The function has a nice comment: /* * This function is called without any synchronization and @task * could be in any state. Be careful with dereferences. */
But a few lines later it blindly dereferences a few pointers. E.g. It can happen that the worker function is already done, then worker->current_pwq is NULL. Signed-off-by: Richard Weinberger <[email protected]> --- kernel/workqueue.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 7f5d4be..61382b9 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -4465,6 +4465,8 @@ void print_worker_info(const char *log_lvl, struct task_struct *task) * could be in any state. Be careful with dereferences. */ worker = probe_kthread_data(task); + if (!worker) + return; /* * Carefully copy the associated workqueue's workfn and name. Keep @@ -4472,7 +4474,13 @@ void print_worker_info(const char *log_lvl, struct task_struct *task) */ probe_kernel_read(&fn, &worker->current_func, sizeof(fn)); probe_kernel_read(&pwq, &worker->current_pwq, sizeof(pwq)); + if (!pwq) + goto print; + probe_kernel_read(&wq, &pwq->wq, sizeof(wq)); + if (!wq) + goto print; + probe_kernel_read(name, wq->name, sizeof(name) - 1); /* copy worker description */ @@ -4480,6 +4488,7 @@ void print_worker_info(const char *log_lvl, struct task_struct *task) if (desc_valid) probe_kernel_read(desc, worker->desc, sizeof(desc) - 1); +print: if (fn || name[0] || desc[0]) { printk("%sWorkqueue: %s %pf", log_lvl, name, fn); if (desc[0]) -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
