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fix gdbserver/linux-low'c's pending status handling

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Another fix I'm working made schedlock.exp fail with gdbserver
frequently.  Looking deeper, it turns out to be a pre-existing bug.

status_pending_p_callback is filtering out LWPs incorrectly.  The
result is that that sometimes status_pending_p_callback returns a
pending event for an LWP that isn't expected, and then GDBserver gets
very confused.

E.g,. when doing a step-over, linux_wait_for_event is called with a
particular LWP's ptid, meaning events for all other LWPs should be
left pending, but here we see it retuning an event for some other LWP:

 linux_wait_1: [<all threads>]
 step_over_bkpt set [LWP 29577.29577], doing a blocking wait      <--------
 my_waitpid (-1, 0x40000001)
 my_waitpid (-1, 0x80000001): status(57f), 0
 LWFE: waitpid(-1, ...) returned 0, ERRNO-OK
 pc is 0x4007a0
 src/gdb/gdbserver/linux-low.c:2587: A problem internal to GDBserver has been detected.
 linux_wait_1: got event for 29581                                <--------

 Remote connection closed
 (gdb) FAIL: gdb.threads/schedlock.exp: continue to breakpoint: return to loop (initial)
 delete breakpoints

Tested on x86_64 Fedora 20.

gdb/gdbserver/ChangeLog:
2015-02-20  Pedro Alves  <palves@redhat.com>

	* linux-low.c (status_pending_p_callback): Use ptid_match.
This commit is contained in:
Pedro Alves 2015-02-19 20:48:54 +00:00
parent 60fb7e9efa
commit afa8d396f6
2 changed files with 6 additions and 3 deletions
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4
gdb/gdbserver/ChangeLog
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@ -1,3 +1,7 @@
2015-02-20 Pedro Alves <palves@redhat.com>
* linux-low.c (status_pending_p_callback): Use ptid_match.
2015-02-19 Antoine Tremblay <antoine.tremblay@ericsson.com>
PR breakpoints/16812

5
gdb/gdbserver/linux-low.c
View File

@ -1288,9 +1288,8 @@ status_pending_p_callback (struct inferior_list_entry *entry, void *arg)
ptid_t ptid = * (ptid_t *) arg;
/* Check if we're only interested in events from a specific process
or its lwps. */
if (!ptid_equal (minus_one_ptid, ptid)
&& ptid_get_pid (ptid) != ptid_get_pid (thread->entry.id))
or a specific LWP. */
if (!ptid_match (ptid_of (thread), ptid))
return 0;
if (lp->status_pending_p