Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755634AbYFPQX7 (ORCPT ); Mon, 16 Jun 2008 12:23:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754187AbYFPQXw (ORCPT ); Mon, 16 Jun 2008 12:23:52 -0400 Received: from x346.tv-sign.ru ([89.108.83.215]:55770 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754186AbYFPQXv (ORCPT ); Mon, 16 Jun 2008 12:23:51 -0400 Date: Mon, 16 Jun 2008 20:26:03 +0400 From: Oleg Nesterov To: Andrew Morton Cc: Roland McGrath , linux-kernel@vger.kernel.org Subject: [PATCH] coredump: elf_core_dump: skip kernel threads Message-ID: <20080616162603.GA21028@tv-sign.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2005 Lines: 54 linux_binfmt->core_dump() runs before the process does exit_aio(), this means that we can hit the kernel thread which shares the same ->mm. Afaics, nothing really bad can happen, but perhaps it makes sense to fix this minor bug. It is sad we have to iterate over all threads in system and use GFP_ATOMIC. Hopefully we can kill theses ugly do_each_thread()s, but this needs some nontrivial changes in mm_struct and do_coredump. Signed-off-by: Oleg Nesterov binfmt_elf.c | 6 ++++++ binfmt_elf_fdpic.c | 3 +++ 2 files changed, 9 insertions(+) --- 26-rc2/fs/binfmt_elf.c~CD_SKIP_KTHREAD 2008-06-02 20:46:54.000000000 +0400 +++ 26-rc2/fs/binfmt_elf.c 2008-06-16 20:00:00.000000000 +0400 @@ -1522,6 +1522,9 @@ static int fill_note_info(struct elfhdr rcu_read_lock(); do_each_thread(g, p) if (p->mm == dump_task->mm) { + if (p->flags & PF_KTHREAD) + continue; + t = kzalloc(offsetof(struct elf_thread_core_info, notes[info->thread_notes]), GFP_ATOMIC); @@ -1726,6 +1729,9 @@ static int fill_note_info(struct elfhdr rcu_read_lock(); do_each_thread(g, p) if (current->mm == p->mm && current != p) { + if (p->flags & PF_KTHREAD) + continue; + ets = kzalloc(sizeof(*ets), GFP_ATOMIC); if (!ets) { rcu_read_unlock(); --- 26-rc2/fs/binfmt_elf_fdpic.c~CD_SKIP_KTHREAD 2008-06-02 20:46:54.000000000 +0400 +++ 26-rc2/fs/binfmt_elf_fdpic.c 2008-06-16 18:57:46.000000000 +0400 @@ -1626,6 +1626,9 @@ static int elf_fdpic_core_dump(long sign rcu_read_lock(); do_each_thread(g,p) if (current->mm == p->mm && current != p) { + if (p->flags & PF_KTHREAD) + continue; + tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC); if (!tmp) { rcu_read_unlock(); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/