On 7/1/2026 9:43 PM, Masami Hiramatsu wrote:

On Wed, 1 Jul 2026 12:14:54 +0000
Pu Hu [off-list ref] wrote:

quoted

From: hupu <redacted>

This series fixes two arm64 kprobes issues observed when running
simpleperf with preemptirq tracepoints and dwarf callchains while a
kprobe is active on a frequently executed kernel function.

The crash happens in the kprobe debug exception path. While a kprobe is
preparing or executing its XOL single-step instruction, perf/trace code
can run in the same window. That code may either take a fault of its own
or hit another kprobe.

Patch 1 makes kprobe_fault_handler() handle a fault in
KPROBE_HIT_SS/KPROBE_REENTER only when the faulting PC points at the
current kprobe's XOL instruction. Otherwise the fault is left to the
normal fault handling path.

Patch 2 allows a kprobe hit in KPROBE_HIT_SS to be handled as a
recoverable one-level reentry. Only a hit while already in
KPROBE_REENTER remains unrecoverable.

This follows the same logic as the existing x86 fixes:
   6381c24cd6d5 ("kprobes/x86: Fix page-fault handling logic")
   6a5022a56ac3 ("kprobes/x86: Allow to handle reentered kprobe on single-stepping")

Good catch!!
The series looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

But it should be reviewed by arm64 maintainers too.

BTW, if you are "Pu Hu", the Signed-off-by tag should be
"Pu Hu <...>" instead of "hupu <...>".

Hi Masami,

Thank you for your reply and Acked-by.

Yes, thanks for pointing this out. I will fix the author name and the
Signed-off-by tags to use a consistent name in the next version of the
patchset.

Thanks,
hupu