Re: [PATCH 05/12] s390: zcrypt: initialize variables before_use

Martin Schwidefsky
2019-04-10T15:59:46Z

On Tue, 9 Apr 2019 11:54:30 +0200
Harald Freudenberger <freude@linux.ibm.com> wrote:

> On 08.04.19 23:26, Arnd Bergmann wrote:
> > The 'func_code' variable gets printed in debug statements without
> > a prior initialization in multiple functions, as reported when building
> > with clang:
> >
> > drivers/s390/crypto/zcrypt_api.c:659:6: warning: variable 'func_code' is used uninitialized whenever 'if' condition is true
> > [-Wsometimes-uninitialized]
> > if (mex->outputdatalength < mex->inputdatalength) {
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > drivers/s390/crypto/zcrypt_api.c:725:29: note: uninitialized use occurs here
> > trace_s390_zcrypt_rep(mex, func_code, rc,
> > ^~~~~~~~~
> > drivers/s390/crypto/zcrypt_api.c:659:2: note: remove the 'if' if its condition is always false
> > if (mex->outputdatalength < mex->inputdatalength) {
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > drivers/s390/crypto/zcrypt_api.c:654:24: note: initialize the variable 'func_code' to silence this warning
> > unsigned int func_code;
> > ^
> >
> > Add initializations to all affected code paths to shut up the warning
> > and make the warning output consistent.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > drivers/s390/crypto/zcrypt_api.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/s390/crypto/zcrypt_api.c b/drivers/s390/crypto/zcrypt_api.c
> > index eb93c2d27d0a..23472063d9a8 100644
> > --- a/drivers/s390/crypto/zcrypt_api.c
> > +++ b/drivers/s390/crypto/zcrypt_api.c
> > @@ -657,6 +657,7 @@ static long zcrypt_rsa_modexpo(struct ap_perms *perms,
> > trace_s390_zcrypt_req(mex, TP_ICARSAMODEXPO);
> >
> > if (mex->outputdatalength < mex->inputdatalength) {
> > + func_code = -1;
> > rc = -EINVAL;
> > goto out;
> > }
> > @@ -739,6 +740,7 @@ static long zcrypt_rsa_crt(struct ap_perms *perms,
> > trace_s390_zcrypt_req(crt, TP_ICARSACRT);
> >
> > if (crt->outputdatalength < crt->inputdatalength) {
> > + func_code = -1;
> > rc = -EINVAL;
> > goto out;
> > }
> > @@ -946,6 +948,7 @@ static long zcrypt_send_ep11_cprb(struct ap_perms *perms,
> >
> > targets = kcalloc(target_num, sizeof(*targets), GFP_KERNEL);
> > if (!targets) {
> > + func_code = -1;
> > rc = -ENOMEM;
> > goto out;
> > }
> > @@ -953,6 +956,7 @@ static long zcrypt_send_ep11_cprb(struct ap_perms *perms,
> > uptr = (struct ep11_target_dev __force __user *) xcrb->targets;
> > if (copy_from_user(targets, uptr,
> > target_num * sizeof(*targets))) {
> > + func_code = -1;
> > rc = -EFAULT;
> > goto out_free;
> > }
> Thanks Arnd, but as Nathan already wrote, I'd prefer to have the
> variable initialized with 0 instead of -1.
> If you agree with this, I'll rewrite the patch and apply it to our
> internal git and it will appear at kernel org with the next s390 code merge then.

Do we agreement on func_coed=0 for this one ?

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.