Re: [Crash-utility] [PATCH 2/2] memory_driver: Support overriding kernel directory
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(a)redhat.com
<mailto:crash-utility-request@redhat.com>> wrote:
Date: Tue, 26 Sep 2023 12:12:47 +0200
From: Mathias Krause <minipli(a)grsecurity.net
<mailto:minipli@grsecurity.net>>
To: crash-utility(a)redhat.com <mailto:crash-utility@redhat.com>
Subject: [Crash-utility] [PATCH 2/2] memory_driver: Support overriding
kernel directory
Message-ID: <20230926101247.1237748-3-minipli(a)grsecurity.net
<mailto:20230926101247.1237748-3-minipli@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...
[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.
I'll send v2 in a moment.
Thanks,
Mathias
Thanks
Lianbo
Signed-off-by: Mathias Krause <minipli(a)grsecurity.net
<mailto:minipli@grsecurity.net>>
---
memory_driver/Makefile | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/memory_driver/Makefile b/memory_driver/Makefile
index b494aa3cd184..b720661fa75f 100644
--- a/memory_driver/Makefile
+++ b/memory_driver/Makefile
@@ -8,8 +8,13 @@
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
+ifneq ($(KERNELRELEASE),)
obj-m := crash.o
+else
+KVER ?= $(shell uname -r)
+KDIR ?= /lib/modules/${KVER}/build
all:
- make -C /lib/modules/`uname -r`/build M=${PWD}
SUBDIRS=${PWD} modules
+ ${MAKE} -C ${KDIR} M=${PWD} SUBDIRS=${PWD} modules
clean:
- rm -f *.mod.c *.ko *.o Module.*
+ ${MAKE} -C ${KDIR} M=${PWD} SUBDIRS=${PWD} clean || ${RM}
*.mod.c *.ko *.o Module.*
+endif
--
2.30.2