Re: [PATCH v6 0/7] riscv: Add reliable stack unwinding for livepatch

Thus wrote Shuai Xue (xueshuai@linux.alibaba.com):

Hi,

This is v6 of the RISC-V reliable stack unwinding series for livepatch.
Wang Han has left our team, so I am taking over this series from now on.

The series adds explicit frame-record metadata, preserves the frame
pointer through dynamic ftrace, and replaces the open-coded stack walker
with a conservative frame-pointer based unwinder. It then enables the
RISC-V livepatch capability and adds the syscall-wrapper selftest prefix.

Changes since v5:
* Rebase onto the current riscv/for-next; no functional changes.
* Fold in the tags collected from the v5 thread:
  - Reviewed-by: Shuai Xue on 2/7, 3/7, 4/7 and 6/7
  - Acked-by: Miroslav Benes on 7/7
* Add my sign-off as the new sender.

Since the patches are otherwise identical to v5, the v5 validation
results still apply. For reference, from the v5 cover letter:
* Built Linux 7.2.0-rc6 with riscv64-unknown-linux-gnu-gcc 15.2.0
  and binutils 2.46.
* Standard livepatch configuration built successfully, including
  Image, vmlinux, modules, compile_commands.json and GDB scripts.
* CONFIG_IRQ_STACKS=n variant linked successfully with GCC.
* QEMU 8.2.2, 1 CPU: livepatch selftests PASS: 7, SKIP: 1,
  FAIL: 0; ftrace function graph 3 passed, 0 failed, 3 unsupported.
* QEMU 8.2.2, 4 CPUs: livepatch selftests PASS: 7, SKIP: 1,
  FAIL: 0; ftrace function graph 3 passed, 0 failed, 3 unsupported.
* No BUG, WARNING, Oops, panic, unreliable stack or Call Trace found
  by the validation log scans. Expected negative livepatch errors are
  part of the selftests.

v5 was posted in early August and has been quiet since then. I would
appreciate it if the series could be considered for the upcoming merge
window. Happy to address any remaining feedback.

Base:
riscv/for-next 77ae27fd98f3 ("Merge tag 'printk-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux")

Previous versions:
v5: https://lore.kernel.org/r/20260804103626.2803112-1-wanghan@linux.alibaba.com (local)
v4 RESEND: https://lore.kernel.org/r/20260629072713.3273743-1-wanghan@linux.alibaba.com (local)
v3: https://lore.kernel.org/r/cover.194d76e3a15b.v3.riscv-livepatch.wanghan@linux.alibaba.com (local)
v2: https://lore.kernel.org/r/20260528082310.1994388-1-wanghan@linux.alibaba.com (local)
v1: https://lore.kernel.org/r/20260527123530.2593918-1-wanghan@linux.alibaba.com (local)

Assisted-by: Qoder:Qwen-3.8-MAX-Preview

Thanks for these patches.

I tried them on a standard rv64 qemu and on a rv64 cheri system
(cheri-linux.org). The latter needed some minor tweaks, but in
both cases, I could get livepatch to work.

Reviewed-by: Martin Kaiser <redacted>
Tested-by: Martin Kaiser <redacted>