Re: modinfo crc32 broken after fd44a98ae2eb

[Samson Yeung <samson.yeung@oracle.com>]

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On 01/28/2016 11:21 AM, Lucas De Marchi wrote:
> Hi Samson,
>
> On Wed, Jan 27, 2016 at 5:32 PM, Samson Yeung <samson.yeung@oracle.com> wrote:
>> Hi all,
>>
>> Please reply directly as I am not on this list.
>>
>> Commit "fd44a98ae2eb Fix race while loading modules" also broke 'modinfo
>> crc32', specifically, for me.
>>
>> Is this a bug, is it something strange going on with crc32, or is it
>> intended behavior?
>
> breaking is never intended ;-). What do you mean by "break"? Does it crash?

'modinfo crc32' prints

modinfo: ERROR: Module crc32 not found.

and a return value of 1 using fd44a98ae2eb.

Without changing the contents of /lib/modules/`uname -r`/modules.* 
files, using fd44a98ae2eb^, 'modinfo crc32' gives me the expected info 
about crc32 instead:

filename:       /lib/modules/4.2.0-25-generic/kernel/crypto/crc32.ko
alias:          crypto-crc32
alias:          crc32
license:        GPL
description:    CRC32 calculations wrapper for lib/crc32
author:         Alexander Boyko <alexander_boyko@xyratex.com>
srcversion:     B0DE005719AC9ED9A3EEAD7
depends:
intree:         Y
vermagic:       4.2.0-25-generic SMP mod_unload modversions
signer:         Build time autogenerated kernel key
sig_key:        A4:10:30:FB:DF:1D:C9:62:B4:BB:7D:16:44:C3:33:7E:C4:16:DB:86
sig_hashalgo:   sha512

> I can't see how this commit is related to modinfo. You will need to
> give more details. Check if you can get the output by passing the
> complete path to the module and make sure it's actually a module (and

Giving the full path to the module still works as expected, so
'modinfo /lib/modules/4.2.0-25-generic/kernel/crypto/crc32.ko' displays 
module information and returns 0, using both fd44a98ae2eb^ and fd44a98ae2eb.

> not builtin) in your kernel configuration

I must admit that I'm slightly confused wrt crc32, since there is 
kernel/arch/x86/crypto/crc32-pclmul.ko as well as 
kernel/crypto/crc32.ko, and 'modinfo crc32-pclmul' claims that crc32 is 
an alias.

I This happens with a stock Ubuntu kernel (4.2.0-25-generic for Wily), 
however I first observed this behavior on Redhat/Oracle Linux 7.

> Lucas De Marchi

I have attached a slightly more complete log demonstrating the issue.


Regards,
-Samson

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fragmede@biem:((tags/v20~8))~/tmp/kmod/git/kernel.org/kmod.git$ git checkout fd44a98ae2eb^ && ./autogen.sh >/dev/null && ./configure >/dev/null && make -j `nproc` >/dev/null && ./tools/modinfo crc32
Previous HEAD position was fd44a98ae2eb... Fix race while loading modules
HEAD is now at fae77516b405... build: we are kmod, not systemd
ar: `u' modifier ignored since `D' is the default (see `U')
filename:       /lib/modules/4.2.0-25-generic/kernel/crypto/crc32.ko
alias:          crypto-crc32
alias:          crc32
license:        GPL
description:    CRC32 calculations wrapper for lib/crc32
author:         Alexander Boyko <alexander_boyko@xyratex.com>
srcversion:     B0DE005719AC9ED9A3EEAD7
depends:        
intree:         Y
vermagic:       4.2.0-25-generic SMP mod_unload modversions 
signer:         Build time autogenerated kernel key
sig_key:        A4:10:30:FB:DF:1D:C9:62:B4:BB:7D:16:44:C3:33:7E:C4:16:DB:86
sig_hashalgo:   sha512
fragmede@biem:((tags/v20~9))~/tmp/kmod/git/kernel.org/kmod.git$ git checkout fd44a98ae2eb && ./autogen.sh >/dev/null && ./configure >/dev/null && make -j `nproc` >/dev/null && ./tools/modinfo crc32
Previous HEAD position was fae77516b405... build: we are kmod, not systemd
HEAD is now at fd44a98ae2eb... Fix race while loading modules
ar: `u' modifier ignored since `D' is the default (see `U')
modinfo: ERROR: Module crc32 not found.
fragmede@biem:((tags/v20~8))~/tmp/kmod/git/kernel.org/kmod.git$