Bug 106813

Summary: getSiginfo() libgo/runtime/go-signal.c missing Solaris specific code to get ret.sigpc
Product: gcc Reporter: Petr Sumbera <sumbera>
Component: goAssignee: Ian Lance Taylor <ian>
Status: RESOLVED FIXED    
Severity: normal CC: ebotcazou, marcel, ro
Priority: P3    
Version: 12.2.0   
Target Milestone: ---   
Host: Target: *-solaris
Build: Known to work:
Known to fail: Last reconfirmed: 2024-04-06 00:00:00
Attachments: Proposed patch file.
Alternative patch.

Description Petr Sumbera 2022-09-02 08:44:10 UTC
Created attachment 53531 [details]
Proposed patch file.

getSiginfo() in libgo/runtime/go-signal.c is missing Solaris specific code to get ret.sigpc and thus it calls runtime_callers().

It was observed that sometimes call to runtime_callers() ends with segmentation fault (because sparc64_is_sighandler() gets wrong pc - e.g. 0x8):

ffffffff7ac13fe1 libgcc_s.so.1`uw_frame_state_for+0x434(ffffffff7ac14950,
ffffffff7ac14d40,
ffffffff6ab59e50, ffffffff6ab66a8d, 0, ffffffff6ab66a8d)
ffffffff7ac140a1 libgcc_s.so.1`_Unwind_Backtrace+0x54(ffffffff6a9ce33c,
ffffffff7ac154d0, 0,
ffffffff7ac14d40, ffffffff7ac14950, 0)
ffffffff7ac14c21 libgo.so.14`backtrace_full+0x70(ffffffff7f5c8000, 1,
ffffffff6a4c1790,
ffffffff6a4c1abc, ffffffff7ac155b8, ffffffff6b09d3b8)
ffffffff7ac14d01 libgo.so.14`runtime_callers+0x78(6, ffffffff7ac156a0,
ffffffff7f5c8000, 0,
ffffffff6a4c1abc, ffffffff6b0c7d7c)
ffffffff7ac14dd1 libgo.so.14`runtime.getSiginfo+0x1c(ffffffff7ac15ef0,
ffffffff7ac15c10, 0, 0, 0,
61e000000000)
ffffffff7ac14ed1 libgo.so.14`runtime.sigtrampgo+0x39c(12, ffffffff7ac15ef0,
ffffffff7ac15c10,
ffffffff6ad81b88, 36, c0010c6800)
ffffffff7ac15101 libc.so.1`__sighndlr+0xc(12, ffffffff7ac15ef0,
ffffffff7ac15c10,
ffffffff6a4c2ebc, 0, ffffffff7ed24000)
ffffffff7ac151b1 libc.so.1`call_user_handler+0x404(d, ffffffff7ac15ef0,
ffbffeff, 0, 12, ff)
ffffffff7ac152a1 libc.so.1`sigacthandler+0xe0(12, ffffffff7ac15ef0,
ffffffff7ac15c10, 0, 0,
ffffffff7ed24000)
ffffffff21bff741 libgo.so.14`runtime.kickoff(0, 0, 0, 0, 0, 0)

This can be avoided by setting ret.sigpc via platform specific code as it's done on other systems. See attached patch file.
Comment 1 Rainer Orth 2024-04-02 13:19:16 UTC
FWIW I had a similar patch in my local tree for years, but neglected to submit
it (among others because it lacked dumpregs support.

While going over the remaining go.test failures recently, I noted some that
might be related, so I completed the patch (attached).  A few notes:

* I've used the customary __sun__ && __svr4__ guard for Solaris-specific code,
  not __sun && __SVR4 which is only used in runtime/go-libmain.c.

* I've reused the Linux/x86_64 code in dumpregs for Solaris.  Only a few
  adjustments were necessary, but this still seemed better than replicating
  the whole section.

* I've added SPARC support, too.  Since gregs[] is almost identical between
  32 and 64-bit, I've just used different formats for printing 32 and 64-bit
  registers, again to avoid massive duplication.

* When testing on Debian/sparc64, the 64-bit version there reguired an ugly
  variation: the general-purpose member of mcontext_t is called mc_gregs
  instead of gregs, and the indices are named MC_* instead of REG_* (although
  the names are identical with one exception).  I have no idea what rid them
  to do this, but at least my code does compile and run there.

The patch has been tested on i386-pc-solaris2.11, sparc-sun-solaris2.11,
x86_64-pc-linux-gnu, and sparc64-unknown-linux-gnu (32 and 64-bit each).

There were no regressions, but compared to a vanilla tree there where no new
PASSes either.
Comment 2 Rainer Orth 2024-04-02 13:20:04 UTC
Created attachment 57848 [details]
Alternative patch.
Comment 3 GCC Commits 2024-04-29 18:40:35 UTC
The master branch has been updated by Ian Lance Taylor <ian@gcc.gnu.org>:

https://gcc.gnu.org/g:a05efc8bf5ed329ea7d9b1740c326bdc6b04e37a

commit r15-53-ga05efc8bf5ed329ea7d9b1740c326bdc6b04e37a
Author: Ian Lance Taylor <iant@golang.org>
Date:   Sun Apr 28 13:30:39 2024 -0700

    runtime: dump registers on Solaris
    
    Patch by Rainer Orth <ro@gcc.gnu.org>.
    
    Fixes PR go/106813
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/581724
Comment 4 Ian Lance Taylor 2024-04-29 18:41:48 UTC
Thanks.  Patch committed.  This should be fixed now.