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author | 2023-02-07 17:12:51 +0100 | |
---|---|---|
committer | 2023-02-09 20:21:42 +0100 | |
commit | 7cca9a9851a5fb44808949539af6c0428e48a267 (patch) | |
tree | d9aaa65824fe59178c5044d49e044a7effd37ba4 /drivers/cpufreq | |
parent | cpufreq: Make cpufreq_unregister_driver() return void (diff) | |
download | linux-7cca9a9851a5fb44808949539af6c0428e48a267.tar.gz linux-7cca9a9851a5fb44808949539af6c0428e48a267.tar.bz2 linux-7cca9a9851a5fb44808949539af6c0428e48a267.zip |
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: ffa5096a7c33 ("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>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r-- | drivers/cpufreq/amd-pstate.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 70debd5a9f40..b8862afef4e4 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -940,7 +940,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret; struct amd_cpudata *cpudata; struct device *dev; - int rc; u64 value; /* @@ -950,7 +949,7 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) amd_perf_ctl_reset(policy->cpu); dev = get_cpu_device(policy->cpu); if (!dev) - goto free_cpudata1; + return -ENODEV; cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL); if (!cpudata) @@ -959,8 +958,8 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) cpudata->cpu = policy->cpu; cpudata->epp_policy = 0; - rc = amd_pstate_init_perf(cpudata); - if (rc) + ret = amd_pstate_init_perf(cpudata); + if (ret) goto free_cpudata1; min_freq = amd_get_min_freq(cpudata); @@ -1076,9 +1075,9 @@ static void amd_pstate_epp_init(unsigned int cpu) value |= (u64)epp << 24; } + amd_pstate_set_epp(cpudata, epp); skip_epp: WRITE_ONCE(cpudata->cppc_req_cached, value); - amd_pstate_set_epp(cpudata, epp); cpufreq_cpu_put(policy); } |