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From: "ppluzhnikov at google dot com" <sourceware-bugzilla@sourceware.org> To: gdb-prs@sourceware.org Subject: [Bug threads/10227] New: GDB resumes inferior unexpectedly when receiving ignored signal; step/next behave as continue Date: Tue, 02 Jun 2009 06:15:00 -0000 [thread overview] Message-ID: <20090602061531.10227.ppluzhnikov@google.com> (raw) Reproduces in 32 and 64-bit mode using CVS Head. The test case below generates endless stream of SIGPIPEs, which are SIG_IGNored. When "handle SIGPIPE nostop noprint pass" is in effect, everything works as expected. But when "handle SIGPIPE nostop print pass", then executing "next" turns into "continue" instead, as can be seen in this log: $ gdb64-cvs ./a.out GNU gdb (GDB) 6.8.50.20090601-cvs ... This GDB was configured as "x86_64-unknown-linux-gnu". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>... (gdb) b foo Breakpoint 1 at 0x40070d: file sigpipe.c, line 22. (gdb) handle SIGPIPE nostop print pass (gdb) run [Thread debugging using libthread_db enabled] [New Thread 0x40800950 (LWP 29291)] Breakpoint 1, foo () at sigpipe.c:22 22 return 42; (gdb) finish 0x00000000004007a7 in main () at sigpipe.c:53 53 int x = foo(); Value returned is $1 = 42 (gdb) next 54 bar(x); (gdb) next Program received signal SIGPIPE, Broken pipe. Breakpoint 1, foo () at sigpipe.c:22 <<< How did we end up inside foo() ??? 22 return 42; <<< We should have stopped on line 53. --- cut --- /* compile with "gcc -pthread -g t.c" * Test program generates an endless stream of SIGPIPE in second thread. */ #include <stdlib.h> #include <unistd.h> #include <signal.h> #include <pthread.h> void *fn(void *p) { int fd = *(int*)p; while (1) { int x = 1; x++; x++; write(fd, &x, sizeof(x)); } } int foo() { return 42; } int bar(int x) { return x - 1; } int main() { int fd[2]; pthread_t tid; signal(SIGPIPE, SIG_IGN); if (pipe(fd) == -1) return 1; switch (fork()) { case 0: /* child */ exit(0); case -1: return 1; default: /* parent */ close(fd[0]); pthread_create(&tid, 0, fn, &fd[1]); } while (1) { int x = foo(); bar(x); } return 0; } --- cut --- -- Summary: GDB resumes inferior unexpectedly when receiving ignored signal; step/next behave as continue Product: gdb Version: 6.8 Status: UNCONFIRMED Severity: normal Priority: P3 Component: threads AssignedTo: unassigned at sourceware dot org ReportedBy: ppluzhnikov at google dot com CC: gdb-prs at sourceware dot org GCC build triplet: x86_64-unknown-linux-gnu GCC host triplet: x86_64-unknown-linux-gnu GCC target triplet: x86_64-unknown-linux-gnu http://sourceware.org/bugzilla/show_bug.cgi?id=10227 ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is.
next reply other threads:[~2009-06-02 6:15 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-06-02 6:15 ppluzhnikov at google dot com [this message] 2009-06-02 6:36 ` [Bug threads/10227] " ppluzhnikov at google dot com
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