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authorSimon Marchi <simon.marchi@efficios.com>2020-08-07 10:59:33 -0400
committerSimon Marchi <simon.marchi@polymtl.ca>2020-08-07 10:59:35 -0400
commitb161a60d1fe2a7383c7940815687c6100b97204e (patch)
treef12e3423a7fe7902cd700b3594e3de8ebe09bf15 /gdb/observable.h
parentd2854d8d5a82946ace7f5b626f19c2b73f86d1f6 (diff)
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gdb: pass target to thread_ptid_changed observable
I noticed what I think is a potential bug. I did not observe it nor was I able to reproduce it using actual debugging. It's quite unlikely, because it involves multi-target and ptid clashes. I added selftests that demonstrate it though. The thread_ptid_changed observer says that thread with OLD_PTID now has NEW_PTID. Now, if for some reason we happen to have two targets defining a thread with OLD_PTID, the observers don't know which thread this is about. regcache::regcache_thread_ptid_changed changes all regcaches with OLD_PTID. If there is a regcache for a thread with ptid OLD_PTID, but that belongs to a different target, this regcache will be erroneously changed. Similarly, infrun_thread_ptid_changed updates inferior_ptid if inferior_ptid matches OLD_PTID. But if inferior_ptid currently refers not to the thread is being changed, but to a thread with the same ptid belonging to a different target, then inferior_ptid will erroneously be changed. This patch adds a `process_stratum_target *` parameter to the `thread_ptid_changed` observable and makes the two observers use it. Tests for both are added, which would fail if the corresponding fix wasn't done. gdb/ChangeLog: * observable.h (thread_ptid_changed): Add parameter `process_stratum_target *`. * infrun.c (infrun_thread_ptid_changed): Add parameter `process_stratum_target *` and use it. (selftests): New namespace. (infrun_thread_ptid_changed): New function. (_initialize_infrun): Register selftest. * regcache.c (regcache_thread_ptid_changed): Add parameter `process_stratum_target *` and use it. (regcache_thread_ptid_changed): New function. (_initialize_regcache): Register selftest. * thread.c (thread_change_ptid): Pass target to thread_ptid_changed observable. Change-Id: I0599e61224b6d154a7b55088a894cb88298c3c71
Diffstat (limited to 'gdb/observable.h')
-rw-r--r--gdb/observable.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/gdb/observable.h b/gdb/observable.h
index 070cf0f..da0a9b1 100644
--- a/gdb/observable.h
+++ b/gdb/observable.h
@@ -27,6 +27,7 @@ struct so_list;
struct objfile;
struct thread_info;
struct inferior;
+struct process_stratum_target;
struct trace_state_variable;
namespace gdb
@@ -165,8 +166,9 @@ extern observable<struct gdbarch */* newarch */> architecture_changed;
/* The thread's ptid has changed. The OLD_PTID parameter specifies
the old value, and NEW_PTID specifies the new value. */
-extern observable<ptid_t /* old_ptid */, ptid_t /* new_ptid */>
- thread_ptid_changed;
+extern observable<process_stratum_target * /* target */,
+ ptid_t /* old_ptid */, ptid_t /* new_ptid */>
+ thread_ptid_changed;
/* The inferior INF has been added to the list of inferiors. At
this point, it might not be associated with any process. */