From: Minchan Kim <minchan@kernel.org>
To: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-api@vger.kernel.org, Suren Baghdasaryan <surenb@google.com>,
Tim Murray <timmurray@google.com>,
Daniel Colascione <dancol@google.com>,
Sandeep Patil <sspatil@google.com>,
Sonny Rao <sonnyrao@google.com>,
Brian Geffon <bgeffon@google.com>, Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Shakeel Butt <shakeelb@google.com>,
John Dias <joaodias@google.com>,
Joel Fernandes <joel@joelfernandes.org>,
Jann Horn <jannh@google.com>,
alexander.h.duyck@linux.intel.com, sj38.park@gmail.com
Subject: Re: [PATCH v7 6/7] mm/madvise: employ mmget_still_valid for write lock
Date: Tue, 10 Mar 2020 15:28:15 -0700 [thread overview]
Message-ID: <20200310222815.GD72963@google.com> (raw)
In-Reply-To: <20200309123045.o4cwni3ra6zq6ha2@butterfly.localdomain>
On Mon, Mar 09, 2020 at 01:30:45PM +0100, Oleksandr Natalenko wrote:
> On Fri, Mar 06, 2020 at 05:03:50PM +0100, Vlastimil Babka wrote:
> > On 3/6/20 2:03 PM, Oleksandr Natalenko wrote:
> > > Hello.
> > >
> > > On Fri, Mar 06, 2020 at 01:52:07PM +0100, Vlastimil Babka wrote:
> > >> > diff --git a/mm/madvise.c b/mm/madvise.c
> > >> > index e794367f681e..e77c6c1fad34 100644
> > >> > --- a/mm/madvise.c
> > >> > +++ b/mm/madvise.c
> > >> > @@ -1118,6 +1118,8 @@ int do_madvise(struct task_struct *target_task, struct mm_struct *mm,
> > >> > if (write) {
> > >> > if (down_write_killable(&mm->mmap_sem))
> > >> > return -EINTR;
> > >> > + if (current->mm != mm && !mmget_still_valid(mm))
> > >> > + goto skip_mm;
> > >>
> > >> This will return 0, is that correct? Shoudln't there be a similar error e.g. as
> > >> when finding the task by pid fails (-ESRCH ?), because IIUC the task here is
> > >> going away and dumping the core?
> > >
> > > Yeah.
> > >
> > > Something like this then:
> > >
> > > ===
> > > diff --git a/mm/madvise.c b/mm/madvise.c
> > > index 48d1da08c160..7ed2f4d13924 100644
> > > --- a/mm/madvise.c
> > > +++ b/mm/madvise.c
> > > @@ -1122,6 +1122,10 @@ int do_madvise(struct task_struct *target_task, struct mm_struct *mm,
> > > if (write) {
> > > if (down_write_killable(&mm->mmap_sem))
> > > return -EINTR;
> > > + if (current->mm != mm && !mmget_still_valid(mm)) {
> > > + error = -ESRCH;
> > > + goto skip_mm;
> > > + }
> > > } else {
> > > down_read(&mm->mmap_sem);
> > > }
> > > @@ -1173,6 +1177,7 @@ int do_madvise(struct task_struct *target_task, struct mm_struct *mm,
> > > }
> > > out:
> > > blk_finish_plug(&plug);
> > > +skip_mm:
> > > if (write)
> > > up_write(&mm->mmap_sem);
> > > else
> > >
> > > ===
> > >
> > > ?
> >
> > Yep, thanks.
> >
>
> Minchan, shall you take this change into the next submission, or you'd
> prefer me sending it to you as a new patch?
I should send patchset again so I will take it.
Thanks!
next prev parent reply other threads:[~2020-03-10 22:28 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-02 19:36 [PATCH v7 0/7] introduce memory hinting API for external process Minchan Kim
2020-03-02 19:36 ` [PATCH v7 1/7] mm: pass task and mm to do_madvise Minchan Kim
2020-03-05 15:48 ` Vlastimil Babka
2020-05-08 18:21 ` Minchan Kim
2020-03-02 19:36 ` [PATCH v7 2/7] mm: introduce external memory hinting API Minchan Kim
2020-03-03 10:33 ` kbuild test robot
2020-03-03 14:57 ` Minchan Kim
2020-03-05 18:15 ` Vlastimil Babka
2020-03-10 22:20 ` Minchan Kim
2020-03-11 0:36 ` Minchan Kim
2020-03-12 12:40 ` Vlastimil Babka
2020-03-12 20:23 ` Minchan Kim
2020-05-08 18:33 ` Minchan Kim
2020-03-02 19:36 ` [PATCH v7 3/7] mm: check fatal signal pending of target process Minchan Kim
2020-03-06 10:22 ` Vlastimil Babka
2020-03-10 22:24 ` Minchan Kim
2020-03-02 19:36 ` [PATCH v7 4/7] pid: move pidfd_get_pid function to pid.c Minchan Kim
2020-03-06 10:57 ` Vlastimil Babka
2020-03-06 11:14 ` Christian Brauner
2020-03-02 19:36 ` [PATCH v7 5/7] mm: support both pid and pidfd for process_madvise Minchan Kim
2020-03-06 11:14 ` Vlastimil Babka
2020-03-11 0:42 ` Minchan Kim
2020-05-08 18:36 ` Minchan Kim
2020-05-08 23:04 ` Andrew Morton
2020-05-09 12:48 ` Christian Brauner
2020-05-09 23:14 ` Minchan Kim
2020-05-12 19:55 ` Suren Baghdasaryan
2020-03-02 19:36 ` [PATCH v7 6/7] mm/madvise: employ mmget_still_valid for write lock Minchan Kim
2020-03-06 12:52 ` Vlastimil Babka
2020-03-06 13:03 ` Oleksandr Natalenko
2020-03-06 16:03 ` Vlastimil Babka
2020-03-09 12:30 ` Oleksandr Natalenko
2020-03-10 22:28 ` Minchan Kim [this message]
2020-03-02 19:36 ` [PATCH v7 7/7] mm/madvise: allow KSM hints for remote API Minchan Kim
2020-03-06 13:13 ` Vlastimil Babka
2020-03-06 13:41 ` Oleksandr Natalenko
2020-03-06 16:08 ` Vlastimil Babka
2020-03-09 13:11 ` Oleksandr Natalenko
2020-03-09 15:08 ` Michal Hocko
2020-03-09 15:19 ` Oleksandr Natalenko
2020-03-09 15:42 ` Vlastimil Babka
2020-03-09 16:03 ` Michal Hocko
2020-06-11 2:21 ` Jann Horn
2020-03-02 21:16 ` [PATCH v7 0/7] introduce memory hinting API for external process Andrew Morton
2020-03-02 21:42 ` Minchan Kim
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