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[Qemu-devel] [PATCH v2] curl: Don't deref NULL pointer in call to aio_po
From: |
Richard W.M. Jones |
Subject: |
[Qemu-devel] [PATCH v2] curl: Don't deref NULL pointer in call to aio_poll. |
Date: |
Thu, 28 Aug 2014 09:04:21 +0100 |
In commit 63f0f45f2e89b60ff8245fec81328ddfde42a303 the following
mechanical change was made:
if (!state) {
- qemu_aio_wait();
+ aio_poll(state->s->aio_context, true);
}
The new code now checks if state is NULL and then dereferences it
('state->s') which is obviously incorrect.
This commit replaces state->s->aio_context with
bdrv_get_aio_context(bs), fixing this problem. The two other hunks
are concerned with getting the BlockDriverState pointer bs to where it
is needed.
The original bug causes a segfault when using libguestfs to access a
VMware vCenter Server and doing any kind of complex read-heavy
operations. With this commit the segfault goes away.
Signed-off-by: Richard W.M. Jones <address@hidden>
Reviewed-by: Paolo Bonzini <address@hidden>
---
block/curl.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/block/curl.c b/block/curl.c
index d4b85d2..f59615d 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -352,7 +352,7 @@ static void curl_multi_timeout_do(void *arg)
#endif
}
-static CURLState *curl_init_state(BDRVCURLState *s)
+static CURLState *curl_init_state(BlockDriverState *bs, BDRVCURLState *s)
{
CURLState *state = NULL;
int i, j;
@@ -370,7 +370,7 @@ static CURLState *curl_init_state(BDRVCURLState *s)
break;
}
if (!state) {
- aio_poll(state->s->aio_context, true);
+ aio_poll(bdrv_get_aio_context(bs), true);
}
} while(!state);
@@ -541,7 +541,7 @@ static int curl_open(BlockDriverState *bs, QDict *options,
int flags,
DPRINTF("CURL: Opening %s\n", file);
s->aio_context = bdrv_get_aio_context(bs);
s->url = g_strdup(file);
- state = curl_init_state(s);
+ state = curl_init_state(bs, s);
if (!state)
goto out_noclean;
@@ -625,7 +625,7 @@ static void curl_readv_bh_cb(void *p)
}
// No cache found, so let's start a new request
- state = curl_init_state(s);
+ state = curl_init_state(acb->common.bs, s);
if (!state) {
acb->common.cb(acb->common.opaque, -EIO);
qemu_aio_release(acb);
--
2.0.4