diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/tst-bz21269.c | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/tst-bz21269.c b/sysdeps/unix/sysv/linux/i386/tst-bz21269.c index 1850240..51d4a1b 100644 --- a/sysdeps/unix/sysv/linux/i386/tst-bz21269.c +++ b/sysdeps/unix/sysv/linux/i386/tst-bz21269.c @@ -135,7 +135,14 @@ threadproc (void *ctx) { while (1) { - futex ((int *) &ftx, FUTEX_WAIT, 1, NULL, NULL, 0); + /* Continue to wait here until we've successfully waited, unless + we're supposed to be clearing the LDT already. */ + while (futex ((int *) &ftx, FUTEX_WAIT, 1, NULL, NULL, 0) < 0) + if (atomic_load (&ftx) >= 2) + break; + + /* Normally there's time to hit this busy loop and wait for ftx + to be set to 2. */ while (atomic_load (&ftx) != 2) { if (atomic_load (&ftx) >= 3) @@ -189,7 +196,14 @@ do_test (void) if (sigsetjmp (jmpbuf, 1) != 0) continue; - /* Make sure the thread is ready after the last test. */ + /* We may have longjmp'd before triggering the thread. If so, + trigger the thread now and wait for it. */ + if (atomic_load (&ftx) == 1) + atomic_store (&ftx, 2); + + /* Make sure the thread is ready after the last test. FTX is + initially zero for the first loop, and set to zero each time + the thread clears the LDT. */ while (atomic_load (&ftx) != 0) ; @@ -207,15 +221,24 @@ do_test (void) xmodify_ldt (0x11, &desc, sizeof (desc)); - /* Arm the thread. */ - ftx = 1; - futex ((int*) &ftx, FUTEX_WAKE, 0, NULL, NULL, 0); + /* Arm the thread. We loop here until we've woken up one thread. */ + atomic_store (&ftx, 1); + while (futex ((int*) &ftx, FUTEX_WAKE, 1, NULL, NULL, 0) < 1) + ; + + /* Give the thread a chance to get into it's busy loop. */ + usleep (5); + /* At *ANY* point after this instruction, we may segfault and + longjump back to the top of the loop. The intention is to + have this happen when the thread clears the LDT, but it could + happen elsewhen. */ asm volatile ("mov %0, %%ss" : : "r" (0x7)); /* Fire up thread modify_ldt call. */ atomic_store (&ftx, 2); + /* And wait for it. */ while (atomic_load (&ftx) != 0) ; |