[Crash-utility] [PATCH 2/2] memory_driver: Support overriding kernel directory

[lijiang]

On Thu, Sep 28, 2023 at 2:50 AM Mathias Krause <minipli at grsecurity.net>
wrote:

> Hi Lianbo,
>
> Thanks for testing! My response is inline below...
>
> On 27.09.23 11:14, lijiang wrote:
> > Hi, Mathias
> > Thank you for the patchset.
> > On Tue, Sep 26, 2023 at 10:36 PM <crash-utility-request at redhat.com
> > <mailto:crash-utility-request at redhat.com>> wrote:
> >
> >     Date: Tue, 26 Sep 2023 12:12:47 +0200
> >     From: Mathias Krause <minipli at grsecurity.net
> >     <mailto:minipli at grsecurity.net>>
> >     To: crash-utility at redhat.com <mailto:crash-utility at redhat.com>
> >     Subject: [Crash-utility] [PATCH 2/2] memory_driver: Support
> overriding
> >             kernel directory
> >     Message-ID: <20230926101247.1237748-3-minipli at grsecurity.net
> >     <mailto:20230926101247.1237748-3-minipli at grsecurity.net>>
> >     Content-Type: text/plain; charset="US-ASCII"; x-default=true
> >
> >     Support compiling the module against a different kernel version than
> the
> >     currently running one by allowing to set either KVER or KDIR
> variables
> >     on the make commandline.
> >
> >     Also modernize the makefile slightly and make use of the kernel's
> >     'clean' target to ensure to remove all generated files.
> >
> >
> > The [PATCH 1/2] looks good to me.
>
> Thanks.
>
> >
> > For the [PATCH 2/2], I only have two questions:
> >
> > [1] With the patch 2/2, it always triggers recompiling the gdb like this:
> > # make lzo
> > TARGET: PPC64
> >  CRASH: 8.0.3++
> >    GDB: 10.2
> >
> >   CXX    gdb.o
> >   CXX    ../../crash_target.o
> >   CXX    ada-exp.o
> >   CXX    ada-lang.o
> >   CXX    ada-tasks.o
> >   CXX    ada-typeprint.o
> >   CXX    ada-valprint.o
> >   CXX    ada-varobj.o
> >   CXX    addrmap.o
> >   CXX    agent.o
> >   CXX    alloc.o
> >   CXX    annotate.o
> > ...
>
> Hmm, I cannot reproduce this. If I do 'make lzo' it builds 'crash' only
> once, not multiple times as you're observing. Can you please provide
> instructions how to reproduce the issue? Or, maybe, it's related to the
> second one...
>
>
This issue still exists with the v2:
https://listman.redhat.com/archives/crash-utility/2023-September/011021.html


I can reproduce it with the following steps(require kernel-devel package):

[1] make lzo
[2] make clean
[3] make lzo(or make warn)
# make lzo
TARGET: ARM64
 CRASH: 8.0.3++
   GDB: 10.2

  CXX    gdb.o
  CXX    ../../crash_target.o
  CXX    aarch32-linux-nat.o
  CXX    aarch32-tdep.o
  CXX    aarch64-linux-nat.o
  CXX    aarch64-linux-tdep.o
  CXX    aarch64-ravenscar-thread.o
  CXX    aarch64-tdep.o
...

# make warn
TARGET: ARM64
 CRASH: 8.0.3++
   GDB: 10.2

  CXX    gdb.o
  CXX    ../../crash_target.o
  CXX    aarch32-linux-nat.o
  CXX    aarch32-tdep.o
  CXX    aarch64-linux-nat.o
  CXX    aarch64-linux-tdep.o
  CXX    aarch64-ravenscar-thread.o
  CXX    aarch64-tdep.o
...

>
> > [2] With the patch 2/2, it always reports the following error "No such
> > file or directory", if the kernel-devel package is not installed.
> > # make clean
> > ...
> > make -C /lib/modules/xxx/build M=/home/crash SUBDIRS=/home/crash clean
> > || rm -f *.mod.c *.ko *.o Module.*
> > make[3]: *** /lib/modules/xxx/build: No such file or directory.  Stop.
> >
> > Actually, I did not build the crash.ko in the directory memory_driver/.
> >
> > Is that expected behavior?
>
> Ahh, yes. That's expected, but unfortunate behavior. I'll fix it by
> testing if the build directory exists first to avoid the error message.
>
> The fall-back handling is already there -- simply does the old 'rm
> *.mod.c *.ko *.o Module.*'. However, there's no need to generate an
> error message when we know in advance that the kernel build directory is
> missing.
>

With the v2, this issue disappeared.

Thanks.
Lianbo
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/crash-utility/attachments/20230928/e2b32bf6/attachment.htm>