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authorArnd Bergmann <arnd@arndb.de>2023-02-07 19:12:51 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2023-02-09 22:21:42 +0300
commit7cca9a9851a5fb44808949539af6c0428e48a267 (patch)
treed9aaa65824fe59178c5044d49e044a7effd37ba4 /drivers/cpufreq
parentdd329e1e21b54c73f58a440b6164d04d8a7fc542 (diff)
downloadlinux-7cca9a9851a5fb44808949539af6c0428e48a267.tar.xz
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.c9
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);
}