aboutsummaryrefslogtreecommitdiff
path: root/async.c
diff options
context:
space:
mode:
authorKevin Wolf <kwolf@redhat.com>2011-09-01 16:16:10 +0200
committerKevin Wolf <kwolf@redhat.com>2011-09-06 11:23:51 +0200
commit648fb0ea5e9d7f32c80ec23c3ece4321403dfecd (patch)
tree5b0c1010a027aa79139a0dd2bd205a7984effa57 /async.c
parent0fa9131a44943cc14c931a23eee040da4cc0c454 (diff)
downloadqemu-arm-648fb0ea5e9d7f32c80ec23c3ece4321403dfecd.tar.gz
async: Allow nested qemu_bh_poll calls
qemu may segfault when a BH handler first deletes a BH and then (possibly indirectly) calls a nested qemu_bh_poll(). This is because the inner instance frees the BH and deletes it from the list that the outer one processes. This patch deletes BHs only in the outermost qemu_bh_poll instance. Commit 7887f620 already tried to achieve the same, but it assumed that the BH handler would only delete its own BH. With a nested qemu_bh_poll(), this isn't guaranteed, so that commit wasn't enough. Hope this one fixes it for real. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'async.c')
-rw-r--r--async.c24
1 files changed, 16 insertions, 8 deletions
diff --git a/async.c b/async.c
index 9d4e960b02..ca13962222 100644
--- a/async.c
+++ b/async.c
@@ -55,6 +55,9 @@ int qemu_bh_poll(void)
{
QEMUBH *bh, **bhp, *next;
int ret;
+ static int nesting = 0;
+
+ nesting++;
ret = 0;
for (bh = first_bh; bh; bh = next) {
@@ -68,15 +71,20 @@ int qemu_bh_poll(void)
}
}
+ nesting--;
+
/* remove deleted bhs */
- bhp = &first_bh;
- while (*bhp) {
- bh = *bhp;
- if (bh->deleted) {
- *bhp = bh->next;
- g_free(bh);
- } else
- bhp = &bh->next;
+ if (!nesting) {
+ bhp = &first_bh;
+ while (*bhp) {
+ bh = *bhp;
+ if (bh->deleted) {
+ *bhp = bh->next;
+ g_free(bh);
+ } else {
+ bhp = &bh->next;
+ }
+ }
}
return ret;