Re: stable-rc build: 72 warnings 1 failures (stable-rc/v4.4.30-35-gf821e08)

[Arnd Bergmann <arnd@arndb.de>]

On Tuesday, November 8, 2016 9:16:28 AM CET Olof's autobuilder wrote:
> Here are the build results from automated periodic testing.
> 
> The tree being built was stable-rc, found at:
> 
> https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable-rc.git/
> 
> Topmost commit:
> 
> f821e08 Linux 4.4.31-rc1
> 
> Build logs (stderr only) can be found at the following link (experimental):
> 
> http://arm-soc.lixom.net/buildlogs/stable-rc/v4.4.30-35-gf821e08/

These seem to be largely caused by building with gcc-6. It's probably
a good idea to keep supporting that configuration though and
backport the fixes. Here are the upstream commit IDs I've found.

> -------------------------------------------------------------------------------
> 
> Failed defconfigs:
> 	powerpc.pasemi_defconfig
> 
> -------------------------------------------------------------------------------
> 
> Errors:
> 
> 	powerpc.pasemi_defconfig:
> /work/build/batch/arch/powerpc/kernel/ptrace.c:378:104: error: index 32 denotes an offset greater than size of 'u64[32][1] {aka long long unsigned int[32][1]}' [-Werror=array-bounds]
> /work/build/batch/arch/powerpc/kernel/ptrace.c:406:104: error: index 32 denotes an offset greater than size of 'u64[32][1] {aka long long unsigned int[32][1]}' [-Werror=array-bounds]

1e407ee3b21f ("powerpc/ptrace: Fix out of bounds array access warning")


> Warnings:
> 
>       1 drivers/block/floppy.c:1777:44: warning: self-comparison always evaluates to true [-Wtautological-compare]
>       1 drivers/block/floppy.c:1779:44: warning: self-comparison always evaluates to true [-Wtautological-compare]
>       1 drivers/block/floppy.c:4479:45: warning: self-comparison always evaluates to true [-Wtautological-compare]
>       1 drivers/block/floppy.c:4487:45: warning: self-comparison always evaluates to true [-Wtautological-compare]

dd665be0e243 ("ARM: 8584/1: floppy: avoid gcc-6 warning")

>       1 drivers/of/of_reserved_mem.c:131:180: warning: comparison of distinct pointer types lacks a cast
>       1 drivers/of/of_reserved_mem.c:131:182: warning: comparison of distinct pointer types lacks a cast
>       1 drivers/of/of_reserved_mem.c:131:364: warning: comparison of distinct pointer types lacks a cast
>       1 drivers/of/of_reserved_mem.c:131:368: warning: comparison of distinct pointer types lacks a cast

aaaab56dba9a ("of: silence warnings due to max() usage")

>       1 fs/devpts/inode.c:462:23: warning: self-comparison always evaluates to false [-Wtautological-compare]

I think this was accidentally fixed by eedf265aa003 ("devpts: Make each mount of
devpts an independent filesystem."), which unfortunately is not a candidate for stable

>       1 kernel/sched/core.c:2941:26: warning: calling '__builtin_return_address' with a nonzero argument is unsafe [-Wframe-address]
>       1 kernel/sched/core.c:2943:27: warning: calling '__builtin_return_address' with a nonzero argument is unsafe [-Wframe-address]

A number of patches went in for this one, the last one was

ef6000b4c670 ("Disable the __builtin_return_address() warning globally after all")


>       1 mm/cma.c:186:131: warning: comparison of distinct pointer types lacks a cast
>       1 mm/cma.c:269:193: warning: comparison of distinct pointer types lacks a cast
>       1 mm/cma.c:269:379: warning: comparison of distinct pointer types lacks a cast

badbda53e505 ("mm/cma: silence warnings due to max() usage")

>       1 net/netfilter/xt_owner.c:27:23: warning: self-comparison always evaluates to false [-Wtautological-compare]

Apparently also fixed as a side-effect of a larger patch:

9847371a84b0 ("netfilter: Allow xt_owner in any user namespace")

This one might be appropriate for a stable backport, Eric Biederman
would know for sure.

>       4 drivers/gpu/drm/exynos/exynos_drm_core.c:104:199: warning: self-comparison always evaluates to false [-Wtautological-compare]

55c4b906aa2a ("drm/exynos: fix error handling in exynos_drm_subdrv_open")

>       4 drivers/i2c/busses/i2c-imx.c:1007:10: warning: 'return' with a value, in function returning void

The same one showed up in linux-4.8.y-rc earlier today and is now gone, I assume
it was already fixed there.

>       9 kernel/cgroup.c:239:396: warning: array subscript is above array bounds [-Warray-bounds]

cfe02a8a973e ("cgroup: avoid false positive gcc-6 warning")

>      19 drivers/net/ethernet/smsc/smc91x.c:563:14: warning: self-comparison always evaluates to true [-Wtautological-compare]

e3ebd894f084 ("smc91x: avoid self-comparison warning")

>       1 include/uapi/linux/swab.h:14:33: warning: integer overflow in expression [-Woverflow]
>       5 kernel/audit.c:663:22: warning: self-comparison always evaluates to false [-Wtautological-compare]
>       6 kernel/taskstats.c:289:22: warning: self-comparison always evaluates to false [-Wtautological-compare]
>       4 drivers/connector/cn_proc.c:349:23: warning: self-comparison always evaluates to false [-Wtautological-compare]
>       2 fs/xfs/xfs_ioctl.c:1166:22: warning: self-comparison always evaluates to true [-Wtautological-compare]


No idea.

	Arnd