Hi, could I have a review of this patch. This patch fixes [JDK-8391637](https://bugs.openjdk.org/browse/JDK-8391637).
On `risc-v`, [LinuxRISCV64CFrame.sender()](https://github.com/openjdk/jdk/blob/c368bac40e185398fbc40dc4d75a457f7a36f954/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/linux/riscv64/LinuxRISCV64CFrame.java#L70) validates only FP alignment, then dereferences FP for SP, link, and return address. An aligned arbitrary FP (such as 0x90) can therefore cause UnmappedAddressException, and lead to incomplete stack for the target thread. `aarch64` and `amdf64`already use `dwarf` to unwind native frames, see https://github.com/openjdk/jdk/blob/c368bac40e185398fbc40dc4d75a457f7a36f954/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/linux/amd64/LinuxAMD64CFrame.java#L36 https://github.com/openjdk/jdk/blob/c368bac40e185398fbc40dc4d75a457f7a36f954/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/linux/aarch64/LinuxAARCH64CFrame.java#L38 This patch makes `risc-v` to unwind with `dwarf` too. The `risc-v` version basically has the same design as the `aarch64` version. There are also several differences , primarily due to differences in calling conventions. Almost every difference is accompanied by an explanatory comment. I have ran tests in `test/hotspot/jtreg/serviceability/sa` on `risc-v` and `amd64`, all passed. --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - Add comment - 8391637: On the RISC-V platform, TestJhsdbJstackMixed has a certain probability of failure Changes: https://git.openjdk.org/jdk/pull/33358/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=33358&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8391637 Stats: 393 lines in 11 files changed: 308 ins; 23 del; 62 mod Patch: https://git.openjdk.org/jdk/pull/33358.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/33358/head:pull/33358 PR: https://git.openjdk.org/jdk/pull/33358
