Re: [PATCH v3 0/1] kernel: kprobes: fix cur_kprobe corruption during re-entrant kprobe_busy_begin() calls

[Khaja Hussain Shaik Khaji]

On Mon, Mar 02, 2026 at 04:23:46PM +0530, Mark Rutland wrote:
> The el1_dbg() function was removed in commit:
>
>   31575e11ecf7 ("arm64: debug: split brk64 exception entry")
>
> ... which was merged in v6.17.
>
> Are you able to reproduce the issue with v6.17 or later?
>
> Which specific kernel version did you see this with?

The call trace was captured on v6.9-rc1.

I have not yet tested on v6.17 or later. I will test and report back.

That said, the fix is in kernel/kprobes.c and addresses a generic
re-entrancy issue in kprobe_busy_begin/end that is not specific to the
arm64 entry path. The race -- where kprobe_busy_begin() is called
re-entrantly from within an active kprobe context (e.g. via softirq
during kretprobe entry_handler) -- can occur on any architecture where
IRQs are re-enabled before invoking kprobe handlers.

I will verify whether the issue is still reproducible on v6.17+ and
report back.

Thanks,
Khaja