From: Oleg Nesterov <oleg@redhat.com>
To: Mike Frysinger <vapier.adi@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
Roland McGrath <roland@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-sh@vger.kernel.org, Paul Mundt <lethal@linux-sh.org>,
uclinux-dist-devel@blackfin.uclinux.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage
Date: Wed, 26 May 2010 12:40:06 +0000 [thread overview]
Message-ID: <20100526124006.GA28358@redhat.com> (raw)
In-Reply-To: <AANLkTilT3D8c86LYK2DxcNpM2F3D8iCbgY_sfUg8h58p@mail.gmail.com>
On 05/25, Mike Frysinger wrote:
>
> On Tue, May 25, 2010 at 06:23, Oleg Nesterov wrote:
> > - arch/blackfin/kernel/ptrace.c:is_user_addr_valid()
> > needs mmap_sem around find_vma()
> >
> > The lockless access to mm->context.sram_list doesn't look
> > safe to me.
> >
> > If we add get_task_mm() - this protects us against
> > destroy_context() only. What is the tracee's sub-thread
> > does sys_sram_alloc() or sys_sram_free() in parallel?
>
> i dont believe there are any code paths in UP systems where this would
> be a practical problem because sram_list is only updated by syscalls
> from userspace.
Yes sure, UP && !PREEMPT is safe.
> we probably should add proper locking to this
> structure though.
Agreed. I'll try to make the trivial patch tomorrow. I think we
can just use mm->mmap_sem, is_user_addr_valid() needs this lock
for find_vma() anyway.
Oleg.
WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Mike Frysinger <vapier.adi@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
Roland McGrath <roland@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-sh@vger.kernel.org, Paul Mundt <lethal@linux-sh.org>,
uclinux-dist-devel@blackfin.uclinux.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm
Date: Wed, 26 May 2010 14:40:06 +0200 [thread overview]
Message-ID: <20100526124006.GA28358@redhat.com> (raw)
In-Reply-To: <AANLkTilT3D8c86LYK2DxcNpM2F3D8iCbgY_sfUg8h58p@mail.gmail.com>
On 05/25, Mike Frysinger wrote:
>
> On Tue, May 25, 2010 at 06:23, Oleg Nesterov wrote:
> > - arch/blackfin/kernel/ptrace.c:is_user_addr_valid()
> > needs mmap_sem around find_vma()
> >
> > The lockless access to mm->context.sram_list doesn't look
> > safe to me.
> >
> > If we add get_task_mm() - this protects us against
> > destroy_context() only. What is the tracee's sub-thread
> > does sys_sram_alloc() or sys_sram_free() in parallel?
>
> i dont believe there are any code paths in UP systems where this would
> be a practical problem because sram_list is only updated by syscalls
> from userspace.
Yes sure, UP && !PREEMPT is safe.
> we probably should add proper locking to this
> structure though.
Agreed. I'll try to make the trivial patch tomorrow. I think we
can just use mm->mmap_sem, is_user_addr_valid() needs this lock
for find_vma() anyway.
Oleg.
next prev parent reply other threads:[~2010-05-26 12:40 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-11 9:36 [PATCH] ptrace: unify FDPIC implementations Mike Frysinger
2010-02-11 9:36 ` Mike Frysinger
2010-02-11 20:24 ` Roland McGrath
2010-02-11 20:24 ` Roland McGrath
2010-02-11 21:07 ` David Howells
2010-02-11 23:26 ` Paul Mundt
2010-02-11 23:26 ` Paul Mundt
2010-02-16 0:30 ` Mike Frysinger
2010-02-16 0:30 ` Mike Frysinger
2010-02-16 1:10 ` Paul Mundt
2010-02-16 1:10 ` Paul Mundt
2010-02-16 8:12 ` Mike Frysinger
2010-02-16 8:12 ` Mike Frysinger
2010-05-21 8:42 ` [PATCH v2] " Mike Frysinger
2010-05-21 8:42 ` Mike Frysinger
2010-05-21 16:26 ` Oleg Nesterov
2010-05-21 16:26 ` Oleg Nesterov
2010-05-21 18:35 ` Roland McGrath
2010-05-21 18:35 ` Roland McGrath
2010-05-22 14:54 ` [PATCH -mm 0/1] (Was: ptrace: unify FDPIC implementations) Oleg Nesterov
2010-05-22 16:53 ` Oleg Nesterov
2010-05-22 14:55 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of Oleg Nesterov
2010-05-22 16:54 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Oleg Nesterov
2010-05-24 4:33 ` [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix Mike Frysinger
2010-05-24 4:33 ` [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Mike Frysinger
2010-05-24 8:38 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of Roland McGrath
2010-05-24 8:38 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Roland McGrath
2010-05-24 14:36 ` David Howells
2010-05-24 14:36 ` David Howells
2010-05-24 15:14 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage Oleg Nesterov
2010-05-24 15:14 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Oleg Nesterov
2010-05-24 23:42 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage Roland McGrath
2010-05-24 23:42 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Roland McGrath
2010-05-25 1:29 ` [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix Mike Frysinger
2010-05-25 1:29 ` [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Mike Frysinger
2010-05-25 19:11 ` [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix Roland McGrath
2010-05-25 19:11 ` [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Roland McGrath
2010-05-25 9:14 ` David Howells
2010-05-25 9:14 ` David Howells
2010-05-25 10:23 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage Oleg Nesterov
2010-05-25 10:23 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Oleg Nesterov
2010-05-25 12:24 ` David Howells
2010-05-25 12:24 ` David Howells
2010-05-25 12:30 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage Oleg Nesterov
2010-05-25 12:30 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Oleg Nesterov
2010-05-25 17:28 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of Mike Frysinger
2010-05-25 17:28 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm Mike Frysinger
2010-05-26 12:40 ` Oleg Nesterov [this message]
2010-05-26 12:40 ` Oleg Nesterov
2010-05-27 19:55 ` [PATCH 0/2] blackfin: ptrace mm/sram_list fixes Oleg Nesterov
2010-05-27 19:55 ` Oleg Nesterov
2010-05-27 19:56 ` [PATCH 1/2] blackfin: ptrace: fix the unsafe usage of mm/find_vma Oleg Nesterov
2010-05-27 19:56 ` [PATCH 1/2] blackfin: ptrace: fix the unsafe usage of mm/find_vma in is_user_addr_valid() Oleg Nesterov
2010-05-27 19:56 ` [PATCH 2/2] blackfin: use ->mmap_sem to protect Oleg Nesterov
2010-05-27 19:56 ` [PATCH 2/2] blackfin: use ->mmap_sem to protect mm_context_t->sram_list Oleg Nesterov
2010-05-27 20:21 ` [PATCH 0/2] blackfin: ptrace mm/sram_list fixes Mike Frysinger
2010-05-27 20:21 ` Mike Frysinger
2010-05-28 19:43 ` Oleg Nesterov
2010-05-28 19:43 ` Oleg Nesterov
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