| Message ID | 510f2362-8d33-4c3c-9a13-5d187f26abdf@SVR-ORW-FEM-04.mgc.mentorg.com |
|---|---|
| State | New |
| Headers | show |
Hi Pedro, This issue is introduced by the patches for PR 12702 that was pushed by you. Maybe you could take a look on this patch. Thanks, Hui On 06/23/14 18:09, Hui Zhu wrote: > gdbserver :1234 gdb.base/watch_thread_num > gdb gdb.base/watch_thread_num > (gdb) b 48 > Breakpoint 1 at 0x400737: file ../../../binutils-gdb/gdb/testsuite/gdb.base/watch_thread_num.c, line 48. > (gdb) c > Continuing. > > Breakpoint 1, main () at ../../../binutils-gdb/gdb/testsuite/gdb.base/watch_thread_num.c:48 > 48 thread_result = thread_function ((void *) i); > (gdb) k > Kill the program being debugged? (y or n) y > gdbserver :1234 gdb.base/watch_thread_num > Process gdb.base/watch_thread_num created; pid = 9719 > Listening on port 1234 > Remote debugging from host 127.0.0.1 > Killing all inferiors > Segmentation fault (core dumped) > > Backtrace: > (gdb) bt > #0 find_inferior (list=<optimized out>, func=func@entry=0x423990 <kill_one_lwp_callback>, arg=arg@entry=0x7fffe97405dc) > at ../../../binutils-gdb/gdb/gdbserver/inferiors.c:199 > #1 0x0000000000425bff in linux_kill (pid=10130) at ../../../binutils-gdb/gdb/gdbserver/linux-low.c:966 > #2 0x000000000040ae8c in kill_inferior_callback (entry=<optimized out>) at ../../../binutils-gdb/gdb/gdbserver/server.c:2934 > #3 0x0000000000405c61 in for_each_inferior (list=<optimized out>, action=action@entry=0x40ae60 <kill_inferior_callback>) > at ../../../binutils-gdb/gdb/gdbserver/inferiors.c:57 > #4 0x000000000040d5e2 in process_serial_event () at ../../../binutils-gdb/gdb/gdbserver/server.c:3767 > #5 handle_serial_event (err=<optimized out>, client_data=<optimized out>) at ../../../binutils-gdb/gdb/gdbserver/server.c:3880 > #6 0x0000000000412cda in handle_file_event (event_file_desc=event_file_desc@entry=4) > at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:434 > #7 0x000000000041357a in process_event () at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:189 > #8 start_event_loop () at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:552 > #9 0x0000000000403088 in main (argc=3, argv=0x7fffe9740938) at ../../../binutils-gdb/gdb/gdbserver/server.c:3283 > > The cause of this issue is when linux_kill call "find_inferior (&all_threads, kill_one_lwp_callback , &pid)" > to kill all the lwp of pid. > In linux_wait_for_event, it will delete_lwp any lwp in all_threads if it > get exit event of it. Then it make find_inferior crash. > > I make a patch that let kill_one_lwp_callback return 1, then after > linux_wait_for_event is called(Maybe all_threads is changed), find_inferior > will return. > And change call "find_inferior (&all_threads, kill_one_lwp_callback , &pid)" > to be a loop. It will stop when all_threads doesn't have any lwp is pid. > > It pass regression test in x86_64 Linux. > > Thanks, > Hui > > 2014-06-23 Hui Zhu <hui@codesourcery.com> > > * linux-low.c (kill_one_lwp_callback): Change last return to 1. > (linux_kill): Call find_inferior with a loop. > > --- a/gdb/gdbserver/linux-low.c > +++ b/gdb/gdbserver/linux-low.c > @@ -944,7 +944,9 @@ kill_one_lwp_callback (struct inferior_l > pid = linux_wait_for_event (thread->entry.id, &wstat, __WALL); > } while (pid > 0 && WIFSTOPPED (wstat)); > > - return 0; > + /* Let find_inferior return because maybe other lwp in the list will > + be deleted by delete_lwp. */ > + return 1; > } > > static int > @@ -963,7 +965,9 @@ linux_kill (int pid) > first, as PTRACE_KILL will not work otherwise. */ > stop_all_lwps (0, NULL); > > - find_inferior (&all_threads, kill_one_lwp_callback , &pid); > + /* Keep call kill_one_lwp_callback until find_inferior cannot find any > + lwps that is for pid. */ > + while (find_inferior (&all_threads, kill_one_lwp_callback , &pid) != NULL); > > /* See the comment in linux_kill_one_lwp. We did not kill the first > thread in the list, so do so now. */ >
On 06/29/2014 04:28 AM, Hui Zhu wrote: > Hi Pedro, > > This issue is introduced by the patches for PR 12702 that was pushed by you. > Maybe you could take a look on this patch. Thanks. I'll need to think a bit about whether this is the right solution. I've added it to the 7.8 regression queue at: https://sourceware.org/gdb/wiki/GDB_7.8_Release I'll look better at it as soon as I have a chance.
--- a/gdb/gdbserver/linux-low.c +++ b/gdb/gdbserver/linux-low.c @@ -944,7 +944,9 @@ kill_one_lwp_callback (struct inferior_l pid = linux_wait_for_event (thread->entry.id, &wstat, __WALL); } while (pid > 0 && WIFSTOPPED (wstat)); - return 0; + /* Let find_inferior return because maybe other lwp in the list will + be deleted by delete_lwp. */ + return 1; } static int @@ -963,7 +965,9 @@ linux_kill (int pid) first, as PTRACE_KILL will not work otherwise. */ stop_all_lwps (0, NULL); - find_inferior (&all_threads, kill_one_lwp_callback , &pid); + /* Keep call kill_one_lwp_callback until find_inferior cannot find any + lwps that is for pid. */ + while (find_inferior (&all_threads, kill_one_lwp_callback , &pid) != NULL); /* See the comment in linux_kill_one_lwp. We did not kill the first thread in the list, so do so now. */
gdbserver :1234 gdb.base/watch_thread_num gdb gdb.base/watch_thread_num (gdb) b 48 Breakpoint 1 at 0x400737: file ../../../binutils-gdb/gdb/testsuite/gdb.base/watch_thread_num.c, line 48. (gdb) c Continuing. Breakpoint 1, main () at ../../../binutils-gdb/gdb/testsuite/gdb.base/watch_thread_num.c:48 48 thread_result = thread_function ((void *) i); (gdb) k Kill the program being debugged? (y or n) y gdbserver :1234 gdb.base/watch_thread_num Process gdb.base/watch_thread_num created; pid = 9719 Listening on port 1234 Remote debugging from host 127.0.0.1 Killing all inferiors Segmentation fault (core dumped) Backtrace: (gdb) bt #0 find_inferior (list=<optimized out>, func=func@entry=0x423990 <kill_one_lwp_callback>, arg=arg@entry=0x7fffe97405dc) at ../../../binutils-gdb/gdb/gdbserver/inferiors.c:199 #1 0x0000000000425bff in linux_kill (pid=10130) at ../../../binutils-gdb/gdb/gdbserver/linux-low.c:966 #2 0x000000000040ae8c in kill_inferior_callback (entry=<optimized out>) at ../../../binutils-gdb/gdb/gdbserver/server.c:2934 #3 0x0000000000405c61 in for_each_inferior (list=<optimized out>, action=action@entry=0x40ae60 <kill_inferior_callback>) at ../../../binutils-gdb/gdb/gdbserver/inferiors.c:57 #4 0x000000000040d5e2 in process_serial_event () at ../../../binutils-gdb/gdb/gdbserver/server.c:3767 #5 handle_serial_event (err=<optimized out>, client_data=<optimized out>) at ../../../binutils-gdb/gdb/gdbserver/server.c:3880 #6 0x0000000000412cda in handle_file_event (event_file_desc=event_file_desc@entry=4) at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:434 #7 0x000000000041357a in process_event () at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:189 #8 start_event_loop () at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:552 #9 0x0000000000403088 in main (argc=3, argv=0x7fffe9740938) at ../../../binutils-gdb/gdb/gdbserver/server.c:3283 The cause of this issue is when linux_kill call "find_inferior (&all_threads, kill_one_lwp_callback , &pid)" to kill all the lwp of pid. In linux_wait_for_event, it will delete_lwp any lwp in all_threads if it get exit event of it. Then it make find_inferior crash. I make a patch that let kill_one_lwp_callback return 1, then after linux_wait_for_event is called(Maybe all_threads is changed), find_inferior will return. And change call "find_inferior (&all_threads, kill_one_lwp_callback , &pid)" to be a loop. It will stop when all_threads doesn't have any lwp is pid. It pass regression test in x86_64 Linux. Thanks, Hui 2014-06-23 Hui Zhu <hui@codesourcery.com> * linux-low.c (kill_one_lwp_callback): Change last return to 1. (linux_kill): Call find_inferior with a loop.