Re: [PATCH 0/5] arm64: add kdump support

From: AKASHI Takahiro
Date: Thu Apr 02 2015 - 03:49:08 EST


On 04/02/2015 03:01 PM, Pratyush Anand wrote:


On Thursday 02 April 2015 11:07 AM, AKASHI Takahiro wrote:
Pratyush,

On 04/02/2015 01:58 PM, Pratyush Anand wrote:


On Thursday 02 April 2015 04:57 AM, AKASHI Takahiro wrote:
Please try my latest kexec-tools in my linaro repo (branch name is
kdump/v0.11)
and let me know the result.

Thanks a lot.. Just fetched your repo and found v.0.11.

With this crash kernel loaded successfully, if I do not use initrd.

With following I still see Overlapping memory segments

kexec -p /home/panand/work/kernel/bsa2_kdump/vmlinux
--initrd=/boot/initramfs-3.19.0.bz1198945+.img --append="$( cat
/proc/cmdline ) maxcpus=1 mem=64M reset_devices"

How big is your initrd?
If it is good small, please tell me segments info, or messages from
add_segment_phys_virt()
for all the segments.


add_segment_phys_virt: 000000000dcd0b90 - 000000000dcd0f90 (00000400) -> 00000040c3ff0000 - 00000040c4000000 (00010000)
add_segment_phys_virt: 000003ff88c10010 - 000003ff8984a010 (00c3a000) -> 00000040c0080000 - 00000040c1310000 (01290000)
add_segment_phys_virt: 000000000dcd53c0 - 000000000dcd96b8 (000042f8) -> 00000040c0000000 - 00000040c0010000 (00010000)
add_segment_phys_virt: 000003ff87360010 - 000003ff88bfcc2f (0189cc1f) -> 00000040c0010000 - 00000040c18b0000 (018a0000)
Overlapping memory segments at 0x40c18b0000
sort_segments failed

Why do we try to fit dtb just after crash_reserved_mem.start. Should n't it should start after crash_reserved_mem.start
+ arm64_mem.text_offset + arm64_mem.image_size

Yeah, worth considering :)

-Takahiro AKASHI


I tried following and it works perfectly:

diff --git a/kexec/arch/arm64/crashdump-arm64.c b/kexec/arch/arm64/crashdump-arm64.c
index 41266f294589..75f4e4d269ca 100644
--- a/kexec/arch/arm64/crashdump-arm64.c
+++ b/kexec/arch/arm64/crashdump-arm64.c
@@ -312,5 +312,6 @@ void set_crash_entry(struct mem_ehdr *ehdr, struct kexec_info *info)
off_t locate_dtb_in_crashmem(struct kexec_info *info, off_t dtb_size)
{
return locate_hole(info, dtb_size, 128UL * 1024,
- crash_reserved_mem.start, crash_reserved_mem.end, 1);
+ crash_reserved_mem.start + arm64_mem.text_offset +
+ arm64_mem.image_size, crash_reserved_mem.end, 1);
}

With this changes new allocations are:
add_segment_phys_virt: 0000000010350b90 - 0000000010350f90 (00000400) -> 00000040c3ff0000 - 00000040c4000000 (00010000)
add_segment_phys_virt: 000003ff7ad70010 - 000003ff7b9aa010 (00c3a000) -> 00000040c0080000 - 00000040c1310000 (01290000)
add_segment_phys_virt: 00000000103553c0 - 00000000103596b8 (000042f8) -> 00000040c1360000 - 00000040c1370000 (00010000)
add_segment_phys_virt: 000003ff794c0010 - 000003ff7ad5cc2f (0189cc1f) -> 00000040c1370000 - 00000040c2c10000 (018a0000)
add_segment_phys_virt: 00000000103596c0 - 0000000010360190 (00006ad0) -> 00000040c2c10000 - 00000040c2c20000 (00010000)


Crash kernel loaded upon panic.

~Pratyush
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