From: Oleg Nesterov <oleg@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: "David S. Miller" <davem@davemloft.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Cyrill Gorcunov <gorcunov@openvz.org>,
David Howells <dhowells@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Sasha Levin <levinsasha928@gmail.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Alexey Dobriyan <adobriyan@gmail.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH v2 4/7] fs/proc/task_mmu.c: shift mm_access() from m_start() to proc_maps_open()
Date: Wed, 3 Dec 2014 18:34:48 +0100 [thread overview]
Message-ID: <20141203173448.GA4003@redhat.com> (raw)
In-Reply-To: <20141203141433.GA25683@node.dhcp.inet.fi>
On 12/03, Kirill A. Shutemov wrote:
>
> On Tue, Aug 05, 2014 at 09:46:55PM +0200, Oleg Nesterov wrote:
> > A simple test-case from Kirill Shutemov
> >
> > cat /proc/self/maps >/dev/null
> > chmod +x /proc/self/net/packet
> > exec /proc/self/net/packet
> >
> > makes lockdep unhappy, cat/exec take seq_file->lock + cred_guard_mutex in
> > the opposite order.
>
> Oleg, I see it again with almost the same test-case:
>
> cat /proc/self/stack >/dev/null
> chmod +x /proc/self/net/packet
> exec /proc/self/net/packet
Yes, there are more lock_trace/mm_access (ab)users. Fortunately, they
are much simpler than proc/pid/maps (which also asked for other cleanups
and fixes).
I'll try to take a look, thanks for reminding.
And I agree with Eric, chmod+x probably makes no sense. Still I think
this code deserves some cleanups regardless. To the point I think that
lock_trace() should probably die.
Thanks!
Oleg.
next prev parent reply other threads:[~2014-12-03 17:34 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-05 19:46 [PATCH v2 0/7] /proc/PID/*maps* fixes/cleanups Oleg Nesterov
2014-08-05 19:46 ` [PATCH v2 1/7] fs/proc/task_mmu.c: don't use task->mm in m_start() and show_*map() Oleg Nesterov
2014-08-06 9:52 ` Kirill A. Shutemov
2014-08-06 14:10 ` Oleg Nesterov
2014-08-06 19:41 ` Oleg Nesterov
2014-08-05 19:46 ` [PATCH v2 2/7] fs/proc/task_mmu.c: unify/simplify do_maps_open() and numa_maps_open() Oleg Nesterov
2014-08-06 9:55 ` Kirill A. Shutemov
2014-08-05 19:46 ` [PATCH v2 3/7] proc: introduce proc_mem_open() Oleg Nesterov
2014-08-06 9:57 ` Kirill A. Shutemov
2014-08-05 19:46 ` [PATCH v2 4/7] fs/proc/task_mmu.c: shift mm_access() from m_start() to proc_maps_open() Oleg Nesterov
2014-08-06 10:05 ` Kirill A. Shutemov
2014-12-03 14:14 ` Kirill A. Shutemov
2014-12-03 16:59 ` Eric W. Biederman
2014-12-04 16:17 ` Kirill A. Shutemov
2014-12-03 17:34 ` Oleg Nesterov [this message]
2014-08-05 19:46 ` [PATCH v2 5/7] fs/proc/task_mmu.c: simplify the vma_stop() logic Oleg Nesterov
2014-08-06 10:12 ` Kirill A. Shutemov
2014-08-05 19:47 ` [PATCH v2 6/7] fs/proc/task_mmu.c: cleanup the "tail_vma" horror in m_next() Oleg Nesterov
2014-08-06 10:17 ` Kirill A. Shutemov
2014-08-05 19:47 ` [PATCH v2 7/7] fs/proc/task_mmu.c: shift "priv->task = NULL" from m_start() to m_stop() Oleg Nesterov
2014-08-06 10:18 ` Kirill A. Shutemov
2014-08-06 10:19 ` [PATCH v2 0/7] /proc/PID/*maps* fixes/cleanups Kirill A. Shutemov
2014-08-06 18:48 ` Cyrill Gorcunov
2014-08-07 19:17 ` [PATCH 0/5] fs/proc/task_mmu.c: cleanup tail_vma/last_addr mess Oleg Nesterov
2014-08-07 19:17 ` [PATCH 1/5] fs/proc/task_mmu.c: kill the suboptimal and confusing m->version logic Oleg Nesterov
2014-08-07 19:17 ` [PATCH 2/5] fs/proc/task_mmu.c: simplify m_start() to make it readable Oleg Nesterov
2014-08-07 19:17 ` [PATCH 3/5] fs/proc/task_mmu.c: introduce m_next_vma() helper Oleg Nesterov
2014-08-07 19:17 ` [PATCH 4/5] fs/proc/task_mmu.c: reintroduce m->version logic Oleg Nesterov
2014-08-07 19:18 ` [PATCH 5/5] fs/proc/task_mmu.c: update m->version in the main loop in m_start() Oleg Nesterov
2014-08-11 17:00 ` [PATCH 0/3] fs/proc/task_nommu.c: copy-and-paste the changes from task_mmu.c Oleg Nesterov
2014-08-11 17:00 ` [PATCH 1/3] fs/proc/task_nommu.c: change maps_open() to use __seq_open_private() Oleg Nesterov
2014-08-11 17:00 ` [PATCH 2/3] fs/proc/task_nommu.c: shift mm_access() from m_start() to proc_maps_open() Oleg Nesterov
2014-08-11 17:00 ` [PATCH 3/3] fs/proc/task_nommu.c: don't use priv->task->mm Oleg Nesterov
2014-08-12 13:57 ` [PATCH 0/3] fs/proc/task_nommu.c: copy-and-paste the changes from task_mmu.c Greg Ungerer
2014-08-12 17:35 ` Oleg Nesterov
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