Re: Regression in 028abd92 for Sun UltraSPARC T1

[Frank Scheiner <frank.scheiner@web.de>]

On 24.03.21 09:28, Christoph Hellwig wrote:
> On Tue, Mar 23, 2021 at 11:17:41PM +0100, Frank Scheiner wrote:
>> 028abd9222df0cf5855dab5014a5ebaf06f90565
>>
>> ...is broken on my T1000.
>>
>> As I don't know how big attachments can be on this list, I put the logs
>> on pastebin.
>>
>> A log for 028abd9222df is here:
>>
>> https://pastebin.com/ApPYsMcu
>
> Just do confirm:  in this tree line 304 in mm/slub.c is this BUG_ON:
>
> 	BUG_ON(object == fp); /* naive detection of double free or corruption */
>
> which would mean we have a double free.  In that case it would be
> interesting which call to kfree this is, which could be done by
> calling gdb on vmlinux and then typing;
>
> l *(sys_mount+0x114/0x1e0)
>
> Not that a double free caused by this conversion makes any sense to me..

This is what I get:

```
root@t1000:~/kernels-in-question# gdb vmlinux-028abd9222df-new
GNU gdb (Debian 9.2-1+b1) 9.2
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "sparc64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
     <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from vmlinux-028abd9222df-new...
(gdb) l *(sys_mount+0x114/0x1e0)
0x6c6380 is in __se_sys_mount (fs/namespace.c:3390).
3385	fs/namespace.c: No such file or directory.
(gdb)
```

Kernel sources are not available on the T1000.

If need be, where do they need to exist and how should the directory be
named - `/usr/src/[...]`?

Cheers,
Frank