diff mbox series

[PULL,5/5] aio: fix assert when remove poll during destroy

Message ID 20171003191227.11845-6-stefanha@redhat.com
State New
Headers show
Series [PULL,1/5] qom: provide root container for internal objs | expand

Commit Message

Stefan Hajnoczi Oct. 3, 2017, 7:12 p.m. UTC 
After iothread is enabled internally inside QEMU with GMainContext, we
may encounter this warning when destroying the iothread:

(qemu-system-x86_64:19925): GLib-CRITICAL **: g_source_remove_poll:
 assertion '!SOURCE_DESTROYED (source)' failed

The problem is that g_source_remove_poll() does not allow to remove one
source from array if the source is detached from its owner
context. (peterx: which IMHO does not make much sense)

Fix it on QEMU side by avoid calling g_source_remove_poll() if we know
the object is during destruction, and we won't leak anything after all
since the array will be gone soon cleanly even with that fd.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-id: 20170928025958.1420-6-peterx@redhat.com
[peterx: write the commit message]
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 util/aio-posix.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
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Patch

diff --git a/util/aio-posix.c b/util/aio-posix.c
index 2d51239ec6..5946ac09f0 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -223,7 +223,14 @@  void aio_set_fd_handler(AioContext *ctx,
             return;
         }
 
-        g_source_remove_poll(&ctx->source, &node->pfd);
+        /* If the GSource is in the process of being destroyed then
+         * g_source_remove_poll() causes an assertion failure.  Skip
+         * removal in that case, because glib cleans up its state during
+         * destruction anyway.
+         */
+        if (!g_source_is_destroyed(&ctx->source)) {
+            g_source_remove_poll(&ctx->source, &node->pfd);
+        }
 
         /* If the lock is held, just mark the node as deleted */
         if (qemu_lockcnt_count(&ctx->list_lock)) {