Messages in this thread | | | Date | Wed, 20 Feb 2013 16:20:15 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH v4] lockdep: check that no locks held at freeze time |
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On Wed, 20 Feb 2013 16:17:39 -0800 Mandeep Singh Baines <msb@chromium.org> wrote:
> On Wed, Feb 20, 2013 at 3:24 PM, Andrew Morton > <akpm@linux-foundation.org> wrote: > > On Wed, 20 Feb 2013 15:17:16 -0800 > > Mandeep Singh Baines <msb@chromium.org> wrote: > > > >> We shouldn't try_to_freeze if locks are held. > >> > >> ... > >> > >> @@ -43,6 +44,9 @@ extern void thaw_kernel_threads(void); > >> > >> + if (!(current->flags & PF_NOFREEZE)) > >> + debug_check_no_locks_held(current, > >> + > >> "lock held while trying to freeze"); > >> ... > >> > >> + debug_check_no_locks_held(tsk, "lock held at task exit time"); > > > > There doesn't seem much point in adding the `msg' to > > debug_check_no_locks_held() - the dump_stack() in > > print_held_locks_bug() will tell us the same thing. Maybe just change > > dump_stack() can be confusing when there is inlining. On occasion I've > looked at the wrong mutex_lock, for example, when there was another > mutex_lock that was inlined. Of course, you can start objdump and > verify the offsets. But that requires that you have the object file. > You could have a try_to_freeze added to do_exit. I was thinking of > adding another locks_held in the return from syscall path.
Backtraces aren't *that* bad. We'll easily be able to tell which of the two callsites triggered the trace.
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