lkml.org 
[lkml]   [2018]   [Apr]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 7/9] trace_uprobe/sdt: Fix multiple update of same reference counter
Hi Ravi,

On 04/10, Ravi Bangoria wrote:
>
> > and what if __mmu_notifier_register() fails simply because signal_pending() == T?
> > see mm_take_all_locks().
> >
> > at first glance this all look suspicious and sub-optimal,
>
> Yes. I should have added checks for failure cases.
> Will fix them in v3.

And what can you do if it fails? Nothing except report the problem. But
signal_pending() is not the unlikely or error condition, it should not
cause the tracing errors.

Plus mm_take_all_locks() is very heavy... BTW, uprobe_mmap_callback() is
called unconditionally. Whatever it does, can we at least move it after
the no_uprobe_events() check? Can't we also check MMF_HAS_UPROBES?

Either way, I do not feel that mmu_notifier is the right tool... Did you
consider the uprobe_clear_state() hook we already have?

Oleg.

\
 
 \ /
  Last update: 2018-04-10 13:07    [W:0.052 / U:22.980 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site