Re: [Crash-utility] [PATCH] fix command vm/files -d/mount on new kernel
----- Original Message -----
----- Original Message -----
> Hello Dave,
>
> New kernel has moved some elements of struct vfsmount to a new struct
> mount. So crash will not act normally on new kernel. The patch is used
> to fix the problem.
>
> Please check.
Hi Qiao,
This patch-set is very much appreciated. I saw Al Viro's original LKML patch
posted back in December (?), and had been waiting to see an actual kernel with
it in place. The most recent in-house RHEL/Fedora test kernels I have on-hand
are all 3.2.x-era kernels, which don't have the patch, so I'm presuming
you're
running on a 3.3.x kernel?
Anyway, I'll check this patch out for backwards-compatibility and try to
get a more recent kernel to test with. It looks good on paper...
And again, thanks for taking on this task.
Dave
I provisioned a system with a Fedora 3.3.0-0.rc6.git2.1.fc17 kernel, which
has the vfsmount->mount patch. The session comes up cleanly, but the
following commands fail:
crash> mount
... [ cut ] ...
mount: invalid structure member offset: vfsmount_mnt_list
...
crash> files
... [cut] ...
files: invalid structure member offset: dentry_d_covers
...
The "fuser" command generates the above error because it uses the
"files" command behind the scenes.
crash> vm
... [cut] ...
vm: invalid structure member offset: dentry_d_covers
...
crash> swap
... [cut] ...
swap: invalid structure member offset: dentry_d_covers
...
With your patch applied, "mount", "files", "fuser" and
"vm" all
work OK.
But "swap" now fails in a different manner:
crash> swap
FILENAME TYPE SIZE USED PCT PRIORITY
swap: invalid kernel virtual address: 1d8ec8 type: "fill_dentry_cache"
crash>
It's failing in its call to get_pathname(). I haven't had a chance to
fully check into why it's getting a bogus parent dentry address
while walking through the swap file's
"/dev/mapper/vg_dellpec610002-lv_swap"
pathname -- and I won't be able to until next week. But presumably it's
related, and so if you (or anybody) gets a chance this weekend, please
take a look.
Thanks,
Dave