Hello community, here is the log from the commit of package gdb for openSUSE:Factory checked in at 2020-02-22 18:56:23 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Comparing /work/SRC/openSUSE:Factory/gdb (Old) and /work/SRC/openSUSE:Factory/.gdb.new.26092 (New) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Package is "gdb" Sat Feb 22 18:56:23 2020 rev:137 rq:777392 version:8.3.1 Changes: -------- --- /work/SRC/openSUSE:Factory/gdb/gdb.changes 2020-01-23 16:10:27.835619836 +0100 +++ /work/SRC/openSUSE:Factory/.gdb.new.26092/gdb.changes 2020-02-22 18:56:28.409178538 +0100 @@ -1,0 +2,6 @@ +Tue Feb 4 19:56:55 UTC 2020 - Tom de Vries <tdevr...@suse.com> + +- Fix hang after SIGKILL [swo#25478]. + * gdb-threads-fix-hang-in-stop_all_threads-after-killing-inferior.patch + +------------------------------------------------------------------- New: ---- gdb-threads-fix-hang-in-stop_all_threads-after-killing-inferior.patch ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Other differences: ------------------ ++++++ gdb.spec ++++++ --- /var/tmp/diff_new_pack.aB3WeV/_old 2020-02-22 18:56:30.573182729 +0100 +++ /var/tmp/diff_new_pack.aB3WeV/_new 2020-02-22 18:56:30.577182737 +0100 @@ -13,7 +13,7 @@ # license that conforms to the Open Source Definition (Version 1.9) # published by the Open Source Initiative. -# Please submit bugfixes or comments via http://bugs.opensuse.org/ +# Please submit bugfixes or comments via https://bugs.opensuse.org/ # @@ -258,6 +258,9 @@ # Proposed patch for PR gdb/24956 Patch2501: gdb-only-force-interp_console-ui_out-for-breakpoint-commands-in-mi-mode.patch +# Proposed patch for PR threads/25478 +Patch2502: gdb-threads-fix-hang-in-stop_all_threads-after-killing-inferior.patch + # Testsuite patches Patch2600: gdb-testsuite-8.3-kfail-xfail-unsupported.patch @@ -610,6 +613,7 @@ %patch2500 -p1 %patch2501 -p1 +%patch2502 -p1 %patch2600 -p1 ++++++ gdb-threads-fix-hang-in-stop_all_threads-after-killing-inferior.patch ++++++ [gdb/threads] Fix hang in stop_all_threads after killing inferior Consider a two-threaded testcase a.out, sleeping in both its threads: ... $ gdb -ex r --args a.out Reading symbols from a.out... Starting program: /data/gdb_versions/devel/a.out [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". [New Thread 0x7ffff77fe700 (LWP 31268)] ... Typing ^C causes stop_all_threads to be executed, and if an external SIGKILL (such as caused by killall -9 a.out) arrives at the start of stop_all_threads, gdb hangs in stop_all_threads after giving this warning: ... warning: unable to open /proc file '/proc/24938/status' ... Using "set debug infrun 1" we can see in more detail where we hang: ... infrun: stop_all_threads infrun: stop_all_threads, pass=0, iterations=0 infrun: Thread 0x7ffff7fa6740 (LWP 10264) not executing infrun: Thread 0x7ffff77fe700 (LWP 10268) executing, need stop infrun: target_wait (-1.0.0, status) = infrun: 10264.10268.0 [Thread 0x7ffff77fe700 (LWP 10268)], infrun: status->kind = signalled, signal = GDB_SIGNAL_KILL infrun: stop_all_threads status->kind = signalled, signal = GDB_SIGNAL_KILL \ Thread 0x7ffff77fe700 (LWP 10268) infrun: Thread 0x7ffff7fa6740 (LWP 10264) not executing infrun: Thread 0x7ffff77fe700 (LWP 10268) executing, already stopping warning: unable to open /proc file '/proc/10264/status' infrun: target_wait (-1.0.0, status) = infrun: -1.0.0 [process -1], infrun: status->kind = no-resumed infrun: infrun_async(0) infrun: stop_all_threads status->kind = no-resumed process -1 infrun: Thread 0x7ffff7fa6740 (LWP 10264) not executing infrun: Thread 0x7ffff77fe700 (LWP 10268) executing, already stopping infrun: stop_all_threads status->kind = no-resumed process -1 infrun: Thread 0x7ffff7fa6740 (LWP 10264) not executing infrun: Thread 0x7ffff77fe700 (LWP 10268) executing, already stopping infrun: stop_all_threads status->kind = no-resumed process -1 infrun: Thread 0x7ffff7fa6740 (LWP 10264) not executing infrun: Thread 0x7ffff77fe700 (LWP 10268) executing, already stopping <repeat> ...... So, we're hanging in the 'while (1)' loop in stop_all_threads as follows: - thread t is tested, and both t->executing and t->stop_requested are found to be 1 (noted with 'executing, already stopping') - consequently need_wait is set 1 - consequently wait_one is executed - wait_one returns a TARGET_WAITKIND_NO_RESUMED event, which is handled by continuing at the start of the loop The loop actually starts with update_thread_list (), but that doesn't seem to change the state of the threads. Fix the hang by: - detecting the first sign of trouble: the TARGET_WAITKIND_SIGNALLED event with signal GDB_SIGNAL_KILL, - making that event pending again, - making sure the corresponding thread will not set need_wait again (by setting t->executing == 0) - making sure that the corresponding thread keeps t->resumed == 1 in the the all_non_exited_threads loop This results in the ^C being handled without showing the user that the test-case was killed: ... ^C Thread 1 received signal SIGINT, Interrupt. 0x00007ffff78c50f0 in nanosleep () from /lib64/libc.so.6 (gdb) ... But a subsequent continue does show that: ... (gdb) c Continuing. Program terminated with signal SIGKILL, Killed. The program no longer exists. (gdb) .... Build and reg-tested on x86_64-linux. gdb/ChangeLog: 2020-01-29 Tom de Vries <tdevr...@suse.de> PR threads/25478 * infrun.c (stop_all_threads): Detecting event TARGET_WAITKIND_SIGNALLED with signal GDB_SIGNAL_KILL, make event pending again, set t->executing to 0 and keep t->resumed set to 1. Change-Id: Ibe1f29251fe2ff1c1991f041babbe18373c113b1 --- gdb/infrun.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/gdb/infrun.c b/gdb/infrun.c index 9d20036fcf..16e9e136c0 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -4344,7 +4344,12 @@ stop_all_threads (void) /* The thread may be not executing, but still be resumed with a pending status to process. */ - t->resumed = 0; + if (t->suspend.waitstatus.kind == TARGET_WAITKIND_SIGNALLED + && t->suspend.waitstatus.value.sig == GDB_SIGNAL_KILL + && t->suspend.waitstatus_pending_p) + ; + else + t->resumed = 0; } } @@ -4359,7 +4364,15 @@ stop_all_threads (void) event_ptid = wait_one (&ws); - if (ws.kind == TARGET_WAITKIND_NO_RESUMED) + if (ws.kind == TARGET_WAITKIND_SIGNALLED + && ws.value.sig == GDB_SIGNAL_KILL) + { + thread_info *t = find_thread_ptid (event_ptid); + save_waitstatus (t, &ws); + t->resumed = 1; + t->executing = 0; + } + else if (ws.kind == TARGET_WAITKIND_NO_RESUMED) { /* All resumed threads exited. */ }
