http://bugs.dpdk.org/show_bug.cgi?id=1876
Bug ID: 1876
Summary: enic: pthread mutex in shared memory missing
PTHREAD_PROCESS_SHARED (
Product: DPDK
Version: 25.11
Hardware: All
OS: All
Status: UNCONFIRMED
Severity: normal
Priority: Normal
Component: ethdev
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
This the enic driver portion of existing bug 662
The enic driver has a pthread mutex in shared memory that is initialized
without `PTHREAD_PROCESS_SHARED`, which causes undefined behavior when used
across multiple processes.
### Affected Mutex
1. **`enic->admin_chan_lock`** (`drivers/net/enic/enic_sriov.c`, line 352)
- Location: `struct enic` (device private data)
- Purpose: Protects SR-IOV admin channel operations between VF and PF
### Why This Is a Problem
The `struct enic` is the device private data accessed via
`eth_dev->data->dev_private`, which resides in shared memory accessible by both
primary and secondary processes.
The mutex is initialized in `enic_enable_vf_admin_chan()`:
```c
pthread_mutex_init(&enic->admin_chan_lock, NULL);
```
And used to protect admin channel operations:
```c
static void lock_admin_chan(struct enic *enic)
{
pthread_mutex_lock(&enic->admin_chan_lock);
}
static void unlock_admin_chan(struct enic *enic)
{
pthread_mutex_unlock(&enic->admin_chan_lock);
}
```
Per POSIX, mutexes in shared memory accessed by multiple processes must be
initialized with `PTHREAD_PROCESS_SHARED` attribute. Without this,
synchronization between processes is undefined behavior.
### Suggested Fix
Initialize the mutex with `PTHREAD_PROCESS_SHARED`:
```c
static void
enic_init_shared_mutex(pthread_mutex_t *mutex)
{
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
pthread_mutex_init(mutex, &attr);
pthread_mutexattr_destroy(&attr);
}
```
Then replace:
```c
pthread_mutex_init(&enic->admin_chan_lock, NULL);
```
With:
```c
enic_init_shared_mutex(&enic->admin_chan_lock);
```
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