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From: Dan Carpenter <dan.carpenter@oracle.com>
To: robin.murphy@arm.com
Cc: linux-arm-kernel@lists.infradead.org
Subject: [bug report] perf: Add Arm CMN-600 PMU driver
Date: Wed, 30 Sep 2020 17:34:44 +0300	[thread overview]
Message-ID: <20200930143444.GA651504@mwanda> (raw)

Hello Robin Murphy,

The patch 0ba64770a2f2: "perf: Add Arm CMN-600 PMU driver" from Sep
18, 2020, leads to the following static checker warning:

	drivers/perf/arm-cmn.c:1156 arm_cmn_pmu_offline_cpu()
	error: potential NULL dereference 'cmn'.

drivers/perf/arm-cmn.c
  1150  static int arm_cmn_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
  1151  {
  1152          struct arm_cmn *cmn;
  1153          unsigned int target;
  1154  
  1155          cmn = hlist_entry_safe(node, struct arm_cmn, cpuhp_node);
  1156          if (cpu != cmn->cpu)
                           ^^^^^^^^
It doesn't make sense to use hlist_entry_safe() and then dereference
"cmn" without checking for NULL.  It should either be hlist_entry() or
there should be a NULL check.

  1157                  return 0;
  1158  
  1159          target = cpumask_any_but(cpu_online_mask, cpu);
  1160          if (target >= nr_cpu_ids)
  1161                  return 0;
  1162  
  1163          perf_pmu_migrate_context(&cmn->pmu, cpu, target);
  1164          cmn->cpu = target;
  1165          return 0;
  1166  }

regards,
dan carpenter

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             reply	other threads:[~2020-09-30 14:36 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-30 14:34 Dan Carpenter [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-09-30 14:36 [bug report] perf: Add Arm CMN-600 PMU driver Dan Carpenter

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