[PULL 13/55] block/qcow2-bitmap: Fix missing ERRP_GUARD() for error_prepend()

Thomas Huth posted 55 patches 1 year, 11 months ago
Maintainers: Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Yi Liu <yi.l.liu@intel.com>, Eric Auger <eric.auger@redhat.com>, Zhenzhong Duan <zhenzhong.duan@intel.com>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, John Snow <jsnow@redhat.com>, Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>, Eric Blake <eblake@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <fam@euphon.net>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Stefan Weil <sw@weilnetz.de>, Warner Losh <imp@bsdimp.com>, Kyle Evans <kevans@freebsd.org>, "Michael S. Tsirkin" <mst@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Yanan Wang <wangyanan55@huawei.com>, Jonathan Cameron <jonathan.cameron@huawei.com>, Fan Ni <fan.ni@samsung.com>, Laurent Vivier <laurent@vivier.eu>, Song Gao <gaosong@loongson.cn>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Alistair Francis <alistair@alistair23.me>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Peter Maydell <peter.maydell@linaro.org>, "Cédric Le Goater" <clg@kaod.org>, Nicholas Piggin <npiggin@gmail.com>, "Frédéric Barrat" <fbarrat@linux.ibm.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, David Gibson <david@gibson.dropbear.id.au>, Harsh Prateek Bora <harshpb@linux.ibm.com>, David Hildenbrand <david@redhat.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Thomas Huth <thuth@redhat.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Tony Krowiak <akrowiak@linux.ibm.com>, Jason Herne <jjherne@linux.ibm.com>, Alex Williamson <alex.williamson@redhat.com>, Stefano Stabellini <sstabellini@kernel.org>, Anthony Perard <anthony.perard@citrix.com>, Paul Durrant <paul@xen.org>, Markus Armbruster <armbru@redhat.com>, Michael Roth <michael.roth@amd.com>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, Jason Wang <jasowang@redhat.com>, Michael Rolnik <mrolnik@gmail.com>, Brian Cain <bcain@quicinc.com>, Cameron Esfahani <dirty@apple.com>, Roman Bolshakov <rbolshakov@ddn.com>, Reinoud Zandijk <reinoud@netbsd.org>, Sunil Muthuswamy <sunilmut@microsoft.com>, Aurelien Jarno <aurelien@aurel32.net>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, Huacai Chen <chenhuacai@kernel.org>, Chris Wulff <crwulff@gmail.com>, Marek Vasut <marex@denx.de>, Stafford Horne <shorne@gmail.com>, Palmer Dabbelt <palmer@dabbelt.com>, Bin Meng <bin.meng@windriver.com>, Weiwei Li <liwei1518@gmail.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Yoshinori Sato <ysato@users.sourceforge.jp>, Artyom Tarasenko <atar4qemu@gmail.com>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, Max Filippov <jcmvbkbc@gmail.com>
[PULL 13/55] block/qcow2-bitmap: Fix missing ERRP_GUARD() for error_prepend()
Posted by Thomas Huth 1 year, 11 months ago
From: Zhao Liu <zhao1.liu@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].

The qcow2_co_can_store_new_dirty_bitmap() passes @errp to
error_prepend(). As a BlockDriver.bdrv_co_can_store_new_dirty_bitmap
method, it's called by bdrv_co_can_store_new_dirty_bitmap().

Its caller is not being called anywhere, but as the API in
include/block/block-io.h, we can't ensure what kind of @errp future
users will pass in.

To avoid potential issues as [1] said, add missing ERRP_GUARD() at the
beginning of qcow2_co_can_store_new_dirty_bitmap().

[1]: Issue description in the commit message of commit ae7c80a7bd73
     ("error: New macro ERRP_GUARD()").

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Hanna Reitz <hreitz@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
Cc: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Cc: John Snow <jsnow@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-ID: <20240311033822.3142585-8-zhao1.liu@linux.intel.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 block/qcow2-bitmap.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index 0e567ed588..874ea56948 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -1710,6 +1710,7 @@ bool coroutine_fn qcow2_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
                                                       uint32_t granularity,
                                                       Error **errp)
 {
+    ERRP_GUARD();
     BDRVQcow2State *s = bs->opaque;
     BdrvDirtyBitmap *bitmap;
     uint64_t bitmap_directory_size = 0;
-- 
2.44.0