| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20251113111039.22701-4-feng.tang@linux.alibaba.com>
Date: Thu, 13 Nov 2025 19:10:38 +0800
From: Feng Tang <feng.tang@...ux.alibaba.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Petr Mladek <pmladek@...e.com>,
Lance Yang <ioworker0@...il.com>,
Jonathan Corbet <corbet@....net>,
paulmck@...nel.org,
Steven Rostedt <rostedt@...dmis.org>,
linux-kernel@...r.kernel.org
Cc: Feng Tang <feng.tang@...ux.alibaba.com>
Subject: [PATCH v2 3/4] watchdog: add sys_info sysctls to dump sys info on system lockup
When soft/hard lockup happens, developers may need different kinds of
system information (call-stacks, memory info, locks, etc.) to help
debugging.
Add 'softlockup_sys_info' and 'hardlockup_sys_info' sysctl knobs to
take human readable string like "tasks,mem,timers,locks,ftrace,...",
and when system lockup happens, all requested information will be
printed out. (refer kernel/sys_info.c for more details).
Signed-off-by: Feng Tang <feng.tang@...ux.alibaba.com>
---
Documentation/admin-guide/sysctl/kernel.rst | 5 +++
kernel/watchdog.c | 44 +++++++++++++++++++--
2 files changed, 46 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index 45b4408dad31..176520283f1a 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -582,6 +582,11 @@ if leaking kernel pointer values to unprivileged users is a concern.
When ``kptr_restrict`` is set to 2, kernel pointers printed using
%pK will be replaced with 0s regardless of privileges.
+softlockup_sys_info & hardlockup_sys_info
+=========================================
+A comma separated list of extra system information to be dumped when
+soft/hard lockup is detected, for example, "tasks,mem,timers,locks,...".
+Refer 'panic_sys_info' section below for more details.
modprobe
========
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 659f5844393c..bbd11562e4c4 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -25,6 +25,7 @@
#include <linux/stop_machine.h>
#include <linux/sysctl.h>
#include <linux/tick.h>
+#include <linux/sys_info.h>
#include <linux/sched/clock.h>
#include <linux/sched/debug.h>
@@ -65,6 +66,13 @@ int __read_mostly sysctl_hardlockup_all_cpu_backtrace;
unsigned int __read_mostly hardlockup_panic =
IS_ENABLED(CONFIG_BOOTPARAM_HARDLOCKUP_PANIC);
+/*
+ * bitmasks to control what kinds of system info to be printed when
+ * hard lockup is detected, it could be task, memory, lock etc.
+ * Refer include/linux/sys_info.h for detailed bit definition.
+ */
+static unsigned long hardlockup_si_mask;
+
#ifdef CONFIG_SYSFS
static unsigned int hardlockup_count;
@@ -178,11 +186,15 @@ static void watchdog_hardlockup_kick(void)
void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)
{
+ int hardlockup_all_cpu_backtrace;
+
if (per_cpu(watchdog_hardlockup_touched, cpu)) {
per_cpu(watchdog_hardlockup_touched, cpu) = false;
return;
}
+ hardlockup_all_cpu_backtrace = (hardlockup_si_mask & SYS_INFO_ALL_BT) ?
+ 1 : sysctl_hardlockup_all_cpu_backtrace;
/*
* Check for a hardlockup by making sure the CPU's timer
* interrupt is incrementing. The timer interrupt should have
@@ -205,7 +217,7 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)
* Prevent multiple hard-lockup reports if one cpu is already
* engaged in dumping all cpu back traces.
*/
- if (sysctl_hardlockup_all_cpu_backtrace) {
+ if (hardlockup_all_cpu_backtrace) {
if (test_and_set_bit_lock(0, &hard_lockup_nmi_warn))
return;
}
@@ -234,12 +246,13 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)
trigger_single_cpu_backtrace(cpu);
}
- if (sysctl_hardlockup_all_cpu_backtrace) {
+ if (hardlockup_all_cpu_backtrace) {
trigger_allbutcpu_cpu_backtrace(cpu);
if (!hardlockup_panic)
clear_bit_unlock(0, &hard_lockup_nmi_warn);
}
+ sys_info(hardlockup_si_mask & ~SYS_INFO_ALL_BT);
if (hardlockup_panic)
nmi_panic(regs, "Hard LOCKUP");
@@ -330,6 +343,13 @@ static void lockup_detector_update_enable(void)
int __read_mostly sysctl_softlockup_all_cpu_backtrace;
#endif
+/*
+ * bitmasks to control what kinds of system info to be printed when
+ * soft lockup is detected, it could be task, memory, lock etc.
+ * Refer include/linux/sys_info.h for detailed bit definition.
+ */
+static unsigned long softlockup_si_mask;
+
static struct cpumask watchdog_allowed_mask __read_mostly;
/* Global variables, exported for sysctl */
@@ -746,7 +766,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
unsigned long touch_ts, period_ts, now;
struct pt_regs *regs = get_irq_regs();
int duration;
- int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace;
+ int softlockup_all_cpu_backtrace;
unsigned long flags;
if (!watchdog_enabled)
@@ -758,6 +778,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
if (panic_in_progress())
return HRTIMER_NORESTART;
+ softlockup_all_cpu_backtrace = (softlockup_si_mask & SYS_INFO_ALL_BT) ?
+ 1 : sysctl_softlockup_all_cpu_backtrace;
+
watchdog_hardlockup_kick();
/* kick the softlockup detector */
@@ -846,6 +869,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
}
add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
+ sys_info(softlockup_si_mask & ~SYS_INFO_ALL_BT);
if (softlockup_panic)
panic("softlockup: hung tasks");
}
@@ -1197,6 +1221,13 @@ static const struct ctl_table watchdog_sysctls[] = {
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
+ {
+ .procname = "softlockup_sys_info",
+ .data = &softlockup_si_mask,
+ .maxlen = sizeof(softlockup_si_mask),
+ .mode = 0644,
+ .proc_handler = sysctl_sys_info_handler,
+ },
#ifdef CONFIG_SMP
{
.procname = "softlockup_all_cpu_backtrace",
@@ -1219,6 +1250,13 @@ static const struct ctl_table watchdog_sysctls[] = {
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
+ {
+ .procname = "hardlockup_sys_info",
+ .data = &hardlockup_si_mask,
+ .maxlen = sizeof(hardlockup_si_mask),
+ .mode = 0644,
+ .proc_handler = sysctl_sys_info_handler,
+ },
#ifdef CONFIG_SMP
{
.procname = "hardlockup_all_cpu_backtrace",
--
2.43.5
Powered by blists - more mailing lists