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[pushed] fix gdbserver/linux-low'c's pending status handling
- From: Pedro Alves <palves at redhat dot com>
- To: GDB Patches <gdb-patches at sourceware dot org>
- Date: Tue, 24 Feb 2015 12:37:27 +0000
- Subject: [pushed] fix gdbserver/linux-low'c's pending status handling
- Authentication-results: sourceware.org; auth=none
Seems like this mail never made it to the list for some reason.
Here it is, a bit belatedly...
---
From: Pedro Alves <palves@redhat.com>
Date: Thu, 19 Feb 2015 20:48:54 +0000
Subject: [PATCH] fix gdbserver/linux-low'c's pending status handling
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.
---
gdb/gdbserver/ChangeLog | 4 ++++
gdb/gdbserver/linux-low.c | 5 ++---
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 06848e0..cd79d75 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -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
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 1869857..a6e1e3d 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -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
--
1.9.3