RFR: 8259937: guarantee(loc != NULL) failed: missing saved register with native invoker

[Vladimir Kozlov]

On Thu, 11 Feb 2021 15:31:11 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> We spotted this issue with Shenandoah and I managed to write a simple
> test case that reproduces it reliably with Shenandoah but the issue is
> independent of the GC.
> 
> The loop in the test case calls a native invoker with an oop live in
> rbp. rbp is saved in the native invoker stub's frame. A safepoint is
> triggered from the safepoint check in the native invoker. The stack
> walking code sees that rbp contains an oop but can't find where that
> oop is stored. That's because stack walking updates the caller's frame
> with the location of rbp in the callee on calls to
> frame::sender(). But the current code sets the last java frame to be
> the compiled frame where rbp is live. So there's no call to
> frame::sender() to update the location rbp. The fix I propose is that
> the frame of the native invoker be visible by stack walking. On a
> safepoint, stack walking starts from the native invoker thread, then
> calls frame::sender() to move to the compiled frame. That causes rbp
> to be properly recorded with its location in the native invoker frame.
> 
> Same problem affects both x86 and aarch64. I've tested this patch with:
> 
> make run-test TEST="java/foreign" TEST_VM_OPTS="-Xcomp" JTREG="TIMEOUT_FACTOR=10"
> 
> on both platforms.

Seems reasonable.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/2528