JDK-8203481 : Incorrect constraint for unextended_sp in frame:safe_for_sender
  • Type: Bug
  • Component: hotspot
  • Sub-Component: runtime
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: linux
  • CPU: generic
  • Submitted: 2018-05-21
  • Updated: 2021-02-01
  • Resolved: 2018-06-24
The Version table provides details related to the release that this issue/RFE will be addressed.

Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.

To download the current JDK release, click here.
JDK 11 JDK 12 Other
11 b20Fixed 12Fixed openjdk8u292Fixed
Related Reports
Relates :  
JDK-8257192 - Integrate AArch64 JIT port into 8u
Relates :  
JDK-8201564 - Make sure that Flight Recorder works on AARCH64 platform
Description
Constraint in safe_for_sender  "unextended sp must be within the stack and above or equal sp" is incorrect.
Comments
-------- Forwarded Message -------- From: Andrew Haley <aph@redhat.com> ... While we're interpreting, the machine SP is always <= the Java expression SP, ESP. When we enter a new intrpreted frame, the old machine SP is saved in interpreter_frame_sender_sp in the new frame and the machine SP is adjusted so that it is just below ESP. interpreter_frame_sender_sp is used to calculate the unextended_sp while we're unwinding the frame. So, A correct frame layout can look like this: 0x000003ffb61bdf40: 0x000003ffb61bdfb0 #2 method java.security.AccessController.getContext()Ljava/security/AccessControlContext; @ 0 - 1 locals 5 max stack 0x000003ffb61bdf38: 0x000003ffb61bdf20 interpreter_frame_sender_sp 0x000003ffb61bdf30: 0x000003ffb61bdef0 interpreter_frame_last_sp 0x000003ffb61bdf28: 0x000003ff88fb0bc0 interpreter_frame_method 0x000003ffb61bdf20: 0x0000000000000000 unextended_sp for #3 interpreter_frame_mdp 0x000003ffb61bdf18: 0x0000000000000000 0x000003ffb61bdf10: 0x000000070ff06a48 interpreter_frame_mirror 0x000003ffb61bdf08: 0x000003ff88fb0de8 interpreter_frame_cache 0x000003ffb61bdf00: 0x000003ffb61bdf50 interpreter_frame_locals 0x000003ffb61bdef8: 0x000003ff88fb0b90 interpreter_frame_bcp 0x000003ffb61bdef0: 0x000003ffb61bdef0 interpreter_frame_initial_sp 0x000003ffb61bdee8: 0x000000070ff06a48 0x000003ffb61bdee0: 0x0000000000000000 sp for #2 0x000003ffb61bded8: 0x000003ffa1081360 0x000003ffb61bded0: 0x000003ffb61bdf40 #1 method java.security.AccessController.getStackAccessControlContext()Ljava/security/AccessControlContext; @ 0 - 0 locals 1 max stack 0x000003ffb61bdec8: 0x000003ffb61bdeb0 interpreter_frame_sender_sp 0x000003ffb61bdec0: 0x0000000000000000 interpreter_frame_last_sp 0x000003ffb61bdeb8: 0x000003ff88fb0a30 interpreter_frame_method 0x000003ffb61bdeb0: 0x0000000000000000 unextended_sp for #2 interpreter_frame_mdp 0x000003ffb61bdea8: 0x0000000000000000 0x000003ffb61bdea0: 0x000000070ff06a48 interpreter_frame_mirror 0x000003ffb61bde98: 0x000003ff88fb0de8 interpreter_frame_cache 0x000003ffb61bde90: 0x000003ffb61bdee8 interpreter_frame_locals 0x000003ffb61bde88: 0x0000000000000000 interpreter_frame_bcp 0x000003ffb61bde80: 0x000003ffb61bde80 sp for #1 interpreter_frame_initial_sp unextended_sp for #1 Note that getStackAccessControlContext()'s saved sender SP from AccessController.getContext() is 0x000003ffb61bdeb0: this really is less than 0x000003ffb61bdee0, which was the SP before getStackAccessControlContext()'s frame was created. This is OK, and explains why the assert failed for you. Given that the unextended_sp can be greater or less than the saved SP, I think the assert can be removed.
10-06-2018
I agree with Dan's comment on review thread. For stacks that grow down the expectation is: sp <= unextended_sp <= stack_base()
22-05-2018
74 // unextended sp must be within the stack and above or equal sp 75 bool unextended_sp_safe = (unextended_sp < thread->stack_base()) && 76 (unextended_sp >= sp); unextended_sp must be *below or equal to sp*. On x86 unextended_sp is always equal to sp so constraint passed, but on aarch64 unextended_sp is below sp.
21-05-2018