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powercap: dtpm_cpu: Fix NULL pointer dereference in get_pd_power_uw()

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The get_pd_power_uw() function can crash with a NULL pointer dereference
when em_cpu_get() returns NULL. This occurs when a CPU becomes impossible
during runtime, causing get_cpu_device() to return NULL, which propagates
through em_cpu_get() and leads to a crash when em_span_cpus() dereferences
the NULL pointer.

Add a NULL check after em_cpu_get() and return 0 if unavailable,
matching the existing fallback behavior in __dtpm_cpu_setup().

Fixes: eb82bace89 ("powercap/drivers/dtpm: Scale the power with the load")
Signed-off-by: Sivan Zohar-Kotzer <sivany32@gmail.com>
Link: https://patch.msgid.link/20250701221355.96916-1-sivany32@gmail.com
[ rjw: Drop an excess empty code line ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Sivan Zohar-Kotzer 2025-07-02 01:13:55 +03:00 • committed by Rafael J. Wysocki
parent 82a7021f50
commit 46dc574068
1 changed files with 2 additions and 0 deletions
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2
drivers/powercap/dtpm_cpu.c
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@ -96,6 +96,8 @@ static u64 get_pd_power_uw(struct dtpm *dtpm)
int i; int i;
pd = em_cpu_get(dtpm_cpu->cpu); pd = em_cpu_get(dtpm_cpu->cpu);
if (!pd)
return 0;
pd_mask = em_span_cpus(pd); pd_mask = em_span_cpus(pd);