[OpenWrt-Devel] [PATCH 4/4] build: Add additional kernel debug options
Alexandru Ardelean
ardeleanalex at gmail.com
Thu Feb 13 04:30:22 EST 2020
On Wed, Feb 12, 2020 at 12:50 PM Hauke Mehrtens
<hauke.mehrtens at intel.com> wrote:
>
> Make it possible to activate some additional kernel debug options.
> This can be used to debug some problems in kernel drivers.
>
Reviewed-by: Alexandru Ardelean <ardeleanalex at gmail.com>
> 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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