From a87f7f01dbdf6d87d6cd0f1a2e48341d4b2269ba Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Date: Fri, 13 Sep 2019 14:12:25 +0200 Subject: [PATCH 2/4] block/create: Do not abort if a block driver is not available MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Philippe Mathieu-Daudé Message-id: <20190913141225.12022-2-philmd@redhat.com> Patchwork-id: 90451 O-Subject: [RHEL-7.7 qemu-kvm-rhev + RHEL-AV-8.1.0 qemu-kvm PATCH v2 1/1] block/create: Do not abort if a block driver is not available Bugzilla: 1746224 RH-Acked-by: Kevin Wolf RH-Acked-by: John Snow RH-Acked-by: Stefan Hajnoczi The 'blockdev-create' QMP command was introduced as experimental feature in commit b0292b851b8, using the assert() debug call. It got promoted to 'stable' command in 3fb588a0f2c, but the assert call was not removed. Some block drivers are optional, and bdrv_find_format() might return a NULL value, triggering the assertion. Stable code is not expected to abort, so return an error instead. This is easily reproducible when libnfs is not installed: ./configure [...] module support no Block whitelist (rw) Block whitelist (ro) libiscsi support yes libnfs support no [...] Start QEMU: $ qemu-system-x86_64 -S -qmp unix:/tmp/qemu.qmp,server,nowait Send the 'blockdev-create' with the 'nfs' driver: $ ( cat << 'EOF' {'execute': 'qmp_capabilities'} {'execute': 'blockdev-create', 'arguments': {'job-id': 'x', 'options': {'size': 0, 'driver': 'nfs', 'location': {'path': '/', 'server': {'host': '::1', 'type': 'inet'}}}}, 'id': 'x'} EOF ) | socat STDIO UNIX:/tmp/qemu.qmp {"QMP": {"version": {"qemu": {"micro": 50, "minor": 1, "major": 4}, "package": "v4.1.0-733-g89ea03a7dc"}, "capabilities": ["oob"]}} {"return": {}} QEMU crashes: $ gdb qemu-system-x86_64 core Program received signal SIGSEGV, Segmentation fault. (gdb) bt #0 0x00007ffff510957f in raise () at /lib64/libc.so.6 #1 0x00007ffff50f3895 in abort () at /lib64/libc.so.6 #2 0x00007ffff50f3769 in _nl_load_domain.cold.0 () at /lib64/libc.so.6 #3 0x00007ffff5101a26 in .annobin_assert.c_end () at /lib64/libc.so.6 #4 0x0000555555d7e1f1 in qmp_blockdev_create (job_id=0x555556baee40 "x", options=0x555557666610, errp=0x7fffffffc770) at block/create.c:69 #5 0x0000555555c96b52 in qmp_marshal_blockdev_create (args=0x7fffdc003830, ret=0x7fffffffc7f8, errp=0x7fffffffc7f0) at qapi/qapi-commands-block-core.c:1314 #6 0x0000555555deb0a0 in do_qmp_dispatch (cmds=0x55555645de70 , request=0x7fffdc005c70, allow_oob=false, errp=0x7fffffffc898) at qapi/qmp-dispatch.c:131 #7 0x0000555555deb2a1 in qmp_dispatch (cmds=0x55555645de70 , request=0x7fffdc005c70, allow_oob=false) at qapi/qmp-dispatch.c:174 With this patch applied, QEMU returns a QMP error: {'execute': 'blockdev-create', 'arguments': {'job-id': 'x', 'options': {'size': 0, 'driver': 'nfs', 'location': {'path': '/', 'server': {'host': '::1', 'type': 'inet'}}}}, 'id': 'x'} {"id": "x", "error": {"class": "GenericError", "desc": "Block driver 'nfs' not found or not supported"}} Cc: qemu-stable@nongnu.org Reported-by: Xu Tian Signed-off-by: Philippe Mathieu-Daudé Reviewed-by: Eric Blake Reviewed-by: John Snow Signed-off-by: Kevin Wolf (cherry picked from commit d90d5cae2b10efc0e8d0b3cc91ff16201853d3ba) Signed-off-by: Philippe Mathieu-Daudé Signed-off-by: Miroslav Rezanina --- block/create.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/block/create.c b/block/create.c index 9534121..de5e97b 100644 --- a/block/create.c +++ b/block/create.c @@ -63,9 +63,13 @@ void qmp_blockdev_create(const char *job_id, BlockdevCreateOptions *options, const char *fmt = BlockdevDriver_str(options->driver); BlockDriver *drv = bdrv_find_format(fmt); + if (!drv) { + error_setg(errp, "Block driver '%s' not found or not supported", fmt); + return; + } + /* If the driver is in the schema, we know that it exists. But it may not * be whitelisted. */ - assert(drv); if (bdrv_uses_whitelist() && !bdrv_is_whitelisted(drv, false)) { error_setg(errp, "Driver is not whitelisted"); return; -- 1.8.3.1