[OpenWrt-Devel] [PATCH 4/4] build: Add additional kernel debug options

[Hauke Mehrtens]

Make it possible to activate some additional kernel debug options.
This can be used to debug some problems in kernel drivers.

Signed-off-by: Hauke Mehrtens <hauke.mehrtens at intel.com>
---
 config/Config-kernel.in          | 68 ++++++++++++++++++++++++++++++++
 target/linux/generic/config-4.14 |  5 +++
 target/linux/generic/config-4.19 |  5 +++
 3 files changed, 78 insertions(+)

diff --git a/config/Config-kernel.in b/config/Config-kernel.in
index 8e9e3518bf..4330d9fa5c 100644
--- a/config/Config-kernel.in
+++ b/config/Config-kernel.in
@@ -377,6 +377,74 @@ config KERNEL_PROVE_LOCKING
 	select KERNEL_DEBUG_KERNEL
 	default n
 
+config KERNEL_LOCKUP_DETECTOR
+	bool "Compile the kernel with detect Hard and Soft Lockups"
+	depends on KERNEL_DEBUG_KERNEL
+	help
+	  Say Y here to enable the kernel to act as a watchdog to detect
+	  hard and soft lockups.
+
+	  Softlockups are bugs that cause the kernel to loop in kernel
+	  mode for more than 20 seconds, without giving other tasks a
+	  chance to run.  The current stack trace is displayed upon
+	  detection and the system will stay locked up.
+
+	  Hardlockups are bugs that cause the CPU to loop in kernel mode
+	  for more than 10 seconds, without letting other interrupts have a
+	  chance to run.  The current stack trace is displayed upon detection
+	  and the system will stay locked up.
+
+	  The overhead should be minimal.  A periodic hrtimer runs to
+	  generate interrupts and kick the watchdog task every 4 seconds.
+	  An NMI is generated every 10 seconds or so to check for hardlockups.
+
+	  The frequency of hrtimer and NMI events and the soft and hard lockup
+	  thresholds can be controlled through the sysctl watchdog_thresh.
+
+config KERNEL_DETECT_HUNG_TASK
+	bool "Compile the kernel with detect Hung Tasks"
+	depends on KERNEL_DEBUG_KERNEL
+	default KERNEL_LOCKUP_DETECTOR
+	help
+	  Say Y here to enable the kernel to detect "hung tasks",
+	  which are bugs that cause the task to be stuck in
+	  uninterruptible "D" state indefinitely.
+
+	  When a hung task is detected, the kernel will print the
+	  current stack trace (which you should report), but the
+	  task will stay in uninterruptible state. If lockdep is
+	  enabled then all held locks will also be reported. This
+	  feature has negligible overhead.
+
+config KERNEL_WQ_WATCHDOG
+	bool "Compile the kernel with detect Workqueue Stalls"
+	depends on KERNEL_DEBUG_KERNEL
+	help
+	  Say Y here to enable stall detection on workqueues.  If a
+	  worker pool doesn't make forward progress on a pending work
+	  item for over a given amount of time, 30s by default, a
+	  warning message is printed along with dump of workqueue
+	  state.  This can be configured through kernel parameter
+	  "workqueue.watchdog_thresh" and its sysfs counterpart.
+
+config KERNEL_DEBUG_ATOMIC_SLEEP
+	bool "Compile the kernel with sleep inside atomic section checking"
+	depends on KERNEL_DEBUG_KERNEL
+	help
+	  If you say Y here, various routines which may sleep will become very
+	  noisy if they are called inside atomic sections: when a spinlock is
+	  held, inside an rcu read side critical section, inside preempt disabled
+	  sections, inside an interrupt, etc...
+
+config KERNEL_DEBUG_VM
+	bool "Compile the kernel with debug VM"
+	depends on KERNEL_DEBUG_KERNEL
+	help
+	  Enable this to turn on extended checks in the virtual-memory system
+          that may impact performance.
+
+	  If unsure, say N.
+
 config KERNEL_PRINTK_TIME
 	bool "Enable printk timestamps"
 	default y
diff --git a/target/linux/generic/config-4.14 b/target/linux/generic/config-4.14
index 5a9b82db80..d1ce30d2f7 100644
--- a/target/linux/generic/config-4.14
+++ b/target/linux/generic/config-4.14
@@ -594,6 +594,7 @@ CONFIG_BLOCK=y
 # CONFIG_BONDING is not set
 # CONFIG_BOOKE_WDT is not set
 CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT=3
+# CONFIG_BOOTPARAM_HUNG_TASK_PANIC is not set
 # CONFIG_BOOT_PRINTK_DELAY is not set
 CONFIG_BOOT_RAW=y
 CONFIG_BPF=y
@@ -1073,6 +1074,9 @@ CONFIG_DEBUG_KERNEL=y
 # CONFIG_DEBUG_UART_BCM63XX is not set
 # CONFIG_DEBUG_VIRTUAL is not set
 # CONFIG_DEBUG_VM is not set
+# CONFIG_DEBUG_VM_PGFLAGS is not set
+# CONFIG_DEBUG_VM_RB is not set
+# CONFIG_DEBUG_VM_VMACACHE is not set
 # CONFIG_DEBUG_WQ_FORCE_RR_CPU is not set
 # CONFIG_DEBUG_WW_MUTEX_SLOWPATH is not set
 # CONFIG_DEBUG_WX is not set
@@ -1081,6 +1085,7 @@ CONFIG_DEBUG_KERNEL=y
 CONFIG_DEFAULT_CUBIC=y
 CONFIG_DEFAULT_DEADLINE=y
 CONFIG_DEFAULT_HOSTNAME="(none)"
+CONFIG_DEFAULT_HUNG_TASK_TIMEOUT=120
 CONFIG_DEFAULT_IOSCHED="deadline"
 CONFIG_DEFAULT_MMAP_MIN_ADDR=4096
 # CONFIG_DEFAULT_NOOP is not set
diff --git a/target/linux/generic/config-4.19 b/target/linux/generic/config-4.19
index 372cad70a6..153520c396 100644
--- a/target/linux/generic/config-4.19
+++ b/target/linux/generic/config-4.19
@@ -617,6 +617,7 @@ CONFIG_BLOCK=y
 # CONFIG_BONDING is not set
 # CONFIG_BOOKE_WDT is not set
 CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT=3
+# CONFIG_BOOTPARAM_HUNG_TASK_PANIC is not set
 # CONFIG_BOOT_PRINTK_DELAY is not set
 CONFIG_BOOT_RAW=y
 CONFIG_BPF=y
@@ -1131,6 +1132,9 @@ CONFIG_DEBUG_KERNEL=y
 # CONFIG_DEBUG_UART_BCM63XX is not set
 # CONFIG_DEBUG_VIRTUAL is not set
 # CONFIG_DEBUG_VM is not set
+# CONFIG_DEBUG_VM_PGFLAGS is not set
+# CONFIG_DEBUG_VM_RB is not set
+# CONFIG_DEBUG_VM_VMACACHE is not set
 # CONFIG_DEBUG_WQ_FORCE_RR_CPU is not set
 # CONFIG_DEBUG_WW_MUTEX_SLOWPATH is not set
 # CONFIG_DEBUG_WX is not set
@@ -1139,6 +1143,7 @@ CONFIG_DEBUG_KERNEL=y
 CONFIG_DEFAULT_CUBIC=y
 CONFIG_DEFAULT_DEADLINE=y
 CONFIG_DEFAULT_HOSTNAME="(none)"
+CONFIG_DEFAULT_HUNG_TASK_TIMEOUT=120
 CONFIG_DEFAULT_IOSCHED="deadline"
 CONFIG_DEFAULT_MMAP_MIN_ADDR=4096
 # CONFIG_DEFAULT_NOOP is not set
-- 
2.17.1


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