perf: Fix possible memleak in pmu_dev_alloc()

[ Upstream commit e8d7a90c08ce963c592fb49845f2ccc606a2ac21 ]

In pmu_dev_alloc(), when dev_set_name() failed, it will goto free_dev
and call put_device(pmu->dev) to release it.
However pmu->dev->release is assigned after this, which makes warning
and memleak.
Call dev_set_name() after pmu->dev->release = pmu_dev_release to fix it.

  Device '(null)' does not have a release() function...
  WARNING: CPU: 2 PID: 441 at drivers/base/core.c:2332 device_release+0x1b9/0x240
  ...
  Call Trace:
    <TASK>
    kobject_put+0x17f/0x460
    put_device+0x20/0x30
    pmu_dev_alloc+0x152/0x400
    perf_pmu_register+0x96b/0xee0
    ...
  kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
  unreferenced object 0xffff888014759000 (size 2048):
    comm "modprobe", pid 441, jiffies 4294931444 (age 38.332s)
    backtrace:
      [<0000000005aed3b4>] kmalloc_trace+0x27/0x110
      [<000000006b38f9b8>] pmu_dev_alloc+0x50/0x400
      [<00000000735f17be>] perf_pmu_register+0x96b/0xee0
      [<00000000e38477f1>] 0xffffffffc0ad8603
      [<000000004e162216>] do_one_initcall+0xd0/0x4e0
      ...

Fixes: abe43400579d ("perf: Sysfs enumeration")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221111103653.91058-1-chenzhongjin@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 7f04f99..732b392 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11193,13 +11193,15 @@ static int pmu_dev_alloc(struct pmu *pmu)
 
        pmu->dev->groups = pmu->attr_groups;
        device_initialize(pmu->dev);
-       ret = dev_set_name(pmu->dev, "%s", pmu->name);
-       if (ret)
-               goto free_dev;
 
        dev_set_drvdata(pmu->dev, pmu);
        pmu->dev->bus = &pmu_bus;
        pmu->dev->release = pmu_dev_release;
+
+       ret = dev_set_name(pmu->dev, "%s", pmu->name);
+       if (ret)
+               goto free_dev;
+
        ret = device_add(pmu->dev);
        if (ret)
                goto free_dev;