Dear kexec team, I hope it is okay to ask you as my public problem description has not yielded any replies so far. My problem is posted here: http://unix.stackexchange.com/questions/237580/boot-rescue-kernel-at-high-me mory-address-using-kexec-on-arm and also copied below (without the formatting). Update: Same result when using kernel 4.3 and kexec-tools 2.0.11. Any help is highly appreciated, and thanks for the work you are putting into kexec! Best regards, Hans Heckel (Alcatel-Lucent, IP Routing and Transport) Summary: Crashkernel boots at 512MB address in RAM with kexec -l/-e but not with kexec -p - why? Embedded platform with Marvell Armada XP (MV78460) (ARMv7 with 4 cores) and 1GB of RAM. production kernel: customized Linux 3.4.91 rescue kernel: clean kernel.org-Linux (4.2.3) (I am aware that it uses device trees but that works fine by appending DTB to zImage) in user-space, I am using the latest kexec-tools (2.0.10) History: Using kexec -l (with ramdisk and command line params from 3.4.91-kernel, and --atags) and kexec -e, the rescue kernel boots just fine and seems to place itself in the beginning of RAM (according to /proc/iomem) regardless of what is being set via --mem-min and --mem-max. When reserving space in RAM using the boot-option crashkernel, I have to use a high memory address because otherwise it tells me the requested area is already in use. So we set crashkernel=128M at 512M. The kernel does not boot with kexec -p. Current status: I understand that relocatable kernels (CONFIG_AUTO_ZRELADDR=y) must reside within the top 128MB which is not possible for us. So I have worked around the standard kernel configuration and forced CONFIG_ARM_PATCH_PHYS_VIRT to no and CONFIG_PHYS_OFFSET to 0x20000000. I had to add a Makefile.boot for the machine where I set zreladdr-y := 0x20008000, params_phys-y := 0x20000100, initrd_phys-y := 0x20800000. Now the kernel still boots fine using kexec -l and kexec -e and according to --mem-min. I can see it is placed at 512MB. However, configuring it with -p and causing a panic, the console says "Loading crashdump kernel... Bye!" and remains silent forever. All files and everything is only located in RAM. What could I be doing wrong? Should I worry about the decompression errors (even in the good case)? >From dmesg: Reserving 128MB of memory at 512MB for crashkernel (System RAM: 760MB) root at host:~# cat /proc/iomem 00000000-3bff9fff : System RAM 00008000-00724f43 : Kernel code 0076e000-0087553f : Kernel data 20000000-27ffffff : Crash kernel (some RAM at the end is reserved for persistent storage, that's why it doesn't add up to 1GB) Successful case: root at host:~# kexec -l -t zImage --command-line="console=ttyS0,38400 earlyprintk=ttyS0 root=/dev/ram rdinit=/sbin/init rw irqpoll maxcpus=1 reset_devices" --atags --initrd=./initramfs.cpio.gz -d --mem-min=0x20000000 --mem-max=0x28000000 ./zImage_fixed_addr Try gzip decompression. Try LZMA decompression. lzma_decompress_file: read on ./zImage_fixed_addr of 65536 bytes failed kernel: 0xb6c06008 kernel_size: 0x3db659 kexec_load: entry = 0x20008000 flags = 0x280000 nr_segments = 3 segment[0].buf = 0x40e98 segment[0].bufsz = 0x3f0 segment[0].mem = 0x20001000 segment[0].memsz = 0x1000 segment[1].buf = 0xb6c06008 segment[1].bufsz = 0x3db659 segment[1].mem = 0x20008000 segment[1].memsz = 0x3dc000 segment[2].buf = 0xb5ade008 segment[2].bufsz = 0x1127516 segment[2].mem = 0x20f6e000 segment[2].memsz = 0x1128000 root at host:~# kexec -e Starting new kernel Booting Linux on physical CPU 0x0 ... After boot: root at vanilla:~# cat /proc/iomem 20000000-3fffffff : System RAM 20008000-206dd237 : Kernel code 20720000-2078f54f : Kernel data Unsuccessful case: root at host:~# kexec -p -t zImage --command-line="console=ttyS0,38400 earlyprintk=ttyS0 root=/dev/ram rdinit=/sbin/init rw irqpoll maxcpus=1 reset_devices" --atags --initrd=./initramfs.cpio.gz -d ./zImage_fixed_addr Try gzip decompression Try LZMA decompression. lzma_decompress_file: read on ./zImage_fixed_addr of 65536 bytes failed kernel: 0xb6b69008 kernel_size: 0x3db659 phys_offset: 0 kernel symbol _stext vaddr = c0008240 page_offset is set to c0000000 get_crash_notes_per_cpu: crash_notes addr = 10f525c, size = 1024 Elf header: p_type = 4, p_offset = 0x10f525c p_paddr = 0x10f525c p_vaddr = 0x0 p_filesz = 0x400 p_memsz = 0x400 get_crash_notes_per_cpu: crash_notes addr = 10ff25c, size = 1024 Elf header: p_type = 4, p_offset = 0x10ff25c p_paddr = 0x10ff25c p_vaddr = 0x0 p_filesz = 0x400 p_memsz = 0x400 get_crash_notes_per_cpu: crash_notes addr = 110925c, size = 1024 Elf header: p_type = 4, p_offset = 0x110925c p_paddr = 0x110925c p_vaddr = 0x0 p_filesz = 0x400 p_memsz = 0x400 get_crash_notes_per_cpu: crash_notes addr = 111325c, size = 1024 Elf header: p_type = 4, p_offset = 0x111325c p_paddr = 0x111325c p_vaddr = 0x0 p_filesz = 0x400 p_memsz = 0x400 vmcoreinfo header: p_type = 4, p_offset = 0x7f1330 p_paddr = 0x7f1330 p_vaddr = 0x0 p_filesz = 0x1000 p_memsz = 0x1000 Elf header: p_type = 1, p_offset = 0x0 p_paddr = 0x0 p_vaddr = 0xc0000000 p_filesz = 0x20000000 p_memsz = 0x20000000 Elf header: p_type = 1, p_offset = 0x28000000 p_paddr = 0x28000000 p_vaddr = 0xe8000000 p_filesz = 0x13ffa000 p_memsz = 0x13ffa000 elfcorehdr: 0x27f00000 crashkernel: [0x20000000 - 0x27ffffff] (128M) memory range: [0 - 0x1fffffff] (512M) memory range: [0x28000000 - 0x3bff9fff] (319M) kernel command line: "console=ttyS0,38400 earlyprintk=ttyS0 root=/dev/ram rdinit=/sbin/init rw irqpoll maxcpus=1 reset_devices elfcorehdr=0x27f00000 mem=130048K" kexec_load: entry = 0x20008000 flags = 0x280001 nr_segments = 4 segment[0].buf = 0x416e0 segment[0].bufsz = 0x410 segment[0].mem = 0x20001000 segment[0].memsz = 0x1000 segment[1].buf = 0xb6b69008 segment[1].bufsz = 0x3db659 segment[1].mem = 0x20008000 segment[1].memsz = 0x3dc000 segment[2].buf = 0xb5a41008 segment[2].bufsz = 0x1127516 segment[2].mem = 0x20f6e000 segment[2].memsz = 0x1128000 segment[3].buf = 0x412a0 segment[3].bufsz = 0x400 segment[3].mem = 0x27f00000 segment[3].memsz = 0x1000 <cause crash via SysRq> Loading crashdump kernel... 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