On Tue, Jul 02, 2019 at 05:53:35PM +0200, Thomas Gleixner wrote: > !current->mm is not a reliable indicator for kernel threads as they might > temporarily use a user mm. Check for PF_KTHREAD instead. > > Signed-off-by: Thomas Gleixner <t...@linutronix.de>
FWIW: Acked-by: Mark Rutland <mark.rutl...@arm.com> As a heads-up, I started looking into cleaning up bogus mm checks tree-wide, since there are a number that look suspicious (e.g. arm64's arch_dup_task_struct() and x86's __kernel_fpu_begin()). I was hoping to add an is_kthread(tsk) helper to push people in the right direction [1]. Thanks, Mark. [1] https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=sched/kthread-cleanup > --- > --- a/kernel/stacktrace.c > +++ b/kernel/stacktrace.c > @@ -228,7 +228,7 @@ unsigned int stack_trace_save_user(unsig > }; > > /* Trace user stack if not a kernel thread */ > - if (!current->mm) > + if (current->flags & PF_KTHREAD) > return 0; > > arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
