* Re: [PATCH] virtiofs: Drop unnecessary initialization in send_forget_request and virtio_fs_get_tree
2022-09-06 5:38 [PATCH] virtiofs: Drop unnecessary initialization in send_forget_request and virtio_fs_get_tree Deming Wang
@ 2022-09-06 10:10 ` kernel test robot
2022-09-06 13:30 ` Stefan Hajnoczi
1 sibling, 0 replies; 3+ messages in thread
From: kernel test robot @ 2022-09-06 10:10 UTC (permalink / raw)
To: Deming Wang, vgoyal, stefanha, miklos
Cc: llvm, kbuild-all, virtualization, linux-fsdevel, linux-kernel,
Deming Wang
Hi Deming,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on v6.0-rc4]
[also build test WARNING on linus/master next-20220901]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Deming-Wang/virtiofs-Drop-unnecessary-initialization-in-send_forget_request-and-virtio_fs_get_tree/20220906-135058
base: 7e18e42e4b280c85b76967a9106a13ca61c16179
config: hexagon-randconfig-r035-20220906 (https://download.01.org/0day-ci/archive/20220906/202209061738.Epufa2eF-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project c55b41d5199d2394dd6cdb8f52180d8b81d809d4)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/a61f879fdb56490afddb6ddea4a9d57226f339f3
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Deming-Wang/virtiofs-Drop-unnecessary-initialization-in-send_forget_request-and-virtio_fs_get_tree/20220906-135058
git checkout a61f879fdb56490afddb6ddea4a9d57226f339f3
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/fuse/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> fs/fuse/virtio_fs.c:422:2: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (!fsvq->connected) {
^~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/fuse/virtio_fs.c:465:9: note: uninitialized use occurs here
return ret;
^~~
fs/fuse/virtio_fs.c:422:2: note: remove the 'if' if its condition is always false
if (!fsvq->connected) {
^~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:56:23: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
fs/fuse/virtio_fs.c:417:9: note: initialize the variable 'ret' to silence this warning
int ret;
^
= 0
>> fs/fuse/virtio_fs.c:1433:2: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (WARN_ON(virtqueue_size <= FUSE_HEADER_OVERHEAD))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/fuse/virtio_fs.c:1481:9: note: uninitialized use occurs here
return err;
^~~
fs/fuse/virtio_fs.c:1433:2: note: remove the 'if' if its condition is always false
if (WARN_ON(virtqueue_size <= FUSE_HEADER_OVERHEAD))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:56:23: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
fs/fuse/virtio_fs.c:1420:9: note: initialize the variable 'err' to silence this warning
int err;
^
= 0
2 warnings generated.
vim +422 fs/fuse/virtio_fs.c
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 406
58ada94f95f71d Vivek Goyal 2019-10-30 407 /*
58ada94f95f71d Vivek Goyal 2019-10-30 408 * Returns 1 if queue is full and sender should wait a bit before sending
58ada94f95f71d Vivek Goyal 2019-10-30 409 * next request, 0 otherwise.
58ada94f95f71d Vivek Goyal 2019-10-30 410 */
58ada94f95f71d Vivek Goyal 2019-10-30 411 static int send_forget_request(struct virtio_fs_vq *fsvq,
58ada94f95f71d Vivek Goyal 2019-10-30 412 struct virtio_fs_forget *forget,
58ada94f95f71d Vivek Goyal 2019-10-30 413 bool in_flight)
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 414 {
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 415 struct scatterlist sg;
58ada94f95f71d Vivek Goyal 2019-10-30 416 struct virtqueue *vq;
a61f879fdb5649 Deming Wang 2022-09-06 417 int ret;
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 418 bool notify;
1efcf39eb62757 Vivek Goyal 2019-10-30 419 struct virtio_fs_forget_req *req = &forget->req;
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 420
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 421 spin_lock(&fsvq->lock);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 @422 if (!fsvq->connected) {
58ada94f95f71d Vivek Goyal 2019-10-30 423 if (in_flight)
c17ea009610366 Vivek Goyal 2019-10-15 424 dec_in_flight_req(fsvq);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 425 kfree(forget);
58ada94f95f71d Vivek Goyal 2019-10-30 426 goto out;
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 427 }
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 428
1efcf39eb62757 Vivek Goyal 2019-10-30 429 sg_init_one(&sg, req, sizeof(*req));
58ada94f95f71d Vivek Goyal 2019-10-30 430 vq = fsvq->vq;
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 431 dev_dbg(&vq->vdev->dev, "%s\n", __func__);
58ada94f95f71d Vivek Goyal 2019-10-30 432
58ada94f95f71d Vivek Goyal 2019-10-30 433 ret = virtqueue_add_outbuf(vq, &sg, 1, forget, GFP_ATOMIC);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 434 if (ret < 0) {
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 435 if (ret == -ENOMEM || ret == -ENOSPC) {
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 436 pr_debug("virtio-fs: Could not queue FORGET: err=%d. Will try later\n",
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 437 ret);
58ada94f95f71d Vivek Goyal 2019-10-30 438 list_add_tail(&forget->list, &fsvq->queued_reqs);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 439 schedule_delayed_work(&fsvq->dispatch_work,
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 440 msecs_to_jiffies(1));
58ada94f95f71d Vivek Goyal 2019-10-30 441 if (!in_flight)
58ada94f95f71d Vivek Goyal 2019-10-30 442 inc_in_flight_req(fsvq);
58ada94f95f71d Vivek Goyal 2019-10-30 443 /* Queue is full */
58ada94f95f71d Vivek Goyal 2019-10-30 444 ret = 1;
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 445 } else {
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 446 pr_debug("virtio-fs: Could not queue FORGET: err=%d. Dropping it.\n",
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 447 ret);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 448 kfree(forget);
58ada94f95f71d Vivek Goyal 2019-10-30 449 if (in_flight)
58ada94f95f71d Vivek Goyal 2019-10-30 450 dec_in_flight_req(fsvq);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 451 }
58ada94f95f71d Vivek Goyal 2019-10-30 452 goto out;
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 453 }
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 454
58ada94f95f71d Vivek Goyal 2019-10-30 455 if (!in_flight)
58ada94f95f71d Vivek Goyal 2019-10-30 456 inc_in_flight_req(fsvq);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 457 notify = virtqueue_kick_prepare(vq);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 458 spin_unlock(&fsvq->lock);
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 459
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 460 if (notify)
a62a8ef9d97da2 Stefan Hajnoczi 2018-06-12 461 virtqueue_notify(vq);
58ada94f95f71d Vivek Goyal 2019-10-30 462 return ret;
58ada94f95f71d Vivek Goyal 2019-10-30 463 out:
58ada94f95f71d Vivek Goyal 2019-10-30 464 spin_unlock(&fsvq->lock);
58ada94f95f71d Vivek Goyal 2019-10-30 465 return ret;
58ada94f95f71d Vivek Goyal 2019-10-30 466 }
58ada94f95f71d Vivek Goyal 2019-10-30 467
--
0-DAY CI Kernel Test Service
https://01.org/lkp
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] virtiofs: Drop unnecessary initialization in send_forget_request and virtio_fs_get_tree
2022-09-06 5:38 [PATCH] virtiofs: Drop unnecessary initialization in send_forget_request and virtio_fs_get_tree Deming Wang
2022-09-06 10:10 ` kernel test robot
@ 2022-09-06 13:30 ` Stefan Hajnoczi
1 sibling, 0 replies; 3+ messages in thread
From: Stefan Hajnoczi @ 2022-09-06 13:30 UTC (permalink / raw)
To: Deming Wang; +Cc: vgoyal, miklos, virtualization, linux-fsdevel, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1624 bytes --]
On Tue, Sep 06, 2022 at 01:38:48AM -0400, Deming Wang wrote:
> The variable is initialized but it is only used after its assignment.
>
> Signed-off-by: Deming Wang <wangdeming@inspur.com>
> ---
> fs/fuse/virtio_fs.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
> index 4d8d4f16c..bffe74d44 100644
> --- a/fs/fuse/virtio_fs.c
> +++ b/fs/fuse/virtio_fs.c
> @@ -414,7 +414,7 @@ static int send_forget_request(struct virtio_fs_vq *fsvq,
> {
> struct scatterlist sg;
> struct virtqueue *vq;
> - int ret = 0;
> + int ret;
> bool notify;
> struct virtio_fs_forget_req *req = &forget->req;
>
That causes an uninitialized access in the source tree I'm looking at
(c5e4d5e99162ba8025d58a3af7ad103f155d2df7):
static int send_forget_request(struct virtio_fs_vq *fsvq,
struct virtio_fs_forget *forget,
bool in_flight)
{
struct scatterlist sg;
struct virtqueue *vq;
int ret = 0;
^^^^^^^
bool notify;
struct virtio_fs_forget_req *req = &forget->req;
spin_lock(&fsvq->lock);
if (!fsvq->connected) {
if (in_flight)
dec_in_flight_req(fsvq);
kfree(forget);
goto out;
...
out:
spin_unlock(&fsvq->lock);
return ret;
^^^
}
What is the purpose of this patch? Is there a compiler warning (if so,
which compiler and version)? Do you have a static analysis tool that
reported this (if yes, then maybe it's broken)?
Stefan
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^ permalink raw reply [flat|nested] 3+ messages in thread