[xen master] cpufreq: don't leave stale statistics pointer

[patchbot@xxxxxxx]

commit a1ce987411f61dbf5fe64bba0cd3d36d7cc0311f
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Apr 30 08:47:49 2025 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Apr 30 08:47:49 2025 +0200

    cpufreq: don't leave stale statistics pointer
    
    Error paths of cpufreq_statistic_init() correctly free the base
    structure pointer, but the per-CPU variable would still hold it, mis-
    guiding e.g. cpufreq_statistic_update(). Defer installing of the pointer
    there until the structure was fully populated.
    
    Fixes: 755af07edba1 ("x86/cpufreq: don't use static array for large per-CPU 
data structures")
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/drivers/cpufreq/utility.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/drivers/cpufreq/utility.c b/xen/drivers/cpufreq/utility.c
index ac2889d496..309c0682cf 100644
--- a/xen/drivers/cpufreq/utility.c
+++ b/xen/drivers/cpufreq/utility.c
@@ -113,7 +113,6 @@ int cpufreq_statistic_init(unsigned int cpu)
         spin_unlock(cpufreq_statistic_lock);
         return -ENOMEM;
     }
-    per_cpu(cpufreq_statistic_data, cpu) = pxpt;
 
     pxpt->u.trans_pt = xzalloc_array(uint64_t, count * count);
     if (!pxpt->u.trans_pt) {
@@ -139,6 +138,8 @@ int cpufreq_statistic_init(unsigned int cpu)
     pxpt->prev_state_wall = NOW();
     pxpt->prev_idle_wall = get_cpu_idle_time(cpu);
 
+    per_cpu(cpufreq_statistic_data, cpu) = pxpt;
+
     spin_unlock(cpufreq_statistic_lock);
 
     return 0;
--
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