From e7af6c702da7a77529afdeffbbe6e13639beb441 Mon Sep 17 00:00:00 2001 From: Tankut Baris Aktemur Date: Fri, 10 Jan 2020 20:05:52 +0000 Subject: [PATCH] Avoid another inferior_ptid reference in gdb/remote.c The multi-target patch makes inferior_ptid point to null_ptid before calling into target_wait, which catches bad uses of inferior_ptid, since the current selected thread in gdb shouldn't have much relation to the thread that reports an event. One such bad use is found in remote_target::remote_parse_stop_reply, where we handle the 'W' or 'X' packets (process exit), and the remote target does not support the multi-process extensions, i.e., it does not report the PID of the process that exited. With the multi-target patch, that would result in a failed assertion, trying to find the inferior for process pid 0. gdb/ChangeLog: 2020-01-10 Tankut Baris Aktemur Pedro Alves * remote.c (remote_target::remote_parse_stop_reply) : If no process is specified, return null_ptid instead of inferior_ptid. (remote_target::wait_as): Handle TARGET_WAITKIND_EXITED / TARGET_WAITKIND_SIGNALLED with no pid. gdb/testsuite/ChangeLog: 2020-01-10 Tankut Baris Aktemur Pedro Alves * gdb.server/connect-without-multi-process.exp: Also test continuing to end. --- gdb/ChangeLog | 9 +++++++++ gdb/remote.c | 18 +++++++++++++----- gdb/testsuite/ChangeLog | 6 ++++++ .../connect-without-multi-process.exp | 7 ++++++- 4 files changed, 34 insertions(+), 6 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 9d63febea0f..78922021681 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,12 @@ +2020-01-10 Tankut Baris Aktemur + Pedro Alves + + * remote.c (remote_target::remote_parse_stop_reply) : + If no process is specified, return null_ptid instead of + inferior_ptid. + (remote_target::wait_as): Handle TARGET_WAITKIND_EXITED / + TARGET_WAITKIND_SIGNALLED with no pid. + 2020-01-10 Pedro Alves * remote.c (first_remote_resumed_thread): New. diff --git a/gdb/remote.c b/gdb/remote.c index fa940dff720..ffdeede7af5 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -7441,7 +7441,6 @@ Packet: '%s'\n"), case 'W': /* Target exited. */ case 'X': { - int pid; ULONGEST value; /* GDB used to accept only 2 hex chars here. Stubs should @@ -7465,8 +7464,9 @@ Packet: '%s'\n"), event->ws.value.sig = GDB_SIGNAL_UNKNOWN; } - /* If no process is specified, assume inferior_ptid. */ - pid = inferior_ptid.pid (); + /* If no process is specified, return null_ptid, and let the + caller figure out the right process to use. */ + int pid = 0; if (*p == '\0') ; else if (*p == ';') @@ -7842,8 +7842,16 @@ remote_target::wait_as (ptid_t ptid, target_waitstatus *status, int options) event_ptid = first_remote_resumed_thread (); } else - /* A process exit. Invalidate our notion of current thread. */ - record_currthread (rs, minus_one_ptid); + { + /* A process exit. Invalidate our notion of current thread. */ + record_currthread (rs, minus_one_ptid); + /* It's possible that the packet did not include a pid. */ + if (event_ptid == null_ptid) + event_ptid = first_remote_resumed_thread (); + /* EVENT_PTID could still be NULL_PTID. Double-check. */ + if (event_ptid == null_ptid) + event_ptid = magic_null_ptid; + } return event_ptid; } diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 4b38c214daf..52d52d15f6c 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2020-01-10 Tankut Baris Aktemur + Pedro Alves + + * gdb.server/connect-without-multi-process.exp: Also test + continuing to end. + 2020-01-10 Pedro Alves * gdb.base/remote-exec-file.exp: New file. diff --git a/gdb/testsuite/gdb.server/connect-without-multi-process.exp b/gdb/testsuite/gdb.server/connect-without-multi-process.exp index 6c7d162492f..123089260dd 100644 --- a/gdb/testsuite/gdb.server/connect-without-multi-process.exp +++ b/gdb/testsuite/gdb.server/connect-without-multi-process.exp @@ -14,7 +14,7 @@ # along with this program. If not, see . */ # Check that we can connect to GDBserver with the multiprocess -# extensions disabled, and run to main. +# extensions disabled, run to main, and finish the process. load_lib gdbserver-support.exp @@ -52,6 +52,11 @@ proc do_test {multiprocess} { "target $gdbserver_protocol" gdb_test "continue" "main .*" "continue to main" + + # The W/X packets do not include the PID of the exiting process + # without the multi-process extensions. Check that we handle + # process exit correctly in that case. + gdb_continue_to_end } foreach multiprocess { "off" "auto" } { -- 2.30.2