From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
chao <chao@eero.com>, "Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 03/16] rcu: Panic after fixed number of stalls
Date: Thu, 5 Nov 2020 15:09:08 -0800 [thread overview]
Message-ID: <20201105230921.19017-3-paulmck@kernel.org> (raw)
In-Reply-To: <20201105230856.GA18904@paulmck-ThinkPad-P72>
From: chao <chao@eero.com>
Some stalls are transient, so that system fully recovers. This commit
therefore allows users to configure the number of stalls that must happen
in order to trigger kernel panic.
Signed-off-by: chao <chao@eero.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
include/linux/kernel.h | 1 +
kernel/rcu/tree_stall.h | 6 ++++++
kernel/sysctl.c | 11 +++++++++++
3 files changed, 18 insertions(+)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2f05e91..4b5fd3d 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -536,6 +536,7 @@ extern int panic_on_warn;
extern unsigned long panic_on_taint;
extern bool panic_on_taint_nousertaint;
extern int sysctl_panic_on_rcu_stall;
+extern int sysctl_max_rcu_stall_to_panic;
extern int sysctl_panic_on_stackoverflow;
extern bool crash_kexec_post_notifiers;
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index ca21d28..70d48c5 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -13,6 +13,7 @@
/* panic() on RCU Stall sysctl. */
int sysctl_panic_on_rcu_stall __read_mostly;
+int sysctl_max_rcu_stall_to_panic __read_mostly;
#ifdef CONFIG_PROVE_RCU
#define RCU_STALL_DELAY_DELTA (5 * HZ)
@@ -106,6 +107,11 @@ early_initcall(check_cpu_stall_init);
/* If so specified via sysctl, panic, yielding cleaner stall-warning output. */
static void panic_on_rcu_stall(void)
{
+ static int cpu_stall;
+
+ if (++cpu_stall < sysctl_max_rcu_stall_to_panic)
+ return;
+
if (sysctl_panic_on_rcu_stall)
panic("RCU Stall\n");
}
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index afad085..c9fbdd8 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2650,6 +2650,17 @@ static struct ctl_table kern_table[] = {
.extra2 = SYSCTL_ONE,
},
#endif
+#if defined(CONFIG_TREE_RCU)
+ {
+ .procname = "max_rcu_stall_to_panic",
+ .data = &sysctl_max_rcu_stall_to_panic,
+ .maxlen = sizeof(sysctl_max_rcu_stall_to_panic),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = SYSCTL_ONE,
+ .extra2 = SYSCTL_INT_MAX,
+ },
+#endif
#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
{
.procname = "stack_erasing",
--
2.9.5
next prev parent reply other threads:[~2020-11-05 23:10 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-05 23:08 [PATCH tip/core/rcu 0/16] Miscellaneous fixes for v5.11 Paul E. McKenney
2020-11-05 23:09 ` [PATCH tip/core/rcu 01/16] rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 02/16] x86/smpboot: Move rcu_cpu_starting() earlier paulmck
2020-11-05 23:09 ` paulmck [this message]
2020-11-05 23:09 ` [PATCH tip/core/rcu 04/16] list.h: Update comment to explicitly note circular lists paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 05/16] rcu: Implement rcu_segcblist_is_offloaded() config dependent paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 06/16] rcu: Fix single-CPU check in rcu_blocking_is_gp() paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 07/16] rcu: Clarify nocb kthreads naming in RCU_NOCB_CPU config paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 08/16] rcu/tree: Add a warning if CPU being onlined did not report QS already paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 09/16] rcu/tree: Make struct kernel_param_ops definitions const paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 10/16] rcu,ftrace: Fix ftrace recursion paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 11/16] rcu/tree: nocb: Avoid raising softirq for offloaded ready-to-execute CBs paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 12/16] rcu: Prevent lockdep-RCU splats on lock acquisition/release paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 13/16] rcu: Fix a typo in rcu_blocking_is_gp() header comment paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 14/16] rcu: Do not report strict GPs for outgoing CPUs paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 15/16] rcu/tree: Defer kvfree_rcu() allocation to a clean context paulmck
2020-11-05 23:09 ` [PATCH tip/core/rcu 16/16] srcu: Take early exit on memory-allocation failure paulmck
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