Re: [dpdk-dev] [PATCH v3 00/40] Fix build on gcc8 and various bugs

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, May 10, 2018 at 01:35:49PM +0100, Luca Boccassi wrote:
> On Thu, 2018-05-10 at 20:23 +0800, Andy Green wrote:
> > 
> > On 05/10/2018 06:21 PM, Luca Boccassi wrote:
> > > On Thu, 2018-05-10 at 10:46 +0800, Andy Green wrote:
> > > > The following series gets current master able to build
> > > > itself, and allow lagopus to build against it, on Fedora 28 +
> > > > x86_64 using gcc 8.0.1.
> > > > 
> > > > The first 17 patches have already been through two spins and
> > > > this time are corrected for all the comment (thanks to
> > > > everybody who commented) since v2, and have tested-by /
> > > > acked-bys applied.  The first workaround patch for the hash
> > > > function cast problem is dropped since something has already
> > > > been applied in master since yesterday to address it.
> > > > 
> > > > The additional 23 patches are fixes for problems found
> > > > actually trying to build lagopus using current master.
> > > > These are almost entirely related to signed / unsigned
> > > > or truncation without explicit casts inside dpdk
> > > > headers.
> > > > 
> > > > ---
> > > > 
> > > > Andy Green (40):
> > > >        drivers/bus/pci: fix strncpy dangerous code
> > > >        drivers/bus/dpaa: fix inconsistent struct alignment
> > > >        drivers/net/axgbe: fix broken eeprom string comp
> > > >        drivers/net/nfp/nfpcore: fix strncpy misuse
> > > >        drivers/net/nfp/nfpcore: fix off-by-one and no NUL on
> > > > strncpy
> > > > use
> > > >        drivers/net/nfp: don't memcpy out of source range
> > > >        drivers/net/nfp: fix buffer overflow in fw_name
> > > >        drivers/net/qede: fix strncpy constant and NUL
> > > >        drivers/net/qede: fix broken strncpy
> > > >        drivers/net/sfc: fix strncpy length
> > > >        drivers/net/sfc: fix strncpy size and NUL
> > > >        drivers/net/vdev: readlink inputs cannot be aliased
> > > >        drivers/net/vdev: fix 3 x strncpy misuse
> > > >        app/test-pmd: can't find include
> > > >        app/proc-info: fix sprintf overrun bug
> > > >        app/test-bbdev: test-bbdev: strcpy ok for allocated string
> > > >        app/test-bbdev: strcpy ok for allocated string
> > > >        rte_common.h: cast gcc builtin result to avoid complaints
> > > >        rte_memcpy.h: explicit tmp cast
> > > >        lib/librte_eal/common/include/rte_lcore.h: explicit cast
> > > > for
> > > > signed change
> > > >        /lib/librte_eal/common/include/rte_random.h: stage cast
> > > > from
> > > > uint64_t to long
> > > >        rte_spinlock.h: stack declarations before code
> > > >        rte_ring_generic.h: stack declarations before code
> > > >        rte_ring.h: remove signed type flipflopping
> > > >        rte_dev.h: stack declaration at top of own basic block
> > > >        rte_mbuf.h: avoid truncation warnings from inadvertant
> > > > int16_t
> > > > to int promotion
> > > >        rte_mbuf.h: explicit casts for flipping between int16_t
> > > > and
> > > > uint16_t
> > > >        rte_mbuf.h: make sure RTE_MIN compares same types
> > > >        rte_mbuf.h: explicit cast restricting ptrdiff to uint16_t
> > > >        rte_mbuf.h: explicit cast for size_t to uint32_t
> > > >        rte_mbuf.h: explicit casts to uint16_t to avoid truncation
> > > > warnings
> > > >        rte_byteorder.h: explicit cast for return promotion
> > > >        rte_ether.h: explicit cast avoiding truncation warning
> > > >        rte_ether.h: stack vars declared at top of function
> > > >        rte_ethdev.h: fix sign and scope of temp var
> > > >        rte_ethdev.h: explicit cast for return type
> > > >        rte_ethdev.h: explicit cast for truncation
> > > >        rte_hash_crc.h: stack vars declared at top of function
> > > >        rte_hash_crc.h: explicit casts for truncation
> > > >        rte_string_fns.h: explicit cast for int return to size_t
> > > 
> > > Hi,
> > > 
> > > I've built-tested this series on Debian Stretch (gcc 6.3) and
> > > Debian
> > > Sid (gcc 8.1).
> > > 
> > > The series builds fine with the default config, but the bnx2x and
> > > mlx5
> > > PMDs still have errors with gcc-8:
> > 
> > Yes I just built it with defconfig for x86_64 on Fedora 28 with
> > default 
> > tools and cleared out everything that came up.
> > 
> > > /tmp/dpdk/drivers/net/bnx2x/bnx2x.c: In function
> > > 'bnx2x_alloc_hsi_mem':
> > > /tmp/dpdk/drivers/net/bnx2x/bnx2x.c:176:29: error: '%s' directive
> > > writing up to 31 bytes into a region of size between 15 and 25 [-
> > > Werror=format-overflow=]
> > >     sprintf(mz_name, "bnx2x%d_%s_%" PRIx64, sc->pcie_device, msg,
> > >                               ^~
> > > /tmp/dpdk/drivers/net/bnx2x/bnx2x.c:8874:7:
> > >     if (bnx2x_dma_alloc(sc, sizeof(union
> > > bnx2x_host_hc_status_block),
> > >         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > ~~
> > >         &fp->sb_dma, buf, RTE_CACHE_LINE_SIZE) != 0) {
> > >         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > /tmp/dpdk/drivers/net/bnx2x/bnx2x.c:176:3: note: 'sprintf' output
> > > between 10 and 66 bytes into a destination of size 32
> > >     sprintf(mz_name, "bnx2x%d_%s_%" PRIx64, sc->pcie_device, msg,
> > >     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >      rte_get_timer_cycles());
> > >      ~~~~~~~~~~~~~~~~~~~~~~~
> > > /tmp/dpdk/drivers/net/bnx2x/bnx2x.c:173:29: error: '%s' directive
> > > writing up to 31 bytes into a region of size between 23 and 25 [-
> > > Werror=format-overflow=]
> > >     sprintf(mz_name, "bnx2x%d_%s_%" PRIx64, SC_ABS_FUNC(sc), msg,
> > >                               ^~
> > > /tmp/dpdk/drivers/net/bnx2x/bnx2x.c:8874:7:
> > >     if (bnx2x_dma_alloc(sc, sizeof(union
> > > bnx2x_host_hc_status_block),
> > >         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > ~~
> > >         &fp->sb_dma, buf, RTE_CACHE_LINE_SIZE) != 0) {
> > >         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > /tmp/dpdk/drivers/net/bnx2x/bnx2x.c:173:3: note: 'sprintf' output
> > > between 10 and 58 bytes into a destination of size 32
> > >     sprintf(mz_name, "bnx2x%d_%s_%" PRIx64, SC_ABS_FUNC(sc), msg,
> > >     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >      rte_get_timer_cycles());
> > > 
> > > 
> > > /tmp/dpdk/drivers/net/mlx5/mlx5.c: In function 'mlx5_pci_probe':
> > > /tmp/dpdk/drivers/net/mlx5/mlx5.c:920:13: error: 'vf' may be used
> > > uninitialized in this function [-Werror=maybe-uninitialized]
> > >     config.vf = vf;
> > > 
> > > Hope this can be useful.
> > 
> > I think gcc 8.0.1 is capable to show that and I am willing to look
> > at 
> > them.  But can you help me with exactly what changes you made so
> > these 
> > things built and made trouble, compared to the defconfig I have used 
> > until now?
> 
> If you already have a build directory you are using, the simplest way
> is to edit the .config file in there and change the following from =n
> to =y:
> 
> CONFIG_RTE_LIBRTE_MLX4_PMD
> CONFIG_RTE_LIBRTE_MLX5_PMD
> CONFIG_RTE_LIBRTE_BNX2X_PMD
> 
> Then rebuild and you should see the errors.
> 
Personally, though I wouldn't view it as necessary to get those extra fixes
into this set. The set is big enough as it is, so I'd like to see the
existing gcc 8 fixes we have merged to make some progress, rather than
constantly spinning ever bigger sets to try and fix them all in one go.

My 2c.

/Bruce