Clang warns:
drivers/block/rnbd/rnbd-srv.c:150:6: warning: variable 'err' is used
uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (IS_ERR(bio)) {
^~~~~~~~~~~
drivers/block/rnbd/rnbd-srv.c:177:9: note: uninitialized use occurs here
return err;
^~~
drivers/block/rnbd/rnbd-srv.c:126:9: note: initialize the variable 'err'
to silence this warning
int err;
^
= 0
Silence this by replacing `err` with `ret`, returning ret = 0 upon
success.
Signed-off-by: Brooke Basile <[email protected]>
---
drivers/block/rnbd/rnbd-srv.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index 0fb94843a495..f515d1a048a9 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -123,10 +123,10 @@ static int process_rdma(struct rtrs_srv *sess,
struct rnbd_io_private *priv;
struct rnbd_srv_sess_dev *sess_dev;
u32 dev_id;
- int err;
struct rnbd_dev_blk_io *io;
struct bio *bio;
short prio;
+ int ret = 0;
priv = kmalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
@@ -138,7 +138,7 @@ static int process_rdma(struct rtrs_srv *sess,
if (IS_ERR(sess_dev)) {
pr_err_ratelimited("Got I/O request on session %s for unknown device id %d\n",
srv_sess->sessname, dev_id);
- err = -ENOTCONN;
+ ret = -ENOTCONN;
goto err;
}
@@ -168,13 +168,13 @@ static int process_rdma(struct rtrs_srv *sess,
submit_bio(bio);
- return 0;
+ return ret;
sess_dev_put:
rnbd_put_sess_dev(sess_dev);
err:
kfree(priv);
- return err;
+ return ret;
}
static void destroy_device(struct rnbd_srv_dev *dev)
--
2.28.0
On Tue, Aug 18, 2020 at 12:03:18AM -0400, Brooke Basile wrote:
> Clang warns:
> drivers/block/rnbd/rnbd-srv.c:150:6: warning: variable 'err' is used
> uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
> if (IS_ERR(bio)) {
> ^~~~~~~~~~~
> drivers/block/rnbd/rnbd-srv.c:177:9: note: uninitialized use occurs here
> return err;
> ^~~
> drivers/block/rnbd/rnbd-srv.c:126:9: note: initialize the variable 'err'
> to silence this warning
> int err;
> ^
> = 0
>
> Silence this by replacing `err` with `ret`, returning ret = 0 upon
> success.
>
> Signed-off-by: Brooke Basile <[email protected]>
> ---
> drivers/block/rnbd/rnbd-srv.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
> index 0fb94843a495..f515d1a048a9 100644
> --- a/drivers/block/rnbd/rnbd-srv.c
> +++ b/drivers/block/rnbd/rnbd-srv.c
> @@ -123,10 +123,10 @@ static int process_rdma(struct rtrs_srv *sess,
> struct rnbd_io_private *priv;
> struct rnbd_srv_sess_dev *sess_dev;
> u32 dev_id;
> - int err;
> struct rnbd_dev_blk_io *io;
> struct bio *bio;
> short prio;
> + int ret = 0;
>
> priv = kmalloc(sizeof(*priv), GFP_KERNEL);
> if (!priv)
> @@ -138,7 +138,7 @@ static int process_rdma(struct rtrs_srv *sess,
> if (IS_ERR(sess_dev)) {
> pr_err_ratelimited("Got I/O request on session %s for unknown device id %d\n",
> srv_sess->sessname, dev_id);
> - err = -ENOTCONN;
> + ret = -ENOTCONN;
> goto err;
> }
>
> @@ -168,13 +168,13 @@ static int process_rdma(struct rtrs_srv *sess,
>
> submit_bio(bio);
>
> - return 0;
> + return ret;
>
> sess_dev_put:
> rnbd_put_sess_dev(sess_dev);
> err:
> kfree(priv);
> - return err;
> + return ret;
> }
>
> static void destroy_device(struct rnbd_srv_dev *dev)
> --
> 2.28.0
>
I don't think this is a proper fix since the root cause of the warning
appears to be that we are ignoring the return value of
rnbd_bio_map_kern. Should we not set err to that value like this
(completely untested)?
Cheers,
Nathan
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index 0fb94843a495..1b71cb2a885d 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -148,7 +148,8 @@ static int process_rdma(struct rtrs_srv *sess,
/* Generate bio with pages pointing to the rdma buffer */
bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, GFP_KERNEL);
if (IS_ERR(bio)) {
- rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", PTR_ERR(bio));
+ err = PTR_ERR(bio);
+ rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", err);
goto sess_dev_put;
}
On Tue, Aug 18, 2020 at 7:30 AM Nathan Chancellor
<[email protected]> wrote:
>
> On Tue, Aug 18, 2020 at 12:03:18AM -0400, Brooke Basile wrote:
> > Clang warns:
> > drivers/block/rnbd/rnbd-srv.c:150:6: warning: variable 'err' is used
> > uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
> > if (IS_ERR(bio)) {
> > ^~~~~~~~~~~
> > drivers/block/rnbd/rnbd-srv.c:177:9: note: uninitialized use occurs here
> > return err;
> > ^~~
> > drivers/block/rnbd/rnbd-srv.c:126:9: note: initialize the variable 'err'
> > to silence this warning
> > int err;
> > ^
> > = 0
> >
> > Silence this by replacing `err` with `ret`, returning ret = 0 upon
> > success.
> >
> > Signed-off-by: Brooke Basile <[email protected]>
> > ---
> > drivers/block/rnbd/rnbd-srv.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
> > index 0fb94843a495..f515d1a048a9 100644
> > --- a/drivers/block/rnbd/rnbd-srv.c
> > +++ b/drivers/block/rnbd/rnbd-srv.c
> > @@ -123,10 +123,10 @@ static int process_rdma(struct rtrs_srv *sess,
> > struct rnbd_io_private *priv;
> > struct rnbd_srv_sess_dev *sess_dev;
> > u32 dev_id;
> > - int err;
> > struct rnbd_dev_blk_io *io;
> > struct bio *bio;
> > short prio;
> > + int ret = 0;
> >
> > priv = kmalloc(sizeof(*priv), GFP_KERNEL);
> > if (!priv)
> > @@ -138,7 +138,7 @@ static int process_rdma(struct rtrs_srv *sess,
> > if (IS_ERR(sess_dev)) {
> > pr_err_ratelimited("Got I/O request on session %s for unknown device id %d\n",
> > srv_sess->sessname, dev_id);
> > - err = -ENOTCONN;
> > + ret = -ENOTCONN;
> > goto err;
> > }
> >
> > @@ -168,13 +168,13 @@ static int process_rdma(struct rtrs_srv *sess,
> >
> > submit_bio(bio);
> >
> > - return 0;
> > + return ret;
> >
> > sess_dev_put:
> > rnbd_put_sess_dev(sess_dev);
> > err:
> > kfree(priv);
> > - return err;
> > + return ret;
> > }
> >
> > static void destroy_device(struct rnbd_srv_dev *dev)
> > --
> > 2.28.0
> >
>
> I don't think this is a proper fix since the root cause of the warning
> appears to be that we are ignoring the return value of
> rnbd_bio_map_kern. Should we not set err to that value like this
> (completely untested)?
>
> Cheers,
> Nathan
Thanks Nathan, thanks Brooke,
I agree with Nathan, the problem is we forgot to set the err before
"goto sess_dev_put".
Nathan's patch is simpler, less code of change.
>
> diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
> index 0fb94843a495..1b71cb2a885d 100644
> --- a/drivers/block/rnbd/rnbd-srv.c
> +++ b/drivers/block/rnbd/rnbd-srv.c
> @@ -148,7 +148,8 @@ static int process_rdma(struct rtrs_srv *sess,
> /* Generate bio with pages pointing to the rdma buffer */
> bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, GFP_KERNEL);
> if (IS_ERR(bio)) {
> - rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", PTR_ERR(bio));
> + err = PTR_ERR(bio);
> + rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", err);
> goto sess_dev_put;
> }
>
Nathan, could you send a formal patch?
Thanks
Clang warns:
drivers/block/rnbd/rnbd-srv.c:150:6: warning: variable 'err' is used
uninitialized whenever 'if' condition is true
[-Wsometimes-uninitialized]
if (IS_ERR(bio)) {
^~~~~~~~~~~
drivers/block/rnbd/rnbd-srv.c:177:9: note: uninitialized use occurs here
return err;
^~~
drivers/block/rnbd/rnbd-srv.c:150:2: note: remove the 'if' if its
condition is always false
if (IS_ERR(bio)) {
^~~~~~~~~~~~~~~~~~
drivers/block/rnbd/rnbd-srv.c:126:9: note: initialize the variable 'err'
to silence this warning
int err;
^
= 0
1 warning generated.
err is indeed uninitialized when this statement is taken. Ensure that it
is assigned the error value of bio before jumping to the error handling
label.
Fixes: 735d77d4fd28 ("rnbd: remove rnbd_dev_submit_io")
Link: https://github.com/ClangBuiltLinux/linux/issues/1134
Reported-by: Brooke Basile <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
---
drivers/block/rnbd/rnbd-srv.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index 0fb94843a495..1b71cb2a885d 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -148,7 +148,8 @@ static int process_rdma(struct rtrs_srv *sess,
/* Generate bio with pages pointing to the rdma buffer */
bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, GFP_KERNEL);
if (IS_ERR(bio)) {
- rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", PTR_ERR(bio));
+ err = PTR_ERR(bio);
+ rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", err);
goto sess_dev_put;
}
--
2.28.0
On Tue, Aug 18, 2020 at 8:50 AM Nathan Chancellor
<[email protected]> wrote:
>
> Clang warns:
>
> drivers/block/rnbd/rnbd-srv.c:150:6: warning: variable 'err' is used
> uninitialized whenever 'if' condition is true
> [-Wsometimes-uninitialized]
> if (IS_ERR(bio)) {
> ^~~~~~~~~~~
> drivers/block/rnbd/rnbd-srv.c:177:9: note: uninitialized use occurs here
> return err;
> ^~~
> drivers/block/rnbd/rnbd-srv.c:150:2: note: remove the 'if' if its
> condition is always false
> if (IS_ERR(bio)) {
> ^~~~~~~~~~~~~~~~~~
> drivers/block/rnbd/rnbd-srv.c:126:9: note: initialize the variable 'err'
> to silence this warning
> int err;
> ^
> = 0
> 1 warning generated.
>
> err is indeed uninitialized when this statement is taken. Ensure that it
> is assigned the error value of bio before jumping to the error handling
> label.
>
> Fixes: 735d77d4fd28 ("rnbd: remove rnbd_dev_submit_io")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1134
> Reported-by: Brooke Basile <[email protected]>
> Signed-off-by: Nathan Chancellor <[email protected]>
Thanks!
Acked-by: Jack Wang <[email protected]>
> ---
> drivers/block/rnbd/rnbd-srv.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
> index 0fb94843a495..1b71cb2a885d 100644
> --- a/drivers/block/rnbd/rnbd-srv.c
> +++ b/drivers/block/rnbd/rnbd-srv.c
> @@ -148,7 +148,8 @@ static int process_rdma(struct rtrs_srv *sess,
> /* Generate bio with pages pointing to the rdma buffer */
> bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, GFP_KERNEL);
> if (IS_ERR(bio)) {
> - rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", PTR_ERR(bio));
> + err = PTR_ERR(bio);
> + rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", err);
> goto sess_dev_put;
> }
>
> --
> 2.28.0
>
On 8/18/20 1:29 AM, Nathan Chancellor wrote:
> I don't think this is a proper fix since the root cause of the warning
> appears to be that we are ignoring the return value of
> rnbd_bio_map_kern. Should we not set err to that value like this
> (completely untested)?
>
> Cheers,
> Nathan
>
> diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
> index 0fb94843a495..1b71cb2a885d 100644
> --- a/drivers/block/rnbd/rnbd-srv.c
> +++ b/drivers/block/rnbd/rnbd-srv.c
> @@ -148,7 +148,8 @@ static int process_rdma(struct rtrs_srv *sess,
> /* Generate bio with pages pointing to the rdma buffer */
> bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, GFP_KERNEL);
> if (IS_ERR(bio)) {
> - rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", PTR_ERR(bio));
> + err = PTR_ERR(bio);
> + rnbd_srv_err(sess_dev, "Failed to generate bio, err: %ld\n", err);
> goto sess_dev_put;
> }
>
>
Ah, I see what you mean. Thanks for the fix!
Best,
Brooke Basile
On 8/17/20 11:49 PM, Nathan Chancellor wrote:
> Clang warns:
>
> drivers/block/rnbd/rnbd-srv.c:150:6: warning: variable 'err' is used
> uninitialized whenever 'if' condition is true
> [-Wsometimes-uninitialized]
> if (IS_ERR(bio)) {
> ^~~~~~~~~~~
> drivers/block/rnbd/rnbd-srv.c:177:9: note: uninitialized use occurs here
> return err;
> ^~~
> drivers/block/rnbd/rnbd-srv.c:150:2: note: remove the 'if' if its
> condition is always false
> if (IS_ERR(bio)) {
> ^~~~~~~~~~~~~~~~~~
> drivers/block/rnbd/rnbd-srv.c:126:9: note: initialize the variable 'err'
> to silence this warning
> int err;
> ^
> = 0
> 1 warning generated.
>
> err is indeed uninitialized when this statement is taken. Ensure that it
> is assigned the error value of bio before jumping to the error handling
> label.
Applied, thanks.
--
Jens Axboe