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cpufreq: amd-pstate: avoid uninitialized variable use
The new epp support causes warnings about three separate
but related bugs:
1) failing before allocation should just return an error:
drivers/cpufreq/amd-pstate.c:951:6: error: variable 'ret' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (!dev)
^~~~
drivers/cpufreq/amd-pstate.c:1018:9: note: uninitialized use occurs here
return ret;
^~~
2) wrong variable to store return code:
drivers/cpufreq/amd-pstate.c:963:6: error: variable 'ret' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (rc)
^~
drivers/cpufreq/amd-pstate.c:1019:9: note: uninitialized use occurs here
return ret;
^~~
drivers/cpufreq/amd-pstate.c:963:2: note: remove the 'if' if its condition is always false
if (rc)
^~~~~~~
3) calling amd_pstate_set_epp() in cleanup path after determining
that it should not be called:
drivers/cpufreq/amd-pstate.c:1055:6: error: variable 'epp' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (cpudata->epp_policy == cpudata->policy)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/cpufreq/amd-pstate.c:1080:30: note: uninitialized use occurs here
amd_pstate_set_epp(cpudata, epp);
^~~
All three are trivial to fix, but most likely there are additional bugs
in this function when the error handling was not really tested.
Fixes: ffa5096a7c
("cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Reviewed-by: Yuan Perry <Perry.Yuan@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
parent
dd329e1e21
commit
7cca9a9851
1 changed files with 4 additions and 5 deletions
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@ -940,7 +940,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
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int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
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int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
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struct amd_cpudata *cpudata;
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struct amd_cpudata *cpudata;
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struct device *dev;
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struct device *dev;
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int rc;
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u64 value;
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u64 value;
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/*
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/*
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@ -950,7 +949,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
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amd_perf_ctl_reset(policy->cpu);
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amd_perf_ctl_reset(policy->cpu);
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dev = get_cpu_device(policy->cpu);
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dev = get_cpu_device(policy->cpu);
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if (!dev)
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if (!dev)
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goto free_cpudata1;
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return -ENODEV;
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cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL);
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cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL);
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if (!cpudata)
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if (!cpudata)
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@ -959,8 +958,8 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
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cpudata->cpu = policy->cpu;
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cpudata->cpu = policy->cpu;
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cpudata->epp_policy = 0;
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cpudata->epp_policy = 0;
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rc = amd_pstate_init_perf(cpudata);
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ret = amd_pstate_init_perf(cpudata);
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if (rc)
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if (ret)
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goto free_cpudata1;
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goto free_cpudata1;
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min_freq = amd_get_min_freq(cpudata);
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min_freq = amd_get_min_freq(cpudata);
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@ -1076,9 +1075,9 @@ static void amd_pstate_epp_init(unsigned int cpu)
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value |= (u64)epp << 24;
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value |= (u64)epp << 24;
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}
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}
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amd_pstate_set_epp(cpudata, epp);
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skip_epp:
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skip_epp:
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WRITE_ONCE(cpudata->cppc_req_cached, value);
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WRITE_ONCE(cpudata->cppc_req_cached, value);
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amd_pstate_set_epp(cpudata, epp);
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cpufreq_cpu_put(policy);
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cpufreq_cpu_put(policy);
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}
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}
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