Avoid potential deadlocks in channel_walk_locked, and detect serious failures
git-svn-id: http://svn.digium.com/svn/asterisk/trunk@3340 f38db490-d61c-443f-a65b-d21fe96a405b
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e4eae0813e
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19
channel.c
19
channel.c
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@ -452,6 +452,8 @@ struct ast_channel *ast_channel_walk_locked(struct ast_channel *prev)
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{
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/* Returns next channel (locked) */
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struct ast_channel *l, *ret=NULL;
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int retries = 0;
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retry:
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ast_mutex_lock(&chlock);
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l = channels;
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if (!prev) {
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@ -465,8 +467,21 @@ struct ast_channel *ast_channel_walk_locked(struct ast_channel *prev)
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ret = l->next;
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l = l->next;
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}
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if (ret)
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ast_mutex_lock(&ret->lock);
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if (ret) {
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if (ast_mutex_trylock(&ret->lock)) {
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if (retries < 10)
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ast_log(LOG_DEBUG, "Avoiding deadlock for '%s'\n", ret->name);
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else
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ast_log(LOG_WARNING, "Avoided deadlock for '%s', %d retries!\n", ret->name, retries);
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ast_mutex_unlock(&chlock);
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if (retries < 10) {
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usleep(1);
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retries++;
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goto retry;
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} else
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return NULL;
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}
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}
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ast_mutex_unlock(&chlock);
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return ret;
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