JDK-4454110 : Need to deal gracefully with unsafe operations that access invalid memory
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 1.4.0
  • Priority: P3
  • Status: Closed
  • Resolution: Duplicate
  • OS: generic
  • CPU: generic
  • Submitted: 2001-05-03
  • Updated: 2001-06-22
  • Resolved: 2001-06-22
Related Reports
Duplicate :  
JDK-4454115 - Need to deal gracefully with unsafe operations that access invalid memory (C2)
Relates :  
JDK-4454113 - Need to deal gracefully with unsafe operations that access invalid memory (C1)
Relates :  
JDK-6244515 - Unsafe operations that access invalid memory are not handled gracefully
Description
I'm submitting this per a conversation earlier today with gri and kbr.

HotSpot needs to deal more gracefully with SIGSEGV, SIGBUS, and similar OS
events that occur when an unsafe get or put operation accesses invalid memory.
Whether such an invocation returns zero, returns an arbitrary value, or throws
an exception doesn't really matter -- the important thing is to avoid crashing
the VM.

This is required by NIO in order to support memory-mapped files.

I'm filing related bugs under both C1 and C2.

-- mr@eng 2001/5/3
Comments
EVALUATION Personal communications with John Rose: Robert G indicated that you are working on/have fixed this bug, which has to do with unexpected signals while accessing memory-mapped files. Is this done for C2, and is there any work outside of C2 and C2 (i.e., in the runtime) that needs to be done? No, I think it's done. You'll find the runtime work in the baseline, in my recent delta to os_solaris_<arch>.cpp. robertg@east 2001-06-22
22-06-2001
SUGGESTED FIX John Rose already fixed this. See bug 4455115, which is the C2-specific version of the fix. Note that his fix also fixed the C1-specific problem, filed as 4454113. robertg@east 2001-06-22
22-06-2001