From 089436f78743628b22e87c2f8d32bd5f9d818f5a Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Fri, 12 Feb 2021 20:12:37 +0100 Subject: [PATCH] [gdb/threads] Fix lin_thread_get_thread_signals for glibc 2.28 When running test-case gdb.threads/create-fail.exp on openSUSE Factory (with glibc version 2.32) I run into: ... (gdb) continue Continuing. [New Thread 0x7ffff7c83700 (LWP 626354)] [New Thread 0x7ffff7482700 (LWP 626355)] [Thread 0x7ffff7c83700 (LWP 626354) exited] [New Thread 0x7ffff6c81700 (LWP 626356)] [Thread 0x7ffff7482700 (LWP 626355) exited] [New Thread 0x7ffff6480700 (LWP 626357)] [Thread 0x7ffff6c81700 (LWP 626356) exited] [New Thread 0x7ffff5c7f700 (LWP 626358)] [Thread 0x7ffff6480700 (LWP 626357) exited] pthread_create: 22: Invalid argument Thread 6 "create-fail" received signal SIG32, Real-time event 32. [Switching to Thread 0x7ffff5c7f700 (LWP 626358)] 0x00007ffff7d87695 in clone () from /lib64/libc.so.6 (gdb) FAIL: gdb.threads/create-fail.exp: iteration 1: run till end ... The problem is that glibc-internal signal SIGCANCEL is not recognized by gdb. There's code in check_thread_signals that is supposed to take care of that, but it's not working because this code in lin_thread_get_thread_signals has stopped working: ... /* NPTL reserves the first two RT signals, but does not provide any way for the debugger to query the signal numbers - fortunately they don't change. */ sigaddset (set, __SIGRTMIN); sigaddset (set, __SIGRTMIN + 1); ... Since glibc commit d2dc5467c6 "Filter out NPTL internal signals (BZ #22391)" (first released as part of glibc 2.28), a sigaddset with a glibc-internal signal has no other effect than setting errno to EINVALID. Fix this by eliminating the usage of sigset_t in check_thread_signals and lin_thread_get_thread_signals. The same problem was observed on Ubuntu 20.04. Tested on x86_64-linux, openSUSE Factory. Tested on aarch64-linux, Ubuntu 20.04 and Ubuntu 18.04. gdb/ChangeLog: 2021-02-12 Tom de Vries PR threads/26228 * linux-nat.c (lin_thread_get_thread_signals): Remove. (lin_thread_signals): New static var. (lin_thread_get_thread_signal_num, lin_thread_get_thread_signal): New function. * linux-nat.h (lin_thread_get_thread_signals): Remove. (lin_thread_get_thread_signal_num, lin_thread_get_thread_signal): Declare. * linux-thread-db.c (check_thread_signals): Use lin_thread_get_thread_signal_num and lin_thread_get_thread_signal. --- gdb/ChangeLog | 13 +++++++++++++ gdb/linux-nat.c | 26 +++++++++++++++++--------- gdb/linux-nat.h | 7 +++++-- gdb/linux-thread-db.c | 21 +++++---------------- 4 files changed, 40 insertions(+), 27 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index c71d779ced8..e79b9535f70 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,16 @@ +2021-02-12 Tom de Vries + + PR threads/26228 + * linux-nat.c (lin_thread_get_thread_signals): Remove. + (lin_thread_signals): New static var. + (lin_thread_get_thread_signal_num, lin_thread_get_thread_signal): + New function. + * linux-nat.h (lin_thread_get_thread_signals): Remove. + (lin_thread_get_thread_signal_num, lin_thread_get_thread_signal): + Declare. + * linux-thread-db.c (check_thread_signals): Use + lin_thread_get_thread_signal_num and lin_thread_get_thread_signal. + 2021-02-12 Andrew Burgess * f-exp.y (f77_keywords): Add allocated. diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c index 10419dc7bb5..42dcd77ac45 100644 --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -4411,16 +4411,24 @@ Enables printf debugging output."), the GNU/Linux Threads library and therefore doesn't really belong here. */ -/* Return the set of signals used by the threads library in *SET. */ +/* NPTL reserves the first two RT signals, but does not provide any + way for the debugger to query the signal numbers - fortunately + they don't change. */ +static int lin_thread_signals[] = { __SIGRTMIN, __SIGRTMIN + 1 }; -void -lin_thread_get_thread_signals (sigset_t *set) +/* See linux-nat.h. */ + +unsigned int +lin_thread_get_thread_signal_num (void) { - sigemptyset (set); + return sizeof (lin_thread_signals) / sizeof (lin_thread_signals[0]); +} - /* NPTL reserves the first two RT signals, but does not provide any - way for the debugger to query the signal numbers - fortunately - they don't change. */ - sigaddset (set, __SIGRTMIN); - sigaddset (set, __SIGRTMIN + 1); +/* See linux-nat.h. */ + +int +lin_thread_get_thread_signal (unsigned int i) +{ + gdb_assert (i < lin_thread_get_thread_signal_num ()); + return lin_thread_signals[i]; } diff --git a/gdb/linux-nat.h b/gdb/linux-nat.h index a5547f282ad..ff4d753422d 100644 --- a/gdb/linux-nat.h +++ b/gdb/linux-nat.h @@ -304,8 +304,11 @@ void check_for_thread_db (void); true on success, false if the process isn't using libpthread. */ extern int thread_db_notice_clone (ptid_t parent, ptid_t child); -/* Return the set of signals used by the threads library. */ -extern void lin_thread_get_thread_signals (sigset_t *mask); +/* Return the number of signals used by the threads library. */ +extern unsigned int lin_thread_get_thread_signal_num (void); + +/* Return the i-th signal used by the threads library. */ +extern int lin_thread_get_thread_signal (unsigned int i); /* Find process PID's pending signal set from /proc/pid/status. */ void linux_proc_pending_signals (int pid, sigset_t *pending, diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c index dce4bd23c1b..4dab64ac344 100644 --- a/gdb/linux-thread-db.c +++ b/gdb/linux-thread-db.c @@ -161,8 +161,6 @@ static thread_db_target the_thread_db_target; /* Non-zero if we have determined the signals used by the threads library. */ static int thread_signals; -static sigset_t thread_stop_set; -static sigset_t thread_print_set; struct thread_db_info { @@ -1225,23 +1223,14 @@ check_thread_signals (void) { if (!thread_signals) { - sigset_t mask; int i; - lin_thread_get_thread_signals (&mask); - sigemptyset (&thread_stop_set); - sigemptyset (&thread_print_set); - - for (i = 1; i < NSIG; i++) + for (i = 0; i < lin_thread_get_thread_signal_num (); i++) { - if (sigismember (&mask, i)) - { - if (signal_stop_update (gdb_signal_from_host (i), 0)) - sigaddset (&thread_stop_set, i); - if (signal_print_update (gdb_signal_from_host (i), 0)) - sigaddset (&thread_print_set, i); - thread_signals = 1; - } + int sig = lin_thread_get_thread_signal (i); + signal_stop_update (gdb_signal_from_host (sig), 0); + signal_print_update (gdb_signal_from_host (sig), 0); + thread_signals = 1; } } } -- 2.30.2