From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by sourceware.org (Postfix) with ESMTP id 46870385BF83 for ; Tue, 14 Apr 2020 17:54:38 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 46870385BF83 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-469-dbyZL74QPLugpdRFVMd_FQ-1; Tue, 14 Apr 2020 13:54:36 -0400 X-MC-Unique: dbyZL74QPLugpdRFVMd_FQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 89E3F18C35A1 for ; Tue, 14 Apr 2020 17:54:35 +0000 (UTC) Received: from cascais.Home (ovpn04.gateway.prod.ext.ams2.redhat.com [10.39.146.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 032465C1A2 for ; Tue, 14 Apr 2020 17:54:34 +0000 (UTC) From: Pedro Alves To: gdb-patches@sourceware.org Subject: [PATCH 00/28] Decouple inferior_ptid/inferior_thread(); dup ptids in thread list (PR/25412) Date: Tue, 14 Apr 2020 18:54:06 +0100 Message-Id: <20200414175434.8047-1-palves@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-13.4 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_2, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Apr 2020 17:54:40 -0000 In PR/25412, Simon noticed that after the multi-target series, the tid-reuse.exp testcase manages to create a duplicate thread in the thread list. Or rather, two threads with the same PTID. This in turn exposes a design problem in GDB. The inferior_thread() function looks up the current thread based on inferior_ptid: struct thread_info* inferior_thread (void) { struct thread_info *tp =3D find_thread_ptid (current_inferior (), inferi= or_ptid); gdb_assert (tp); return tp; } But if there can be more than one thread in the thread list with the same ptid_t, inferior_thread() may well return the wrong thread. This series fixes this by making the current thread be a global thread_info pointer that is written to directly by switch_to_thread, etc., and making inferior_thread() return that pointer, instead of having inferior_thread() lookup up the inferior_ptid thread, by ptid_t. You can look at this as a continuation of the effort of using more thread_info pointers instead of ptids when possible. This change required auditing the whole codebase for places where we were writing to inferior_ptid directly to change the current thread, and change them to use switch_to_thread instead or one of its siblings, because otherwise inferior_thread() and inferior_ptid would get out of sync and inferior_thread() would return a thread unrelated to the new inferior_ptid we wanted to switch to. That was all (hopefully) done in all the patches leading up to the last one. After this, inferior_ptid still exists, but it is mostly read-only and mainly used by target backend code. It is also relied on by a number of target methods as a global input argument. E.g., the target_resume interface and the memory reading routines -- we still need it there because we need to be able to access memory off of processes for which we don't have a corresponding inferior/thread object, like when handling forks. Maybe we could pass down a context explicitly to target_read_memory, etc. Most of the host-/native-specific code here is untested. I did my best, but I won't be surprised if more tweaking is necessary. Testing on native x86_64 GNU/Linux is regression free for me. Testing against gdbserver has regressed significantly in the past months and is becoming difficult to run with a high number of long timeout sequences; really looks like people aren't paying much attention to that. I think this series doesn't regress gdbserver, but it's getting hard to tell. :-/ Pedro Alves (28): Don't write to inferior_ptid in linux_get_siginfo_data gcore, handle exited threads better Refactor delete_program_space as a destructor Don't write to inferior_ptid in gdbarch-selftests.c, mock address_space too Don't write to inferior_ptid in inf-ptrace.c Don't write to inferior_ptid in target.c Don't write to inferior_ptid in infrun.c Don't write to inferior_ptid in procfs.c Don't write to inferior_ptid in tracefile-tfile.c Don't write to inferior_ptid in tracectf.c Don't write to inferior_ptid in remote.c Don't write to inferior_ptid in remote-sim.c Don't write to inferior_ptid in nto-procfs.c Don't write to inferior_ptid in go32-nat.c Don't write to inferior_ptid in gnu-nat.c Don't write to inferior_ptid in darwin-nat.c Don't write to inferior_ptid in corelow.c Don't write to inferior_ptid in bsd-kvm.c Don't write to inferior_ptid in btrace_fetch Don't write to inferior_ptid in bsd-kvm.c Don't write to inferior_ptid in fork-child.c Don't write to inferior_ptid in go32-nat.c Don't write to inferior_ptid in remote-sim.c Don't write to inferior_ptid in windows-nat.c, part I Don't write to inferior_ptid in windows-nat.c, part II Don't write to inferior_ptid in ravenscar-thread.c Don't write to inferior_ptid in aix-thread.c Decouple inferior_ptid/inferior_thread(); dup ptids in thread list (PR/25412) gdb/aix-thread.c | 2 +- gdb/bsd-kvm.c | 6 +-- gdb/btrace.c | 6 --- gdb/corelow.c | 20 +++++----- gdb/darwin-nat.c | 16 ++++---- gdb/fork-child.c | 3 -- gdb/gdbarch-selftests.c | 17 ++++---- gdb/gdbthread.h | 17 ++++---- gdb/gnu-nat.c | 14 +++---- gdb/go32-nat.c | 8 +--- gdb/inf-ptrace.c | 19 +++++---- gdb/inferior.c | 2 +- gdb/infrun.c | 101 +++++++++++++++++++-------------------------= ---- gdb/linux-tdep.c | 64 ++++++++++++++++-------------- gdb/nat/windows-nat.c | 1 - gdb/nat/windows-nat.h | 3 -- gdb/nto-procfs.c | 24 ++++++------ gdb/procfs.c | 18 ++++----- gdb/progspace.c | 79 ++++++++++++++++++++----------------- gdb/progspace.h | 4 -- gdb/ravenscar-thread.c | 49 ++++++++++++----------- gdb/remote-sim.c | 10 ++--- gdb/remote.c | 34 ++++++++-------- gdb/target.c | 2 +- gdb/thread.c | 97 ++++++++++++++++----------------------------= -- gdb/tracectf.c | 7 ++-- gdb/tracefile-tfile.c | 7 ++-- gdb/windows-nat.c | 68 +++++++++++++++----------------- 28 files changed, 315 insertions(+), 383 deletions(-) base-commit: dd1cab0694592099854e66467319253954c93764 --=20 2.14.5