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-rw-r--r--include/linux/workqueue.h5
-rw-r--r--kernel/printk.c2
-rw-r--r--kernel/sched/core.c1
-rw-r--r--kernel/workqueue.c79
-rw-r--r--kernel/workqueue_internal.h12
5 files changed, 98 insertions, 1 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 717975639378..623488fdc1f5 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -92,6 +92,9 @@ enum {
/* bit mask for work_busy() return values */
WORK_BUSY_PENDING = 1 << 0,
WORK_BUSY_RUNNING = 1 << 1,
+
+ /* maximum string length for set_worker_desc() */
+ WORKER_DESC_LEN = 24,
};
struct work_struct {
@@ -447,6 +450,8 @@ extern void workqueue_set_max_active(struct workqueue_struct *wq,
extern bool current_is_workqueue_rescuer(void);
extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
extern unsigned int work_busy(struct work_struct *work);
+extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
+extern void print_worker_info(const char *log_lvl, struct task_struct *task);
/**
* queue_work - queue work on a workqueue
diff --git a/kernel/printk.c b/kernel/printk.c
index e10ad515901f..96dcfcd9a2d4 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -2891,6 +2891,8 @@ void dump_stack_print_info(const char *log_lvl)
if (dump_stack_arch_desc_str[0] != '\0')
printk("%sHardware name: %s\n",
log_lvl, dump_stack_arch_desc_str);
+
+ print_worker_info(log_lvl, current);
}
/**
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c70a8814a767..5662f58f0b69 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4586,6 +4586,7 @@ void sched_show_task(struct task_struct *p)
task_pid_nr(p), ppid,
(unsigned long)task_thread_info(p)->flags);
+ print_worker_info(KERN_INFO, p);
show_stack(p, NULL);
}
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 154aa12af48e..4aa9f5bc6b2d 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -46,6 +46,7 @@
#include <linux/rculist.h>
#include <linux/nodemask.h>
#include <linux/moduleparam.h>
+#include <linux/uaccess.h>
#include "workqueue_internal.h"
@@ -2197,6 +2198,7 @@ __acquires(&pool->lock)
worker->current_work = NULL;
worker->current_func = NULL;
worker->current_pwq = NULL;
+ worker->desc_valid = false;
pwq_dec_nr_in_flight(pwq, work_color);
}
@@ -4365,6 +4367,83 @@ unsigned int work_busy(struct work_struct *work)
}
EXPORT_SYMBOL_GPL(work_busy);
+/**
+ * set_worker_desc - set description for the current work item
+ * @fmt: printf-style format string
+ * @...: arguments for the format string
+ *
+ * This function can be called by a running work function to describe what
+ * the work item is about. If the worker task gets dumped, this
+ * information will be printed out together to help debugging. The
+ * description can be at most WORKER_DESC_LEN including the trailing '\0'.
+ */
+void set_worker_desc(const char *fmt, ...)
+{
+ struct worker *worker = current_wq_worker();
+ va_list args;
+
+ if (worker) {
+ va_start(args, fmt);
+ vsnprintf(worker->desc, sizeof(worker->desc), fmt, args);
+ va_end(args);
+ worker->desc_valid = true;
+ }
+}
+
+/**
+ * print_worker_info - print out worker information and description
+ * @log_lvl: the log level to use when printing
+ * @task: target task
+ *
+ * If @task is a worker and currently executing a work item, print out the
+ * name of the workqueue being serviced and worker description set with
+ * set_worker_desc() by the currently executing work item.
+ *
+ * This function can be safely called on any task as long as the
+ * task_struct itself is accessible. While safe, this function isn't
+ * synchronized and may print out mixups or garbages of limited length.
+ */
+void print_worker_info(const char *log_lvl, struct task_struct *task)
+{
+ work_func_t *fn = NULL;
+ char name[WQ_NAME_LEN] = { };
+ char desc[WORKER_DESC_LEN] = { };
+ struct pool_workqueue *pwq = NULL;
+ struct workqueue_struct *wq = NULL;
+ bool desc_valid = false;
+ struct worker *worker;
+
+ if (!(task->flags & PF_WQ_WORKER))
+ return;
+
+ /*
+ * This function is called without any synchronization and @task
+ * could be in any state. Be careful with dereferences.
+ */
+ worker = probe_kthread_data(task);
+
+ /*
+ * Carefully copy the associated workqueue's workfn and name. Keep
+ * the original last '\0' in case the original contains garbage.
+ */
+ probe_kernel_read(&fn, &worker->current_func, sizeof(fn));
+ probe_kernel_read(&pwq, &worker->current_pwq, sizeof(pwq));
+ probe_kernel_read(&wq, &pwq->wq, sizeof(wq));
+ probe_kernel_read(name, wq->name, sizeof(name) - 1);
+
+ /* copy worker description */
+ probe_kernel_read(&desc_valid, &worker->desc_valid, sizeof(desc_valid));
+ if (desc_valid)
+ probe_kernel_read(desc, worker->desc, sizeof(desc) - 1);
+
+ if (fn || name[0] || desc[0]) {
+ printk("%sWorkqueue: %s %pf", log_lvl, name, fn);
+ if (desc[0])
+ pr_cont(" (%s)", desc);
+ pr_cont("\n");
+ }
+}
+
/*
* CPU hotplug.
*
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index 84ab6e1dc6fb..ad83c96b2ece 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -29,15 +29,25 @@ struct worker {
struct work_struct *current_work; /* L: work being processed */
work_func_t current_func; /* L: current_work's fn */
struct pool_workqueue *current_pwq; /* L: current_work's pwq */
+ bool desc_valid; /* ->desc is valid */
struct list_head scheduled; /* L: scheduled works */
+
+ /* 64 bytes boundary on 64bit, 32 on 32bit */
+
struct task_struct *task; /* I: worker task */
struct worker_pool *pool; /* I: the associated pool */
/* L: for rescuers */
- /* 64 bytes boundary on 64bit, 32 on 32bit */
+
unsigned long last_active; /* L: last active timestamp */
unsigned int flags; /* X: flags */
int id; /* I: worker id */
+ /*
+ * Opaque string set with work_set_desc(). Printed out with task
+ * dump for debugging - WARN, BUG, panic or sysrq.
+ */
+ char desc[WORKER_DESC_LEN];
+
/* used only by rescuers to point to the target workqueue */
struct workqueue_struct *rescue_wq; /* I: the workqueue to rescue */
};