From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randolph Chung Subject: [parisc-linux] Multiple signals? Date: Fri, 5 Nov 2004 10:28:40 -0800 Message-ID: <20041105182840.GA7666@tausq.org> Reply-To: Randolph Chung Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="5mCyUwZo2JvN/JJP" To: parisc-linux@lists.parisc-linux.org Return-Path: List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org --5mCyUwZo2JvN/JJP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Found a problem while debugging gdb.. it looks like we don't correctly handle multiple pending signals in the kernel? For example, if a task has both a SIGTRAP and a SIGALRM pending, it looks like we only deliver the SIGTRAP but not the SIGALRM. Argh... Does anybody have an ideas how to debug/fix this? i thought it's just a matter of making intr_do_signal and syscall_do_signal loop back to recheck the SIGPENDING flags, but that doesn't seem to do it.... Test case: compile the attached program with gcc -g -o sigstep sigstep.c then do something like: (gdb) b handler Breakpoint 1 at 0x10608: file /home/tausq/gdb/gdb-cvs/gdb/testsuite/gdb.base/sigstep.c, line 31. (gdb) b 66 Breakpoint 2 at 0x106f4: file /home/tausq/gdb/gdb-cvs/gdb/testsuite/gdb.base/sigstep.c, line 66. (gdb) run Starting program: /home/tausq/gdb/build-cvs/gdb/testsuite/gdb.base/sigstep Breakpoint 2, main () at /home/tausq/gdb/gdb-cvs/gdb/testsuite/gdb.base/sigstep.c:66 66 while (!done); (gdb) step Breakpoint 2, main () at /home/tausq/gdb/gdb-cvs/gdb/testsuite/gdb.base/sigstep.c:66 66 while (!done); notice that the printf in the signal handler never gets triggered, and we never stop at the breakpoint on the signal handler.... i wonder if this might also explain some other "lost signals" problems others are seeing? randolph -- Randolph Chung Debian GNU/Linux Developer, hppa/ia64 ports http://www.tausq.org/ --5mCyUwZo2JvN/JJP Content-Type: text/x-csrc; charset=us-ascii Content-Disposition: attachment; filename="sigstep.c" /* This testcase is part of GDB, the GNU debugger. Copyright 2004 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include #include #include #include static volatile int done; static void handler (int sig) { printf("in handler\n"); done = 1; } /* handler */ struct itimerval itime; struct sigaction action; /* The enum is so that GDB can easily see these macro values. */ enum { itimer_real = ITIMER_REAL, itimer_virtual = ITIMER_VIRTUAL } itimer = ITIMER_VIRTUAL; main () { /* Set up the signal handler. */ memset (&action, 0, sizeof (action)); action.sa_handler = handler; sigaction (SIGVTALRM, &action, NULL); sigaction (SIGALRM, &action, NULL); /* The values needed for the itimer. This needs to be at least long enough for the setitimer() call to return. */ memset (&itime, 0, sizeof (itime)); itime.it_value.tv_usec = 250 * 1000; /* Loop for ever, constantly taking an interrupt. */ while (1) { /* Set up a one-off timer. A timer, rather than SIGSEGV, is used as after a timer handler finishes the interrupted code can safely resume. */ setitimer (itimer, &itime, NULL); /* Wait. */ while (!done); done = 0; } } --5mCyUwZo2JvN/JJP Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux --5mCyUwZo2JvN/JJP--