make: *** [Makefile:121: config-host.mak] Error 1
[cborntra@m83lp52 qemu]$ make -C build/
make: Entering directory '/home/cborntra/REPOS/qemu/build'
Generating qemu-version.h with a meson_exe.py custom command
Compiling C object tools/virtiofsd/virtiofsd.p/passthrough_ll.c.o
../tools/virtiofsd/passthrough_ll.c: In function ‘lo_setattr’:
../tools/virtiofsd/passthrough_ll.c:702:19: error: ‘fd’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  702 |             res = futimens(fd, tv);
      |                   ^~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make: *** [Makefile.ninja:1438: tools/virtiofsd/virtiofsd.p/passthrough_ll.c.o] Error 1
make: Leaving directory '/home/cborntra/REPOS/

as far as I can see this can not happen. Let us silence the warning by
giving fd a default value.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 tools/virtiofsd/passthrough_ll.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 0b229ebd5786..da06aa6e9264 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -620,7 +620,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
     struct lo_inode *inode;
     int ifd;
     int res;
-    int fd;
+    int fd = 0;
 
     inode = lo_inode(req, ino);
     if (!inode) {
-- 
2.26.2

* Christian Borntraeger (borntraeger@de.ibm.com) wrote:
> make: *** [Makefile:121: config-host.mak] Error 1
> [cborntra@m83lp52 qemu]$ make -C build/
> make: Entering directory '/home/cborntra/REPOS/qemu/build'
> Generating qemu-version.h with a meson_exe.py custom command
> Compiling C object tools/virtiofsd/virtiofsd.p/passthrough_ll.c.o
> ../tools/virtiofsd/passthrough_ll.c: In function ‘lo_setattr’:
> ../tools/virtiofsd/passthrough_ll.c:702:19: error: ‘fd’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>   702 |             res = futimens(fd, tv);
>       |                   ^~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
> make: *** [Makefile.ninja:1438: tools/virtiofsd/virtiofsd.p/passthrough_ll.c.o] Error 1
> make: Leaving directory '/home/cborntra/REPOS/
> 
> as far as I can see this can not happen. Let us silence the warning by
> giving fd a default value.
> 
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

Yeh, I'd posted https://www.mail-archive.com/qemu-devel@nongnu.org/msg738783.html
but not yet merged it; only difference is I'd used -1 since it seemd
safer to use -1 even if it couldn't happen :-)

Dave

> ---
>  tools/virtiofsd/passthrough_ll.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
> index 0b229ebd5786..da06aa6e9264 100644
> --- a/tools/virtiofsd/passthrough_ll.c
> +++ b/tools/virtiofsd/passthrough_ll.c
> @@ -620,7 +620,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
>      struct lo_inode *inode;
>      int ifd;
>      int res;
> -    int fd;
> +    int fd = 0;
>  
>      inode = lo_inode(req, ino);
>      if (!inode) {
> -- 
> 2.26.2
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

On 30.09.20 18:27, Dr. David Alan Gilbert wrote:
> * Christian Borntraeger (borntraeger@de.ibm.com) wrote:
>> make: *** [Makefile:121: config-host.mak] Error 1
>> [cborntra@m83lp52 qemu]$ make -C build/
>> make: Entering directory '/home/cborntra/REPOS/qemu/build'
>> Generating qemu-version.h with a meson_exe.py custom command
>> Compiling C object tools/virtiofsd/virtiofsd.p/passthrough_ll.c.o
>> ../tools/virtiofsd/passthrough_ll.c: In function ‘lo_setattr’:
>> ../tools/virtiofsd/passthrough_ll.c:702:19: error: ‘fd’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>>   702 |             res = futimens(fd, tv);
>>       |                   ^~~~~~~~~~~~~~~~
>> cc1: all warnings being treated as errors
>> make: *** [Makefile.ninja:1438: tools/virtiofsd/virtiofsd.p/passthrough_ll.c.o] Error 1
>> make: Leaving directory '/home/cborntra/REPOS/
>>
>> as far as I can see this can not happen. Let us silence the warning by
>> giving fd a default value.
>>
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> 
> Yeh, I'd posted https://www.mail-archive.com/qemu-devel@nongnu.org/msg738783.html
> but not yet merged it; only difference is I'd used -1 since it seemd
> safer to use -1 even if it couldn't happen :-)

Agreed, lets go with your patch.