RFR: 8283306: re-resolving indirect call to non-entrant nmethod can crash

[Tom Rodriguez]

On Wed, 4 May 2022 07:47:28 GMT, Dean Long <dlong at openjdk.org> wrote:

> This change fixes a crash that can happen in SharedRuntime::reresolve_call_site with Graal/JVMCI.
> See https://bugs.openjdk.java.net/browse/JDK-8283306 for details.

I think a formulation more like this makes it clearer.  I'm not sure I agree with the assert/guarantee in the default path since it seems overly specific.

    if (call_addr != NULL) {
      // On x86 the logic for finding a call instruction is blindly checking for a call opcode 5
      // bytes back in the instruction stream so we must also check for reloc info.
      RelocIterator iter(caller_nm, call_addr, call_addr+1);
      int ret = iter.next(); // Get item
      if (ret) {
        bool is_static_call = false;
        switch (iter.type()) {
          case relocInfo::static_call_type:
            is_static_call = true;

          case relocInfo::virtual_call_type:
          case relocInfo::opt_virtual_call_type:
            // Cleaning the inline cache will force a new resolve. This is more robust
            // than directly setting it to the new destination, since resolving of calls
            // is always done through the same code path. (experience shows that it
            // leads to very hard to track down bugs, if an inline cache gets updated
            // to a wrong method). It should not be performance critical, since the
            // resolve is only done once.
            guarantee(iter.addr() == call_addr, "must find call");
            for (;;) {
              ICRefillVerifier ic_refill_verifier;
              if (!clear_ic_at_addr(caller_nm, call_addr, is_static_call)) {
                InlineCacheBuffer::refill_ic_stubs();
              } else {
                break;
              }
            }
            break;
          default:
            guarantee(!UseInlineCaches || caller_nm->is_compiled_by_jvmci(), "relocation info. must exist for this address");
        }
      }
    }

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PR: https://git.openjdk.java.net/jdk/pull/8528