From 6bfda7ce56e7d14a677b7bcd6c7a5009cc29aa88 Mon Sep 17 00:00:00 2001 From: David Arcari Date: Tue, 24 Feb 2026 07:21:06 -0500 Subject: cpufreq: intel_pstate: Fix NULL pointer dereference in update_cpu_qos_request() commit ab39cc4cb8ceecdc2b61747433e7237f1ac2b789 upstream. The update_cpu_qos_request() function attempts to initialize the 'freq' variable by dereferencing 'cpudata' before verifying if the 'policy' is valid. This issue occurs on systems booted with the "nosmt" parameter, where all_cpu_data[cpu] is NULL for the SMT sibling threads. As a result, any call to update_qos_requests() will result in a NULL pointer dereference as the code will attempt to access pstate.turbo_freq using the NULL cpudata pointer. Also, pstate.turbo_freq may be updated by intel_pstate_get_hwp_cap() after initializing the 'freq' variable, so it is better to defer the 'freq' until intel_pstate_get_hwp_cap() has been called. Fix this by deferring the 'freq' assignment until after the policy and driver_data have been validated. Fixes: ae1bdd23b99f ("cpufreq: intel_pstate: Adjust frequency percentage computations") Reported-by: Jirka Hladky Closes: https://lore.kernel.org/all/CAE4VaGDfiPvz3AzrwrwM4kWB3SCkMci25nPO8W1JmTBd=xHzZg@mail.gmail.com/ Signed-off-by: David Arcari Cc: 6.18+ # 6.18+ [ rjw: Added one paragraph to the changelog ] Link: https://patch.msgid.link/20260224122106.228116-1-darcari@redhat.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/intel_pstate.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/cpufreq/intel_pstate.c') diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 00b87f8ee70b..5efda8af4b70 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1663,8 +1663,8 @@ unlock_driver: static void update_cpu_qos_request(int cpu, enum freq_qos_req_type type) { struct cpudata *cpudata = all_cpu_data[cpu]; - unsigned int freq = cpudata->pstate.turbo_freq; struct freq_qos_request *req; + unsigned int freq; struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(cpu); if (!policy) @@ -1677,6 +1677,8 @@ static void update_cpu_qos_request(int cpu, enum freq_qos_req_type type) if (hwp_active) intel_pstate_get_hwp_cap(cpudata); + freq = cpudata->pstate.turbo_freq; + if (type == FREQ_QOS_MIN) { freq = DIV_ROUND_UP(freq * global.min_perf_pct, 100); } else { -- cgit v1.2.3