From: Zhao Liu <zhao1....@intel.com>
As the comment in qapi/error, passing @errp to error_prepend() requires
ERRP_GUARD():
* = Why, when and how to use ERRP_GUARD() =
*
* Without ERRP_GUARD(), use of the @errp parameter is restricted:
...
* - It should not be passed to error_prepend(), error_vprepend() or
* error_append_hint(), because that doesn't work with &error_fatal.
* ERRP_GUARD() lifts these restrictions.
*
* To use ERRP_GUARD(), add it right at the beginning of the function.
* @errp can then be used without worrying about the argument being
* NULL or &error_fatal.
ERRP_GUARD() could avoid the case when @errp is &error_fatal, the user
can't see this additional information, because exit() happens in
error_setg earlier than information is added [1].
In block/qcow2.c, there are 2 functions passing @errp to error_prepend()
without ERRP_GUARD():
- qcow2_co_create()
- qcow2_co_truncate()
There are too many possible callers to check the impact of the defect;
it may or may not be harmless. Thus it is necessary to protect @errp with
ERRP_GUARD().
Therefore, to avoid the issue like [1] said, add missing ERRP_GUARD() at
their beginning.
[1]: Issue description in the commit message of commit ae7c80a7bd73
("error: New macro ERRP_GUARD()").
Cc: Kevin Wolf <kw...@redhat.com>
Cc: Hanna Reitz <hre...@redhat.com>
Cc: qemu-bl...@nongnu.org
Signed-off-by: Zhao Liu <zhao1....@intel.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
Message-ID: <20240311033822.3142585-9-zhao1....@linux.intel.com>
Signed-off-by: Thomas Huth <th...@redhat.com>
---
block/qcow2.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/block/qcow2.c b/block/qcow2.c
index 204f5854cf..956128b409 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3483,6 +3483,7 @@ static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts
*opts, int version,
static int coroutine_fn GRAPH_UNLOCKED
qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
{
+ ERRP_GUARD();
BlockdevCreateOptionsQcow2 *qcow2_opts;
QDict *options;
@@ -4283,6 +4284,7 @@ static int coroutine_fn GRAPH_RDLOCK
qcow2_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
PreallocMode prealloc, BdrvRequestFlags flags, Error **errp)
{
+ ERRP_GUARD();
BDRVQcow2State *s = bs->opaque;
uint64_t old_length;
int64_t new_l1_size;
--
2.44.0
