| User: | Jiri Slaby |
| Error type: | Double Lock |
| Error type description: | Some lock is locked twice unintentionally in a sequence |
| File location: | net/core/dev.c |
| Line in file: | 2403 |
| Project: | Linux Kernel |
| Project version: | 2.6.28 |
| Tools: |
Undetermined 1
|
| Entered: | 2012-02-27 21:22:42 UTC |
2373 struct list_head *list = &__get_cpu_var(softnet_data).poll_list; 2374 unsigned long start_time = jiffies; 2375 int budget = netdev_budget; 2376 void *have; 2377 2378 local_irq_disable(); 2379 2380 while (!list_empty(list)) { 2381 struct napi_struct *n; 2382 int work, weight; 2383 2384 /* If softirq window is exhuasted then punt. 2385 * 2386 * Note that this is a slight policy change from the 2387 * previous NAPI code, which would allow up to 2 2388 * jiffies to pass before breaking out. The test 2389 * used to be "jiffies - start_time > 1". 2390 */ 2391 if (unlikely(budget <= 0 || jiffies != start_time)) 2392 goto softnet_break; 2393 2394 local_irq_enable(); 2395 2396 /* Even though interrupts have been re-enabled, this 2397 * access is safe because interrupts can only add new 2398 * entries to the tail of this list, and only ->poll() 2399 * calls can remove this head entry from the list. 2400 */ 2401 n = list_entry(list->next, struct napi_struct, poll_list); 2402 2403 have = netpoll_poll_lock(n); 2404 2405 weight = n->weight; 2406 2407 /* This NAPI_STATE_SCHED test is for avoiding a race 2408 * with netpoll's poll_napi(). Only the entity which 2409 * obtains the lock and sees NAPI_STATE_SCHED set will 2410 * actually make the ->poll() call. Therefore we avoid 2411 * accidently calling ->poll() when NAPI is not scheduled. 2412 */ 2413 work = 0;