| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 072/140] cpufreq: powernv: fix stack bloat and hard limit on number of CPUs | Date | Mon, 16 Dec 2019 18:49:00 +0100 |
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From: John Hubbard <jhubbard@nvidia.com>
commit db0d32d84031188443e25edbd50a71a6e7ac5d1d upstream.
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 with a cross-compiler based on gcc 8.1.0, which I got from: https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/8.1.0/
The warning is due to putting 1024 bytes on the stack:
unsigned int chip[256];
...and it's also undesirable to have a hard limit on the number of CPUs here.
Fix both problems by dynamically allocating based on num_possible_cpus, as recommended by Michael Ellerman.
Fixes: 053819e0bf840 ("cpufreq: powernv: Handle throttling due to Pmax capping at chip level") Signed-off-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: 4.10+ <stable@vger.kernel.org> # 4.10+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/cpufreq/powernv-cpufreq.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
--- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -1042,9 +1042,14 @@ static struct cpufreq_driver powernv_cpu 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(num_possible_cpus(), sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; for_each_possible_cpu(cpu) { unsigned int id = cpu_to_chip_id(cpu); @@ -1056,8 +1061,10 @@ 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]; @@ -1067,7 +1074,9 @@ 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)
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