Avoid race condition manipulating heap when goroutine exits.
From-SVN: r170758
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parent
457186f6d5
commit
691a924baf
@ -92,18 +92,15 @@ remove_current_thread (void)
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if (list_entry->next != NULL)
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list_entry->next->prev = list_entry->prev;
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/* This will look runtime_mheap as needed. */
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runtime_MCache_ReleaseAll (mcache);
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/* As soon as we release this look, a GC could run. Since this
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thread is no longer on the list, the GC will not find our M
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structure, so it could get freed at any time. That means that
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any code from here to thread exit must not assume that the m is
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valid. */
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m = NULL;
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i = pthread_mutex_unlock (&__go_thread_ids_lock);
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__go_assert (i == 0);
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/* This should never deadlock--there shouldn't be any code that
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holds the runtime_mheap lock when locking __go_thread_ids_lock.
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We don't want to do this after releasing __go_thread_ids_lock
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because it will mean that the garbage collector might run, and
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the garbage collector does not try to lock runtime_mheap in all
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cases since it knows it is running single-threaded. */
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runtime_lock (&runtime_mheap);
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mstats.heap_alloc += mcache->local_alloc;
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mstats.heap_objects += mcache->local_objects;
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@ -111,6 +108,16 @@ remove_current_thread (void)
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runtime_FixAlloc_Free (&runtime_mheap.cachealloc, mcache);
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runtime_unlock (&runtime_mheap);
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/* As soon as we release this look, a GC could run. Since this
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thread is no longer on the list, the GC will not find our M
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structure, so it could get freed at any time. That means that
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any code from here to thread exit must not assume that m is
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valid. */
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m = NULL;
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i = pthread_mutex_unlock (&__go_thread_ids_lock);
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__go_assert (i == 0);
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free (list_entry);
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}
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