[PATCH] perf/x86/amd/uncore: Fix memory leak for events array

[Sandipan Das]

When a CPU comes online, the per-CPU NB and LLC uncore contexts are
freed but not the events array within the context structure. This
causes a memory leak as identified by the kmemleak detector.

  [...]
  unreferenced object 0xffff8c5944b8e320 (size 32):
    comm "swapper/0", pid 1, jiffies 4294670387 (age 151.072s)
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<000000000759fb79>] amd_uncore_cpu_up_prepare+0xaf/0x230
      [<00000000ddc9e126>] cpuhp_invoke_callback+0x2cf/0x470
      [<0000000093e727d4>] cpuhp_issue_call+0x14d/0x170
      [<0000000045464d54>] __cpuhp_setup_state_cpuslocked+0x11e/0x330
      [<0000000069f67cbd>] __cpuhp_setup_state+0x6b/0x110
      [<0000000015365e0f>] amd_uncore_init+0x260/0x321
      [<00000000089152d2>] do_one_initcall+0x3f/0x1f0
      [<000000002d0bd18d>] kernel_init_freeable+0x1ca/0x212
      [<0000000030be8dde>] kernel_init+0x11/0x120
      [<0000000059709e59>] ret_from_fork+0x22/0x30
  unreferenced object 0xffff8c5944b8dd40 (size 64):
    comm "swapper/0", pid 1, jiffies 4294670387 (age 151.072s)
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<00000000306efe8b>] amd_uncore_cpu_up_prepare+0x183/0x230
      [<00000000ddc9e126>] cpuhp_invoke_callback+0x2cf/0x470
      [<0000000093e727d4>] cpuhp_issue_call+0x14d/0x170
      [<0000000045464d54>] __cpuhp_setup_state_cpuslocked+0x11e/0x330
      [<0000000069f67cbd>] __cpuhp_setup_state+0x6b/0x110
      [<0000000015365e0f>] amd_uncore_init+0x260/0x321
      [<00000000089152d2>] do_one_initcall+0x3f/0x1f0
      [<000000002d0bd18d>] kernel_init_freeable+0x1ca/0x212
      [<0000000030be8dde>] kernel_init+0x11/0x120
      [<0000000059709e59>] ret_from_fork+0x22/0x30
  [...]

Fix the problem by freeing the events array before freeing the uncore
context.

Fixes: 39621c5808f5 ("perf/x86/amd/uncore: Use dynamic events array")
Reported-by: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Tested-by: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Signed-off-by: Sandipan Das <sandipan.das@xxxxxxx>
---
 arch/x86/events/amd/uncore.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index d568afc705d2..83f15fe411b3 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -553,6 +553,7 @@ static void uncore_clean_online(void)
 
 	hlist_for_each_entry_safe(uncore, n, &uncore_unused_list, node) {
 		hlist_del(&uncore->node);
+		kfree(uncore->events);
 		kfree(uncore);
 	}
 }
-- 
2.34.1