From b63343207da21179d82df933f42a1725a53b9a63 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 21 Feb 2023 19:02:35 +0000 Subject: locktorture: Add nested_[un]lock() hooks and nlocks parameter In order to extend locktorture to support lock nesting, add nested_lock() and nested_unlock() hooks to the torture ops. These take a 32bit lockset mask which is generated at random, so some number of locks will be taken before the main lock is taken and released afterwards. Additionally, add nested_locks module parameter to allow specifying the number of nested locks to be used. This has been helpful to uncover issues in the proxy-exec series development. This was inspired by locktorture extensions originally implemented by Connor O'Brien, for stress testing the proxy-execution series: https://lore.kernel.org/lkml/20221003214501.2050087-12-connoro@google.com/ Cc: Davidlohr Bueso Cc: "Paul E. McKenney" Cc: Josh Triplett Cc: Joel Fernandes Cc: Juri Lelli Cc: Valentin Schneider Cc: Dietmar Eggemann Cc: kernel-team@android.com Reviewed-by: Davidlohr Bueso Co-developed-by: Connor O'Brien Signed-off-by: Connor O'Brien Signed-off-by: John Stultz Signed-off-by: Paul E. McKenney --- kernel/locking/locktorture.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'kernel/locking/locktorture.c') diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index f04b1978899d..a8519af25ece 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -51,6 +51,9 @@ torture_param(int, rt_boost, 2, torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens."); torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); +torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)"); +/* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */ +#define MAX_NESTED_LOCKS 8 static char *torture_type = "spin_lock"; module_param(torture_type, charp, 0444); @@ -79,10 +82,12 @@ static void lock_torture_cleanup(void); struct lock_torture_ops { void (*init)(void); void (*exit)(void); + int (*nested_lock)(int tid, u32 lockset); int (*writelock)(int tid); void (*write_delay)(struct torture_random_state *trsp); void (*task_boost)(struct torture_random_state *trsp); void (*writeunlock)(int tid); + void (*nested_unlock)(int tid, u32 lockset); int (*readlock)(int tid); void (*read_delay)(struct torture_random_state *trsp); void (*readunlock)(int tid); @@ -684,6 +689,7 @@ static int lock_torture_writer(void *arg) struct lock_stress_stats *lwsp = arg; int tid = lwsp - cxt.lwsa; DEFINE_TORTURE_RANDOM(rand); + u32 lockset_mask; VERBOSE_TOROUT_STRING("lock_torture_writer task started"); set_user_nice(current, MAX_NICE); @@ -692,7 +698,10 @@ static int lock_torture_writer(void *arg) if ((torture_random(&rand) & 0xfffff) == 0) schedule_timeout_uninterruptible(1); + lockset_mask = torture_random(&rand); cxt.cur_ops->task_boost(&rand); + if (cxt.cur_ops->nested_lock) + cxt.cur_ops->nested_lock(tid, lockset_mask); cxt.cur_ops->writelock(tid); if (WARN_ON_ONCE(lock_is_write_held)) lwsp->n_lock_fail++; @@ -705,6 +714,8 @@ static int lock_torture_writer(void *arg) lock_is_write_held = false; WRITE_ONCE(last_lock_release, jiffies); cxt.cur_ops->writeunlock(tid); + if (cxt.cur_ops->nested_unlock) + cxt.cur_ops->nested_unlock(tid, lockset_mask); stutter_wait("lock_torture_writer"); } while (!torture_must_stop()); @@ -845,11 +856,11 @@ lock_torture_print_module_parms(struct lock_torture_ops *cur_ops, const char *tag) { pr_alert("%s" TORTURE_FLAG - "--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n", + "--- %s%s: nwriters_stress=%d nreaders_stress=%d nested_locks=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n", torture_type, tag, cxt.debug_lock ? " [debug]": "", - cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval, - verbose, shuffle_interval, stutter, shutdown_secs, - onoff_interval, onoff_holdoff); + cxt.nrealwriters_stress, cxt.nrealreaders_stress, + nested_locks, stat_interval, verbose, shuffle_interval, + stutter, shutdown_secs, onoff_interval, onoff_holdoff); } static void lock_torture_cleanup(void) @@ -1068,6 +1079,10 @@ static int __init lock_torture_init(void) } } + /* cap nested_locks to MAX_NESTED_LOCKS */ + if (nested_locks > MAX_NESTED_LOCKS) + nested_locks = MAX_NESTED_LOCKS; + if (cxt.cur_ops->readlock) { reader_tasks = kcalloc(cxt.nrealreaders_stress, sizeof(reader_tasks[0]), -- cgit