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| author | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-04-09 21:06:32 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-05-28 19:06:09 +0300 |
| commit | e8516c64fe97e27a28fd5bc65b616508ae0020cf (patch) | |
| tree | a8735dcac32c1d817849495ab010617213de8657 /kernel/torture.c | |
| parent | 140e53f20b159722903f0c87358bcd809aa9767e (diff) | |
| download | linux-e8516c64fe97e27a28fd5bc65b616508ae0020cf.tar.xz | |
rcutorture: Fix stutter_wait() return value and freelist checks
The stutter_wait() function is supposed to return true if it actually
waits and false otherwise, but it instead unconditionally returns false.
Which hides a bug in rcu_torture_writer() that fails to account for
the fact that one of the rcu_tortures[] array elements will normally be
referenced by rcu_torture_current, and thus not be on the freelist.
This commit therefore corrects the stutter_wait() return value and adds a
check for rcu_torture_current to rcu_torture_writer()'s check that things
get freed after everything goes quiescent. In addition, this commit
causes torture_stutter() to give a bit more than one second (instead of
only one jiffy) warning of the end of the stutter interval. Finally,
this commit disables long-delay readers and aggressive update-side
forward-progress checks while forward-progress testing is in flight.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel/torture.c')
| -rw-r--r-- | kernel/torture.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/kernel/torture.c b/kernel/torture.c index 17b2be9bde12..de0e0ecf88e1 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -578,10 +578,12 @@ static int stutter; bool stutter_wait(const char *title) { int spt; + bool ret = false; cond_resched_tasks_rcu_qs(); spt = READ_ONCE(stutter_pause_test); for (; spt; spt = READ_ONCE(stutter_pause_test)) { + ret = true; if (spt == 1) { schedule_timeout_interruptible(1); } else if (spt == 2) { @@ -592,7 +594,7 @@ bool stutter_wait(const char *title) } torture_shutdown_absorb(title); } - return !!spt; + return ret; } EXPORT_SYMBOL_GPL(stutter_wait); @@ -602,13 +604,20 @@ EXPORT_SYMBOL_GPL(stutter_wait); */ static int torture_stutter(void *arg) { + int wtime; + VERBOSE_TOROUT_STRING("torture_stutter task started"); do { if (!torture_must_stop() && stutter > 1) { - WRITE_ONCE(stutter_pause_test, 1); - schedule_timeout_interruptible(stutter - 1); + wtime = stutter; + if (stutter > HZ + 1) { + WRITE_ONCE(stutter_pause_test, 1); + wtime = stutter - HZ - 1; + schedule_timeout_interruptible(wtime); + wtime = HZ + 1; + } WRITE_ONCE(stutter_pause_test, 2); - schedule_timeout_interruptible(1); + schedule_timeout_interruptible(wtime); } WRITE_ONCE(stutter_pause_test, 0); if (!torture_must_stop()) |