Hello Nicolas Saenz Julienne,
The patch 46e4b9ec4fa4: "staging: vchiq_arm: use list_for_each_entry
when accessing bulk_waiter_list" from Nov 20, 2018, leads to the
following static checker warning:
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:427 vchiq_blocking_bulk_transfer()
warn: iterator used outside loop: 'waiter'
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
417 mutex_lock(&instance->bulk_waiter_list_mutex);
418 list_for_each_entry(waiter, &instance->bulk_waiter_list, list) {
^^^^^^^^^^^^^^^^^^^^^^^^^^
The list iterator is always non-NULL.
419 if (waiter->pid == current->pid) {
420 list_del(&waiter->list);
421 break;
422 }
423 }
424 mutex_unlock(&instance->bulk_waiter_list_mutex);
425
426 if (waiter) {
^^^^^^
In the original code "waiter" was only non-NULL if we found the correct
pid, but now it's always non-NULL.
427 struct vchiq_bulk *bulk = waiter->bulk_waiter.bulk;
428
429 if (bulk) {
430 /* This thread has an outstanding bulk transfer. */
431 if ((bulk->data != data) ||
432 (bulk->size != size)) {
433 /* This is not a retry of the previous one.
434 * Cancel the signal when the transfer
435 * completes.
436 */
437 spin_lock(&bulk_waiter_spinlock);
438 bulk->userdata = NULL;
439 spin_unlock(&bulk_waiter_spinlock);
440 }
441 }
442 }
443
444 if (!waiter) {
^^^^^^^
This is dead code now. I'm a bit surprised this bug didn't show up
during testing.
445 waiter = kzalloc(sizeof(struct bulk_waiter_node), GFP_KERNEL);
446 if (!waiter) {
447 vchiq_log_error(vchiq_core_log_level,
448 "%s - out of memory", __func__);
449 return VCHIQ_ERROR;
450 }
451 }
452
453 status = vchiq_bulk_transfer(handle, data, size, &waiter->bulk_waiter,
regards,
dan carpenter
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