Re: [PATCH] powerpc/pseries: fix potential memory leak in init_cpu_associativity()

在 2022/12/13 14:06, Naveen N. Rao 写道:

Wang Yufen wrote:

quoted

If the vcpu_associativity alloc memory successfully but the
pcpu_associativity fails to alloc memory, the vcpu_associativity
memory leaks.

Fixes: d62c8deeb6e6 ("powerpc/pseries: Provide vcpu dispatch statistics")
Signed-off-by: Wang Yufen <redacted>
---
 arch/powerpc/platforms/pseries/lpar.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/platforms/pseries/lpar.c 

b/arch/powerpc/platforms/pseries/lpar.c
index 97ef649..501ee6c 100644

--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c

@@ -211,6 +211,7 @@ static int init_cpu_associativity(void)

     if (!vcpu_associativity || !pcpu_associativity) {
         pr_err("error allocating memory for associativity 
information\n");
+        kfree(vcpu_associativity);

I think we should call destroy_cpu_associativity() here instead. We 
don't know which allocation failed, so it is better to try and free 
both, and also to reset the pointers to 0.

Hi,

Okay, I'll send a v2 with the following modifications:

--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c

@@ -524,8 +524,10 @@ static ssize_t vcpudispatch_stats_write(struct file 

*file, const char __user *p,

  	if (cmd) {
  		rc = init_cpu_associativity();
-		if (rc)
+		if (rc) {
+			destroy_cpu_associativity();
  			goto out;
+		}

  		for_each_possible_cpu(cpu) {
  			disp = per_cpu_ptr(&vcpu_disp_data, cpu);

Thanks,
Wang

- Naveen