[Bug go/59433] [4.9 regression] Many 64-bit Go tests SEGV on Solaris

ro at CeBiTec dot Uni-Bielefeld.DE gcc-bugzilla@gcc.gnu.org
Tue Dec 10 13:30:00 GMT 2013


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59433

--- Comment #1 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
I've found what's going on: when I look at the failing bufio test, gdb
prints

gdb) p rfds
Cannot access memory at address 0xfffffd7ffe0f9f00

With pmap, I see the following mappings:

FFFFFD7FFDE00000       2048K rw---    [ anon ]
FFFFFD7FFE101000          4K rw--R    [ stack tid=2 ]
FFFFFD7FFE110000         64K rw---    [ anon ]

I.e. the thread stack starts off with just 4 kB, but rfds is 0x7100
bytes from the top of the stack, way beyond the initial allocation and
thus unmapped.

Each fd_set is 8 kB for 64-bit, so the stack consumption in
netpoll_select.c (runtime_netpoll) is way out of bounds.

As a quick hack, I've increased the initial stack size to StackMin:

diff --git a/libgo/runtime/proc.c b/libgo/runtime/proc.c
--- a/libgo/runtime/proc.c
+++ b/libgo/runtime/proc.c
@@ -185,7 +185,7 @@ runtime_newosproc(M *mp)
     if(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) != 0)
         runtime_throw("pthread_attr_setdetachstate");

-    stacksize = PTHREAD_STACK_MIN;
+    stacksize = StackMin /* PTHREAD_STACK_MIN */;

     // With glibc before version 2.16 the static TLS size is taken
     // out of the stack size, and we get an error or a crash if

which lets all but os/user PASS on i386-pc-solaris2.10 and
sparc-sun-solaris2.11.

    Rainer



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