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Re: [Crash-utility] [PATCH] Endian-mismatch: crash shows a contrary error message





于 2014/9/30 22:08, Dave Anderson 写道:


----- Original Message -----
When the vmcore or vmlinux is not the same endian with the host,
crash will give out a error message to show that mismatching, but
the message itself is not correct.
This patch fix that logical bug.

Interesting -- I've never been able to actually test this until now -- with
a ppc64/ppc64le combination.  I'm guessing you saw this on a big-endian
32-bit ARM?


Yes, the kdump file i used was generated by a network device -- a big-endian 32-bit ARM board.

As we all known, the network byte order is big-endian, so we chose to use the same byte order on the network device. Actually, almost all the network devices are big-endian.

Unfortunately, CRASH is not support big-endian yet. I've added some codes to make it to pass through the init routines and make some commands say, kmem -i, ps, log, etc. works.

It seems to me that you are interested about the big-endian enabled.But the pathes are all too rough, so I havn't sent them out yet.For example, when CRASH wants to use a unsigned long variable, it will first use readmem() to get that, what I did was just make some reverse before using it.

There is a discussion -- "gdb on KDUMP files" -- on the mailing list. I have been considering something similar with that these days.If we can use gdb to read the memory, the byte-order-problem will never be a problem again, because gdb can change byte order automatically, meanwhile it can change the byte order by sending a command "set endian big(small/auto)".

Thanks,
    Hu Keping


Good catch -- queued for crash-7.0.9:

   https://github.com/crash-utility/crash/commit/5b78ac40710048705108cbd2e44d2ddc4cf71d72

Thanks,
   Dave



Signed-off-by: Hu Keping <hukeping huawei com>
---
  tools.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools.c b/tools.c
index 4ff3fd5..cb684b1 100644
--- a/tools.c
+++ b/tools.c
@@ -5515,12 +5515,12 @@ endian_mismatch(char *file, char dumpfile_endian,
ulong query)
  	case ELFDATA2LSB:
  		if (__BYTE_ORDER == __LITTLE_ENDIAN)
  			return FALSE;
-		endian = "big-endian";
+		endian = "little-endian";
  		break;
  	case ELFDATA2MSB:
  		if (__BYTE_ORDER == __BIG_ENDIAN)
  			return FALSE;
-		endian = "little-endian";
+		endian = "big-endian";
  		break;
  	default:
  		endian = "unknown";
--
1.8.5.5



.



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