Re: [PATCH v8 1/4] fs/proc/kcore: avoid bounce buffer for ktext data

Lorenzo Stoakes
2023-07-31T21:58:19Z

On Mon, Jul 31, 2023 at 11:50:22PM +0200, Jiri Olsa wrote:
> > Ummmm what? I can't! What repro are you seeing on x86, exactly?
>
> # cat /proc/kallsyms | grep ksys_read
> ffffffff8151e450 T ksys_read
>
> # objdump -d --start-address=0xffffffff8151e450 --stop-address=0xffffffff8151e460 /proc/kcore
>
> /proc/kcore: file format elf64-x86-64
>
> objdump: Reading section load1 failed because: Bad address
>
>
> jirka

Locally I don't see this issue. How odd. The bug doesn't manifest as a 'bad
address' in the arm64 repros either. I wonder if this is something unrelated...

In any case I have a candidate fix for the bug at
https://lore.kernel.org/all/20230731215021.70911-1-lstoakes@gmail.com/ which
should hopefully address the underlying issue with minimum change.