Date: Wed, 23 Aug 2017 16:37:07 +0200 From: Tijl Coosemans <tijl@FreeBSD.org> To: freebsd-current@FreeBSD.org Cc: gerald@FreeBSD.org Subject: Segfault in _Unwind_* code called from pthread_exit Message-ID: <20170823163707.096f93ab@kalimero.tijl.coosemans.org>
next in thread | raw e-mail | index | archive | help
Hi,
The following program segfaults for me on amd64 when linked like this:
cc -o test test.c -lpthread -L/usr/local/lib/gcc5 -lgcc_s -rpath /usr/local/lib/gcc5
--------------------------------
#include <pthread.h>
#include <stdio.h>
void *
thr( void *arg ) {
return( NULL );
}
int
main( void ) {
pthread_t thread;
for( int i = 1; i < 20; i++ ) {
fprintf( stderr, "%d\n", i );
pthread_create( &thread, NULL, thr, NULL );
pthread_join( thread, NULL );
}
return( 0 );
}
--------------------------------
The backtrace looks like this:
Thread 7 received signal SIGSEGV, Segmentation fault.
[Switching to LWP 100511 of process 1886]
uw_frame_state_for (context=context@entry=0x7fffdfffddc0,
fs=fs@entry=0x7fffdfffdb10)
at /usr/ports/lang/gcc5/work/gcc-5.4.0/libgcc/unwind-dw2.c:1249
1249 /usr/ports/lang/gcc5/work/gcc-5.4.0/libgcc/unwind-dw2.c: No such file or directory.
(gdb) bt
#0 uw_frame_state_for (context=context@entry=0x7fffdfffddc0,
fs=fs@entry=0x7fffdfffdb10)
at /usr/ports/lang/gcc5/work/gcc-5.4.0/libgcc/unwind-dw2.c:1249
#1 0x0000000800a66ecb in _Unwind_ForcedUnwind_Phase2 (
exc=exc@entry=0x800658730, context=context@entry=0x7fffdfffddc0)
at /usr/ports/lang/gcc5/work/gcc-5.4.0/libgcc/unwind.inc:155
#2 0x0000000800a67200 in _Unwind_ForcedUnwind (exc=0x800658730,
stop=0x8008428b0 <thread_unwind_stop>, stop_argument=0x0)
at /usr/ports/lang/gcc5/work/gcc-5.4.0/libgcc/unwind.inc:207
#3 0x0000000800842224 in _Unwind_ForcedUnwind (ex=0x800658730,
stop_func=0x8008428b0 <thread_unwind_stop>, stop_arg=0x0)
at /usr/src/lib/libthr/thread/thr_exit.c:106
#4 0x000000080084269f in thread_unwind ()
at /usr/src/lib/libthr/thread/thr_exit.c:172
#5 0x00000008008424d6 in _pthread_exit_mask (status=0x0, mask=0x0)
at /usr/src/lib/libthr/thread/thr_exit.c:254
#6 0x0000000800842359 in _pthread_exit (status=0x0)
at /usr/src/lib/libthr/thread/thr_exit.c:206
#7 0x000000080082ccb1 in thread_start (curthread=0x800658500)
at /usr/src/lib/libthr/thread/thr_create.c:289
#8 0x00007fffdfdfe000 in ?? ()
Backtrace stopped: Cannot access memory at address 0x7fffdfffe000
It happens with gcc6 as well, but not with base libgcc_s.
Can anyone reproduce this? Have there been any changes to stack
unwinding recently (last few months)?
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20170823163707.096f93ab>