[dpdk-dev] 回复: [dpdk-stable] [PATCH] crypto/qat: fix uninitilized compiler warning

[Feifei Wang <Feifei.Wang2@arm.com>]

Hi, David

> -----邮件原件-----
> 发件人: David Marchand <david.marchand@redhat.com>
> 发送时间: 2021年5月14日 15:50
> 收件人: Feifei Wang <Feifei.Wang2@arm.com>
> 抄送: John Griffin <john.griffin@intel.com>; Fiona Trahe
> <fiona.trahe@intel.com>; Deepak Kumar Jain <deepak.k.jain@intel.com>;
> Herbert Guan <Herbert.Guan@arm.com>; Jerin Jacob
> <jerin.jacob@caviumnetworks.com>; dev <dev@dpdk.org>; nd
> <nd@arm.com>; dpdk stable <stable@dpdk.org>; Ruifeng Wang
> <Ruifeng.Wang@arm.com>
> 主题: Re: [dpdk-stable] [PATCH] crypto/qat: fix uninitilized compiler warning
> 
> On Fri, May 14, 2021 at 9:41 AM Feifei Wang <feifei.wang2@arm.com> wrote:
> >
> > In Arm platform, when "RTE_ARCH_ARM64_MEMCPY" is set as true,
> compiler
> > will report variable uninitilized warning:
> >
> > ../drivers/crypto/qat/qat_sym_session.c: In function
> ‘partial_hash_compute’:
> > ../lib/eal/include/generic/rte_byteorder.h:241:24: warning:
> > ‘<U35a0>’ may be used uninitialized in this function
> >         [-Wmaybe-uninitialized]
> >         241 | #define rte_bswap32(x) __builtin_bswap32(x)
> >         ...
> >
> > This is because "digest" will be initialized by "rte_memcpy" function
> > rather than "memcpy" if "RTE_ARCH_ARM64_MEMCPY" is set as true.
> > However, compiler cannot know it is initialized by the function.
> >
> > To fix this, use "calloc" to initialize "digest".
> >
> > Fixes: cd7fc8a84b48 ("eal/arm64: optimize memcpy")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > ---
> >  drivers/crypto/qat/qat_sym_session.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/crypto/qat/qat_sym_session.c
> > b/drivers/crypto/qat/qat_sym_session.c
> > index 231b1640da..dab23a3290 100644
> > --- a/drivers/crypto/qat/qat_sym_session.c
> > +++ b/drivers/crypto/qat/qat_sym_session.c
> > @@ -1190,8 +1190,8 @@ static int partial_hash_compute(enum
> icp_qat_hw_auth_algo hash_alg,
> >                         uint8_t *data_out)  {
> >         int digest_size;
> > -       uint8_t digest[qat_hash_get_digest_size(
> > -                       ICP_QAT_HW_AUTH_ALGO_DELIMITER)];
> > +       uint8_t *digest = (uint8_t *)calloc(qat_hash_get_digest_size(
> > +                               ICP_QAT_HW_AUTH_ALGO_DELIMITER),
> > + sizeof(uint8_t));
> 
> calloc can fail.
> cast is unneded.
> 
> A simple uint8_t digest[...] = { 0 } would do the job.

Thanks for your comment. Actually, we have tried to use this simple method:
 uint8_t digest[qat_hash_get_digest_size(ICP_QAT_HW_AUTH_ALGO_DELIMITER)] = {0};

And it will report compile error:
../drivers/crypto/qat/qat_sym_session.c:1194:4: error: variable-sized object may not be initialized
 1194 |    ICP_QAT_HW_AUTH_ALGO_DELIMITER)] = {0};
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/crypto/qat/qat_sym_session.c:1194:40: warning: excess elements in array initializer
 1194 |    ICP_QAT_HW_AUTH_ALGO_DELIMITER)] = {0};
      |                                        ^
../drivers/crypto/qat/qat_sym_session.c:1194:40: note: (near initialization for ‘digest’)
ninja: build stopped: subcommand failed.

I think this is because compiler cannot know the size of digest due to function
'qat_hash_get_digest_size' during  compiling time.

Best Regards
Feifei
> 
> 
> >         uint32_t *hash_state_out_be32;
> >         uint64_t *hash_state_out_be64;
> >         int i;
> > --
> > 2.25.1
> >
> 
> 
> 
> --
> David Marchand