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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2025-09-05 15:52:03 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-10-19 16:23:12 +0200 |
| commit | 0a58d3e77b22b087a57831c87cafd360e144a5bd (patch) | |
| tree | 72e32be2d97948a00eff26ba2ddf0182fe9fa287 /drivers | |
| parent | 7204b0f8f665df9685409d8c8ab26cb4d7e49c3a (diff) | |
| download | linux-0a58d3e77b22b087a57831c87cafd360e144a5bd.tar.gz linux-0a58d3e77b22b087a57831c87cafd360e144a5bd.tar.bz2 linux-0a58d3e77b22b087a57831c87cafd360e144a5bd.zip | |
cpufreq: intel_pstate: Fix object lifecycle issue in update_qos_request()
commit 69e5d50fcf4093fb3f9f41c4f931f12c2ca8c467 upstream.
The cpufreq_cpu_put() call in update_qos_request() takes place too early
because the latter subsequently calls freq_qos_update_request() that
indirectly accesses the policy object in question through the QoS request
object passed to it.
Fortunately, update_qos_request() is called under intel_pstate_driver_lock,
so this issue does not matter for changing the intel_pstate operation
mode, but it theoretically can cause a crash to occur on CPU device hot
removal (which currently can only happen in virt, but it is formally
supported nevertheless).
Address this issue by modifying update_qos_request() to drop the
reference to the policy later.
Fixes: da5c504c7aae ("cpufreq: intel_pstate: Implement QoS supported freq constraints")
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Zihuan Zhang <zhangzihuan@kylinos.cn>
Link: https://patch.msgid.link/2255671.irdbgypaU6@rafael.j.wysocki
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/cpufreq/intel_pstate.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 3ded51db833d..5af471a7b752 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1308,10 +1308,10 @@ static void update_qos_request(enum freq_qos_req_type type) continue; req = policy->driver_data; - cpufreq_cpu_put(policy); - - if (!req) + if (!req) { + cpufreq_cpu_put(policy); continue; + } if (hwp_active) intel_pstate_get_hwp_cap(cpu); @@ -1327,6 +1327,8 @@ static void update_qos_request(enum freq_qos_req_type type) if (freq_qos_update_request(req, freq) < 0) pr_warn("Failed to update freq constraint: CPU%d\n", i); + + cpufreq_cpu_put(policy); } } |