Re: [RFC] migration/dirtyrate: check malloc() return

[Alex Bennée]

Richard Henderson  writes:

> On 4/9/22 20:58, jianchunfu wrote:
>> Handling potential memory allocation failures in dirtyrate.
>> Signed-off-by: jianchunfu 
>> ---
>>   migration/dirtyrate.c | 8 
>>   1 file changed, 8 insertions(+)
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> index aace12a787..5dd40f32c8 100644
>> --- a/migration/dirtyrate.c
>> +++ b/migration/dirtyrate.c
>> @@ -523,9 +523,17 @@ static void calculate_dirtyrate_dirty_ring(struct 
>> DirtyRateConfig config)
>>   }
>> dirty_pages = malloc(sizeof(*dirty_pages) * nvcpu);
>> +if (!dirty_pages) {
>> +error_report("malloc dirty pages for vcpus failed.");
>> +exit(1);
>> +}
>> DirtyStat.dirty_ring.nvcpu = nvcpu;
>>   DirtyStat.dirty_ring.rates = malloc(sizeof(DirtyRateVcpu) * nvcpu);
>> +if (!DirtyStat.dirty_ring.rates) {
>> +error_report("malloc dirty rates for vcpu ring failed.");
>> +exit(1);
>> +}
>
> You might as well use g_new(), which handles the sizeof and
> multiplication, and error reporting.

It will also assert if the alloc fails. If this is an allocation QEMU
can recover from then you need to use the try_new variants of the
g_malloc/new functions. However here we are exiting so no actual check
is needed as the g_malloc will exit for us.

-- 
Alex Bennée

Re: [RFC] migration/dirtyrate: check malloc() return

[Richard Henderson]

On 4/9/22 20:58, jianchunfu wrote:

Handling potential memory allocation failures in dirtyrate.

Signed-off-by: jianchunfu 
---
  migration/dirtyrate.c | 8 
  1 file changed, 8 insertions(+)

diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index aace12a787..5dd40f32c8 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -523,9 +523,17 @@ static void calculate_dirtyrate_dirty_ring(struct 
DirtyRateConfig config)
  }
  
  dirty_pages = malloc(sizeof(*dirty_pages) * nvcpu);

+if (!dirty_pages) {
+error_report("malloc dirty pages for vcpus failed.");
+exit(1);
+}
  
  DirtyStat.dirty_ring.nvcpu = nvcpu;

  DirtyStat.dirty_ring.rates = malloc(sizeof(DirtyRateVcpu) * nvcpu);
+if (!DirtyStat.dirty_ring.rates) {
+error_report("malloc dirty rates for vcpu ring failed.");
+exit(1);
+}


You might as well use g_new(), which handles the sizeof and multiplication, and error 
reporting.



r~

[RFC] migration/dirtyrate: check malloc() return

[jianchunfu]

Handling potential memory allocation failures in dirtyrate.

Signed-off-by: jianchunfu 
---
 migration/dirtyrate.c | 8 
 1 file changed, 8 insertions(+)

diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index aace12a787..5dd40f32c8 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -523,9 +523,17 @@ static void calculate_dirtyrate_dirty_ring(struct 
DirtyRateConfig config)
 }
 
 dirty_pages = malloc(sizeof(*dirty_pages) * nvcpu);
+if (!dirty_pages) {
+error_report("malloc dirty pages for vcpus failed.");
+exit(1);
+}
 
 DirtyStat.dirty_ring.nvcpu = nvcpu;
 DirtyStat.dirty_ring.rates = malloc(sizeof(DirtyRateVcpu) * nvcpu);
+if (!DirtyStat.dirty_ring.rates) {
+error_report("malloc dirty rates for vcpu ring failed.");
+exit(1);
+}
 
 dirtyrate_global_dirty_log_start();
 
-- 
2.18.4