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| author | Paul E. McKenney <paulmck@kernel.org> | 2021-12-28 15:59:38 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-02-01 17:24:39 -0800 |
| commit | 89440d2dad0cc2a781290470cb90402ebba481fc (patch) | |
| tree | ae1f9173e91043d0849844e8be545d086ca8254f /kernel/rcu | |
| parent | 02b51a1cf47977d8772c7dcc363ef6a1e6e59f21 (diff) | |
| download | linux-stable-89440d2dad0cc2a781290470cb90402ebba481fc.tar.gz linux-stable-89440d2dad0cc2a781290470cb90402ebba481fc.tar.bz2 linux-stable-89440d2dad0cc2a781290470cb90402ebba481fc.zip | |
rcutorture: Fix rcu_fwd_mutex deadlock
The rcu_torture_fwd_cb_hist() function acquires rcu_fwd_mutex, but is
invoked from rcutorture_oom_notify() function, which hold this same
mutex across this call. This commit fixes the resulting deadlock.
Reported-by: kernel test robot <oliver.sang@intel.com>
Tested-by: Oliver Sang <oliver.sang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/rcutorture.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index e99658efd97f..1c8f40b90f70 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -2180,7 +2180,6 @@ static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) if (rfp->n_launders_hist[i].n_launders > 0) break; - mutex_lock(&rcu_fwd_mutex); // Serialize histograms. pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):", __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat); gps_old = rfp->rcu_launder_gp_seq_start; @@ -2193,7 +2192,6 @@ static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) gps_old = gps; } pr_cont("\n"); - mutex_unlock(&rcu_fwd_mutex); } /* Callback function for continuous-flood RCU callbacks. */ @@ -2431,7 +2429,9 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) n_launders, n_launders_sa, n_max_gps, n_max_cbs, cver, gps); atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs); + mutex_lock(&rcu_fwd_mutex); // Serialize histograms. rcu_torture_fwd_cb_hist(rfp); + mutex_unlock(&rcu_fwd_mutex); } schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ tick_dep_clear_task(current, TICK_DEP_BIT_RCU); |