old-cross-binutils/gdb/testsuite/gdb.threads/tid-reuse.c

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Crash on thread id wrap around On GNU/Linux, if the target reuses the TID of a thread that GDB still has in its list marked as THREAD_EXITED, GDB crashes, like: (gdb) continue Continuing. src/gdb/thread.c:789: internal-error: set_running: Assertion `tp->state != THREAD_EXITED' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) FAIL: gdb.threads/tid-reuse.exp: continue to breakpoint: after_reuse_time (GDB internal error) Here: (top-gdb) bt #0 internal_error (file=0x953dd8 "src/gdb/thread.c", line=789, fmt=0x953da0 "%s: Assertion `%s' failed.") at src/gdb/common/errors.c:54 #1 0x0000000000638514 in set_running (ptid=..., running=1) at src/gdb/thread.c:789 #2 0x00000000004bda42 in linux_handle_extended_wait (lp=0x16f5760, status=0, stopping=0) at src/gdb/linux-nat.c:2114 #3 0x00000000004bfa24 in linux_nat_filter_event (lwpid=20570, status=198015) at src/gdb/linux-nat.c:3127 #4 0x00000000004c070e in linux_nat_wait_1 (ops=0xe193d0, ptid=..., ourstatus=0x7fffffffd2c0, target_options=1) at src/gdb/linux-nat.c:3478 #5 0x00000000004c1015 in linux_nat_wait (ops=0xe193d0, ptid=..., ourstatus=0x7fffffffd2c0, target_options=1) at src/gdb/linux-nat.c:3722 #6 0x00000000004c92d2 in thread_db_wait (ops=0xd80b60 <thread_db_ops>, ptid=..., ourstatus=0x7fffffffd2c0, options=1) at src/gdb/linux-thread-db.c:1525 #7 0x000000000066db43 in delegate_wait (self=0xd80b60 <thread_db_ops>, arg1=..., arg2=0x7fffffffd2c0, arg3=1) at src/gdb/target-delegates.c:116 #8 0x000000000067e54b in target_wait (ptid=..., status=0x7fffffffd2c0, options=1) at src/gdb/target.c:2206 #9 0x0000000000625111 in fetch_inferior_event (client_data=0x0) at src/gdb/infrun.c:3275 #10 0x0000000000648a3b in inferior_event_handler (event_type=INF_REG_EVENT, client_data=0x0) at src/gdb/inf-loop.c:56 #11 0x00000000004c2ecb in handle_target_event (error=0, client_data=0x0) at src/gdb/linux-nat.c:4655 I managed to come up with a test that reliably reproduces this. It spawns enough threads for the pid number space to wrap around, so could potentially take a while. On my box that's 4 seconds; on gcc110, a PPC box which has max_pid set to 65536, it's over 10 seconds. So I made the test compute how long that would take, and cap the time waited if it would be unreasonably long. Tested on x86_64 Fedora 20. gdb/ChangeLog: 2015-04-01 Pedro Alves <palves@redhat.com> * linux-thread-db.c (record_thread): Readd the thread to gdb's list if it was marked exited. gdb/testsuite/ChangeLog: 2015-04-01 Pedro Alves <palves@redhat.com> * gdb.threads/tid-reuse.c: New file. * gdb.threads/tid-reuse.exp: New file.
2015-04-01 12:38:06 +00:00
/* This testcase is part of GDB, the GNU debugger.
Copyright 2015-2016 Free Software Foundation, Inc.
Crash on thread id wrap around On GNU/Linux, if the target reuses the TID of a thread that GDB still has in its list marked as THREAD_EXITED, GDB crashes, like: (gdb) continue Continuing. src/gdb/thread.c:789: internal-error: set_running: Assertion `tp->state != THREAD_EXITED' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) FAIL: gdb.threads/tid-reuse.exp: continue to breakpoint: after_reuse_time (GDB internal error) Here: (top-gdb) bt #0 internal_error (file=0x953dd8 "src/gdb/thread.c", line=789, fmt=0x953da0 "%s: Assertion `%s' failed.") at src/gdb/common/errors.c:54 #1 0x0000000000638514 in set_running (ptid=..., running=1) at src/gdb/thread.c:789 #2 0x00000000004bda42 in linux_handle_extended_wait (lp=0x16f5760, status=0, stopping=0) at src/gdb/linux-nat.c:2114 #3 0x00000000004bfa24 in linux_nat_filter_event (lwpid=20570, status=198015) at src/gdb/linux-nat.c:3127 #4 0x00000000004c070e in linux_nat_wait_1 (ops=0xe193d0, ptid=..., ourstatus=0x7fffffffd2c0, target_options=1) at src/gdb/linux-nat.c:3478 #5 0x00000000004c1015 in linux_nat_wait (ops=0xe193d0, ptid=..., ourstatus=0x7fffffffd2c0, target_options=1) at src/gdb/linux-nat.c:3722 #6 0x00000000004c92d2 in thread_db_wait (ops=0xd80b60 <thread_db_ops>, ptid=..., ourstatus=0x7fffffffd2c0, options=1) at src/gdb/linux-thread-db.c:1525 #7 0x000000000066db43 in delegate_wait (self=0xd80b60 <thread_db_ops>, arg1=..., arg2=0x7fffffffd2c0, arg3=1) at src/gdb/target-delegates.c:116 #8 0x000000000067e54b in target_wait (ptid=..., status=0x7fffffffd2c0, options=1) at src/gdb/target.c:2206 #9 0x0000000000625111 in fetch_inferior_event (client_data=0x0) at src/gdb/infrun.c:3275 #10 0x0000000000648a3b in inferior_event_handler (event_type=INF_REG_EVENT, client_data=0x0) at src/gdb/inf-loop.c:56 #11 0x00000000004c2ecb in handle_target_event (error=0, client_data=0x0) at src/gdb/linux-nat.c:4655 I managed to come up with a test that reliably reproduces this. It spawns enough threads for the pid number space to wrap around, so could potentially take a while. On my box that's 4 seconds; on gcc110, a PPC box which has max_pid set to 65536, it's over 10 seconds. So I made the test compute how long that would take, and cap the time waited if it would be unreasonably long. Tested on x86_64 Fedora 20. gdb/ChangeLog: 2015-04-01 Pedro Alves <palves@redhat.com> * linux-thread-db.c (record_thread): Readd the thread to gdb's list if it was marked exited. gdb/testsuite/ChangeLog: 2015-04-01 Pedro Alves <palves@redhat.com> * gdb.threads/tid-reuse.c: New file. * gdb.threads/tid-reuse.exp: New file.
2015-04-01 12:38:06 +00:00
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#define _GNU_SOURCE
#include <assert.h>
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <limits.h>
/* How many threads fit in the target's thread number space. */
long tid_max = -1;
/* Number of threads spawned. */
unsigned long thread_counter;
/* How long it takes to spawn as many threads as fits in the thread
number space. On systems where thread IDs are just monotonically
incremented, this is enough for the tid numbers to wrap around. On
targets that randomize thread IDs, this is enough time to give each
number in the thread number space some chance of reuse. It'll be
capped to a lower value if we can't compute it. */
unsigned int reuse_time = -1;
void *
do_nothing_thread_func (void *arg)
{
usleep (1);
return NULL;
}
void *
spawner_thread_func (void *arg)
{
while (1)
{
pthread_t child;
int rc;
thread_counter++;
rc = pthread_create (&child, NULL, do_nothing_thread_func, NULL);
assert (rc == 0);
rc = pthread_join (child, NULL);
assert (rc == 0);
}
return NULL;
}
/* Called after the program is done counting number of spawned threads
for a period, to compute REUSE_TIME. */
void
after_count (void)
{
}
/* Called after enough time has passed for TID reuse to occur. */
void
after_reuse_time (void)
{
}
#ifdef __linux__
/* Get the running system's configured pid_max. */
static int
linux_proc_get_pid_max (void)
{
static const char filename[] ="/proc/sys/kernel/pid_max";
FILE *file;
char buf[100];
int retval = -1;
file = fopen (filename, "r");
if (file == NULL)
{
fprintf (stderr, "unable to open %s\n", filename);
return -1;
}
if (fgets (buf, sizeof (buf), file) != NULL)
retval = strtol (buf, NULL, 10);
fclose (file);
return retval;
}
#endif
int
main (int argc, char *argv[])
{
pthread_t child;
int rc;
unsigned int reuse_time_raw = 0;
rc = pthread_create (&child, NULL, spawner_thread_func, NULL);
assert (rc == 0);
#define COUNT_TIME 2
sleep (COUNT_TIME);
#ifdef __linux__
tid_max = linux_proc_get_pid_max ();
#endif
/* If we don't know how many threads it would take to use the whole
number space on this system, just run the test for a bit. */
if (tid_max > 0)
{
reuse_time_raw = tid_max / ((float) thread_counter / COUNT_TIME) + 0.5;
/* Give it a bit more, just in case. */
reuse_time = reuse_time_raw + 3;
}
/* 4 seconds were sufficient on the machine this was first observed,
an Intel i7-2620M @ 2.70GHz running Linux 3.18.7, with
pid_max=32768. Going forward, as machines get faster, this will
need less time, unless pid_max is set to a very high number. To
avoid unreasonably long test time, cap to an upper bound. */
if (reuse_time > 60)
reuse_time = 60;
printf ("thread_counter=%lu, tid_max = %ld, reuse_time_raw=%u, reuse_time=%u\n",
thread_counter, tid_max, reuse_time_raw, reuse_time);
after_count ();
sleep (reuse_time);
after_reuse_time ();
return 0;
}