kernel kdump support

[vincentmli]

https://docs.kernel.org/admin-guide/kdump/kdump.html

Fedora kexec-tools package has kdump user space component on loading kdump kernel but it is designed for Fedora with systemd in mind, need to borrow some of the Fedora kexec-tools package and use in bpfire/loongfire.

[vincentmli]

the kdump user space tool kdumpctrl depends on makedumpfile binary so makedumpfile needs to be built and installed separately, get error below when building makedumpfile, makedumpfile Makefile is using libdw.a and libelf.a in linker for static build, but BPFire libdw.a and libelf.a is not build with zstd, so modify makedumpfile Makefile not to build statically as workaround by comment out the static section:

#ifneq ($(LINKTYPE), dynamic)
#LIBS := -static $(LIBS) -llzma
#endif

error while build makedumpfile statically

makedumpfile (1.7.7)                                                                     [        6 ][ FAIL ]

    cc -O2 -pipe -Wall -fexceptions -fPIC -m64 -mtune=generic -fcf-protection=full -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fstack-protector-strong -fstack-clash-protection -g -O2 -Wall -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D__x86_64__  -c -o ./arch/loongarch64.o arch/loongarch64.c
    cc -O2 -pipe -Wall -fexceptions -fPIC -m64 -mtune=generic -fcf-protection=full -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fstack-protector-strong -fstack-clash-protection -g -O2 -Wall -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D__x86_64__  -c -o ./arch/riscv64.o arch/riscv64.c
    cc -O2 -pipe -Wall -fexceptions -fPIC -m64 -mtune=generic -fcf-protection=full -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fstack-protector-strong -fstack-clash-protection -g -O2 -Wall -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DVERSION='"1.7.7"' -DRELEASE_DATE='"21 Apr 2025"' -D__x86_64__   print_info.o dwarf_info.o elf_info.o erase_info.o sadump_info.o cache.o tools.o printk.o detect_cycle.o arch/arm.o arch/arm64.o arch/x86.o arch/x86_64.o arch/ia64.o arch/ppc64.o arch/s390x.o arch/ppc.o arch/sparc64.o arch/mips64.o arch/loongarch64.o arch/riscv64.o -rdynamic -o makedumpfile makedumpfile.c -static -ldw -lbz2 -ldl -lelf -lz -llzma -lpthread
    /usr/bin/ld: erase_info.o: in function `process_eppic_file':
    /usr/src/makedumpfile-1.7.7/erase_info.c:2200:(.text+0x38a9): warning: Using 'dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
    /usr/bin/ld: /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.0/../../../../lib64/libdw.a(zstd.o): in function `__libdw_unzstd':
    zstd.c:(.text+0x104): undefined reference to `ZSTD_createDCtx'
    /usr/bin/ld: zstd.c:(.text+0x155): undefined reference to `ZSTD_isError'
    /usr/bin/ld: zstd.c:(.text+0x1e0): undefined reference to `ZSTD_decompressStream'
    /usr/bin/ld: zstd.c:(.text+0x1eb): undefined reference to `ZSTD_isError'
    /usr/bin/ld: zstd.c:(.text+0x22d): undefined reference to `ZSTD_freeDCtx'
    /usr/bin/ld: zstd.c:(.text+0x235): undefined reference to `ZSTD_isError'
    /usr/bin/ld: zstd.c:(.text+0x38c): undefined reference to `ZSTD_freeDCtx'
    /usr/bin/ld: /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.0/../../../../lib64/libelf.a(elf_compress.o): in function `__libelf_compress':
    elf_compress.c:(.text+0xff): undefined reference to `ZSTD_createCCtx'
    /usr/bin/ld: elf_compress.c:(.text+0x284): undefined reference to `ZSTD_compressStream2'
    /usr/bin/ld: elf_compress.c:(.text+0x28f): undefined reference to `ZSTD_isError'
    /usr/bin/ld: elf_compress.c:(.text+0x2b9): undefined reference to `ZSTD_freeCCtx'
    /usr/bin/ld: elf_compress.c:(.text+0x531): undefined reference to `ZSTD_freeCCtx'
    /usr/bin/ld: elf_compress.c:(.text+0x669): undefined reference to `ZSTD_freeCCtx'
    /usr/bin/ld: elf_compress.c:(.text+0x737): undefined reference to `ZSTD_freeCCtx'
    /usr/bin/ld: elf_compress.c:(.text+0x78d): undefined reference to `ZSTD_freeCCtx'
    /usr/bin/ld: /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.0/../../../../lib64/libelf.a(elf_compress.o):elf_compress.c:(.text+0x7f0): more undefined references to `ZSTD_freeCCtx' follow
    /usr/bin/ld: /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.0/../../../../lib64/libelf.a(elf_compress.o): in function `__libelf_decompress':
    elf_compress.c:(.text+0x9c3): undefined reference to `ZSTD_decompress'
    /usr/bin/ld: elf_compress.c:(.text+0x9cb): undefined reference to `ZSTD_isError'
    collect2: error: ld returned 1 exit status
    make[1]: *** [Makefile:116: makedumpfile] Error 1
    make[1]: Leaving directory '/usr/src/makedumpfile-1.7.7'
    make: *** [makedumpfile:74: /usr/src/log/makedumpfile-1.7.7] Error 2

ERROR: Building makedumpfile                                                                         [ FAIL ]
    Check /home/vincent/go/src/github.com/vincentmli/BPFire/log/_build.ipfire.log for errors if appli[ FAIL ]

[vincentmli]

#ifneq ($(LINKTYPE), dynamic)
#LIBS := -static $(LIBS) -llzma
#endif

actually from https://github.com/makedumpfile/makedumpfile FAQ, we can use make LINKTYPE=dynamic to build dynamic makedumpfile, but if the capture kernel boot without root partition mounted, dynamic makedumpfile may not have the required shared libelf.so available, keep this in mind, maybe eventually we need to build a static makedumpfile

[vincentmli]

adjust kdump-config for BPFire initramfs

root@r210:/usr/src/kdump-tools-1.10.7/debian# diff -u kdump-config.in  kdump-config
--- kdump-config.in	2025-08-16 20:16:43.509794171 +0000
+++ kdump-config	2025-08-17 17:04:29.579677472 +0000
@@ -585,8 +585,8 @@
 		else
 			KDUMP_KERNEL=
 		fi
-		if [ -f "/boot/initrd.img-$KVER" ]; then
-			KDUMP_INITRD=/boot/initrd.img-$KVER
+		if [ -f "/boot/initramfs-$KVER.img" ]; then
+			KDUMP_INITRD=/boot/initramfs-$KVER.img
 		else
 			KDUMP_INITRD=
 		fi

initial test:

[root@bpfire init.d]# kdump-config load
cp: cannot stat '/etc/kdump/sysctl.conf': No such file or directory
Creating symlink /var/lib/kdump/vmlinuz.
ln: failed to create symbolic link '/var/lib/kdump/vmlinuz': No such file or directory
Unable to locate kernel hook ... failed!
Memory for crashkernel is not reserved
Please reserve memory by passing"crashkernel=Y@X" parameter to kernel
Then try to loading kdump kernel
failed to load kdump kernel ... failed!

we may need to create /etc/kdump directory in bpfire, copy sysctl.conf to /etc/kdump, adjust grup to use crashkernel=Y@X instead of crashkernel=auto