drivers/cpufreq/powernv-cpufreq.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 6061850e59c9..78e04402125f 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -1041,9 +1041,14 @@ static struct cpufreq_driver powernv_cpufreq_driver = {
static int init_chip_info(void)
{
- unsigned int chip[256];
+ unsigned int *chip;
unsigned int cpu, i;
unsigned int prev_chip_id = UINT_MAX;
+ int ret = 0;
+
+ chip = kcalloc(CONFIG_NR_CPUS, sizeof(int), GFP_KERNEL);
+ if (!chips)
+ return -ENOMEM;
for_each_possible_cpu(cpu) {
unsigned int id = cpu_to_chip_id(cpu);
@@ -1055,8 +1060,10 @@ static int init_chip_info(void)
}
chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
- if (!chips)
- return -ENOMEM;
+ if (!chips) {
+ ret = -ENOMEM;
+ goto free_and_return;
+ }
for (i = 0; i < nr_chips; i++) {
chips[i].id = chip[i];
@@ -1066,7 +1073,9 @@ static int init_chip_info(void)
per_cpu(chip_info, cpu) = &chips[i];
}
- return 0;
+free_and_return:
+ kfree(chip);
+ return ret;
}
static inline void clean_chip_info(void)
--
2.23.0
next reply other threads:[~2019-10-18 0:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-18 0:04 John Hubbard [this message]
2019-10-18 4:27 ` [PATCH] cpufreq: powernv: fix stack bloat and NR_CPUS limitation Viresh Kumar
2019-10-18 4:34 ` John Hubbard
2019-10-18 4:38 ` Viresh Kumar
2019-10-18 4:41 ` John Hubbard
2019-10-18 4:50 ` Viresh Kumar
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