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From: Mike Frysinger <vapier.adi@gmail.com>
To: Oleg Nesterov <oleg@redhat.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
Date: Tue, 25 May 2010 17:28:19 +0000	[thread overview]
Message-ID: <AANLkTilT3D8c86LYK2DxcNpM2F3D8iCbgY_sfUg8h58p@mail.gmail.com> (raw)
In-Reply-To: <20100525102345.GA23574@redhat.com>

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.  we probably should add proper locking to this
structure though.  i'll open a tracker item about it, thanks !
-mike

  reply	other threads:[~2010-05-25 17:28 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-11  9:36 [PATCH] ptrace: unify FDPIC implementations Mike Frysinger
2010-02-11 20:24 ` Roland McGrath
2010-02-11 21:07 ` David Howells
2010-02-11 23:26 ` Paul Mundt
2010-02-16  0:30 ` Mike Frysinger
2010-02-16  1:10   ` Paul Mundt
2010-02-16  8:12     ` Mike Frysinger
2010-05-21  8:42   ` [PATCH v2] " Mike Frysinger
2010-05-21 16:26     ` Oleg Nesterov
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 14:55           ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of Oleg Nesterov
2010-05-24  4:33             ` [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix Mike Frysinger
2010-05-24  8:38             ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of Roland McGrath
2010-05-24 14:36           ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm David Howells
2010-05-24 15:14             ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage Oleg Nesterov
2010-05-24 23:42               ` Roland McGrath
2010-05-25  1:29                 ` [Uclinux-dist-devel] [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix Mike Frysinger
2010-05-25 19:11                   ` Roland McGrath
2010-05-25  9:14               ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm David Howells
2010-05-25 10:23                 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage Oleg Nesterov
2010-05-25 17:28                   ` Mike Frysinger [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 19:56                         ` [PATCH 1/2] blackfin: ptrace: fix the unsafe usage of mm/find_vma Oleg Nesterov
2010-05-27 19:56                         ` [PATCH 2/2] blackfin: use ->mmap_sem to protect Oleg Nesterov
2010-05-27 20:21                         ` [PATCH 0/2] blackfin: ptrace mm/sram_list fixes Mike Frysinger
2010-05-28 19:43                           ` Oleg Nesterov
2010-05-25 12:24                 ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm David Howells
2010-05-25 12:30                   ` [PATCH -mm 1/1] ptrace: PTRACE_GETFDPIC: fix the unsafe usage Oleg Nesterov

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