[Devel] [PATCH VZ10 12/12] ve: Guard ve from ve_list with ve_list_lock

[Pavel Tikhomirov]

On 12/2/25 00:28, Konstantin Khorenko wrote:
> On 11/24/25 12:20, Pavel Tikhomirov wrote:
>> Else we can get use after free on ve_struct.
>>
>> https://virtuozzo.atlassian.net/browse/VSTOR-118289
>> Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
>>
>> Feature: ve: ve generic structures
>> ---
>>   kernel/ve/vecalls.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/kernel/ve/vecalls.c b/kernel/ve/vecalls.c
>> index 6caf269fe5040..a9e82a1335403 100644
>> --- a/kernel/ve/vecalls.c
>> +++ b/kernel/ve/vecalls.c
>> @@ -120,6 +120,8 @@ static int vestat_seq_show(struct seq_file *m, void *v)
>>       struct kernel_cpustat kstat;
>>         entry = (struct list_head *)v;
>> +
>> +    guard(mutex)(&ve_list_lock);
>>       ve = list_entry(entry, struct ve_struct, ve_list);
>>         curve = get_exec_env();
>> @@ -275,6 +277,7 @@ static int veinfo_seq_show(struct seq_file *m, void *v)
>>   {
>>       struct ve_struct *ve;
>>   +    guard(mutex)(&ve_list_lock);
>>       ve = list_entry((struct list_head *)v, struct ve_struct, ve_list);
>>         /* second 0 is deprecated ve->class_id */
> 
>    static int devperms_seq_show(struct seq_file *m, void *v)
>    {
>        struct ve_struct *ve;
> 
> // need it here as well?
>        guard(mutex)(&ve_list_lock);
>        ve = list_entry(v, struct ve_struct, ve_list);
>        ...
>    }

Oh, sadly I was completely wrong in this patch.

We have all three (vestat_seq_show(), devperms_seq_show() and veinfo_seq_show()) uses of ve_list already under ve_list_lock via ve_seq_start() + ve_seq_stop().

Thanks for Aleksei Oladko for pointing that out in slack.

So, let's revert this patch, as it wrongly introduces self-deadlocks.

> 

-- 
Best regards, Pavel Tikhomirov
Senior Software Developer, Virtuozzo.