https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90059
Bug ID: 90059
Summary: Solaris mcontext_t, ucontext_t declarations are wrong
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: d
Assignee: ibuclaw at gdcproject dot org
Reporter: ro at gcc dot gnu.org
Target Milestone: ---
Target: *-*-solaris2.*
Initially, all Solaris 11/SPARC execution tests (both 32 and 64-bit) FAILed
like
this:
Thread 2 received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1 (LWP 1)]
0xfec37d08 in rw_wrlock_impl () from /lib/libc.so.1
(gdb) where
#0 0xfec37d08 in rw_wrlock_impl () from /lib/libc.so.1
#1 0xfec3e62c in sigaction () from /lib/libc.so.1
#2 0x000a8be4 in runModuleUnitTests ()
at /vol/gcc/src/hg/trunk/solaris/libphobos/libdruntime/core/runtime.d:506
#3 0x0007bfac in runAll (this=this@entry=0xffbfe78c)
at /vol/gcc/src/hg/trunk/solaris/libphobos/libdruntime/rt/dmain2.d:484
#4 0x0007ba9c in tryExec (this=0xffbfe78c, dg=...)
at /vol/gcc/src/hg/trunk/solaris/libphobos/libdruntime/rt/dmain2.d:460
#5 0x0007bcb4 in _d_run_main (argc=1, argv=<optimized out>,
mainFunc=<optimized out>)
at /vol/gcc/src/hg/trunk/solaris/libphobos/libdruntime/rt/dmain2.d:493
#6 0x000686d4 in main (argc=1, argv=0xffbfe864)
at /vol/gcc/src/hg/trunk/solaris/libphobos/libdruntime/__entrypoint.di:44
#7 0x000684c4 in _start ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
with libphobos built with -g3 -O0:
0xfec37cec <rw_wrlock_impl>: save %sp, -96, %sp
0xfec37cf0 <rw_wrlock_impl+4>: ld [ %g7 + 0x54 ], %i5
0xfec37cf4 <rw_wrlock_impl+8>: sethi %hi(0x2800), %i3
0xfec37cf8 <rw_wrlock_impl+12>: mov %g7, %l6
0xfec37cfc <rw_wrlock_impl+16>: add %i3, 0x146, %i2
0xfec37d00 <rw_wrlock_impl+20>: rd %pc, %i4
0xfec37d04 <rw_wrlock_impl+24>: sethi %hi(0x6a000), %g1
=> 0xfec37d08 <rw_wrlock_impl+28>: ldsb [ %i5 + %i2 ], %l7
(gdb) p/x $i5
$14 = 0x0
(gdb) p/x $i2
$15 = 0x2946
The first arg (an rwlock_t *) should never be NULL.
After some debugging, this turned out to be memory corruption happening after
the call to swapcontext in fiber_switchContext. The root cause was that the
declarations
of mcontext_t and ucontext_t in core.sys.posix.ucontext are badly wrong for
Solaris/SPARC. After correcting them as in the attached patch, those SEGVs
are gone.
Solaris/x86 is mostly right, the only correction being the introduction of the
uc_xrs member of struct ucontext_t. This doesn't change either size or
alignment, so it's primarily a cosmetic issue.
This again seems strongly to argue for an approach like libgo's (generating
Go structure declarations from the system headers at build time) or at least
libsanitizer's (verifying struct sizes and member offsets at runtime) to avoid
such isses.
