From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Anton Arapov <anton@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] uprobes: document uprobe_register() vs uprobe_mmap() race
Date: Mon, 04 Jun 2012 17:00:48 +0200 [thread overview]
Message-ID: <1338822048.28282.59.camel@twins> (raw)
In-Reply-To: <20120604145331.GC6416@redhat.com>
On Mon, 2012-06-04 at 16:53 +0200, Oleg Nesterov wrote:
I didn't check if its my error or not, however:
> @@ -850,6 +869,10 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
>
> if (is_register) {
> err = install_breakpoint(uprobe, mm, vma, info->vaddr);
> + /*
> + * We can race against uprobe_register(), see the
that should be uprobe_mmap(), since this is the register path ;-)
> + * comment near uprobe_hash().
> + */
> if (err == -EEXIST)
> err = 0;
> } else {
> @@ -1058,8 +1081,10 @@ int uprobe_mmap(struct vm_area_struct *vma)
> }
>
> ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
> -
> - /* Ignore double add: */
> + /*
> + * We can race against uprobe_register(), see the
> + * comment near uprobe_hash().
> + */
> if (ret == -EEXIST) {
> ret = 0;
>
next prev parent reply other threads:[~2012-06-04 15:01 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-04 14:52 [PATCH 0/3] uprobes: make register/unregister O(n) Oleg Nesterov
2012-06-04 14:53 ` [PATCH 1/3] uprobes: rework register_for_each_vma() to make it O(n) Oleg Nesterov
2012-06-04 14:53 ` [PATCH 2/3] uprobes: change build_map_info() to try kmalloc(GFP_NOWAIT) first Oleg Nesterov
2012-06-04 14:59 ` Peter Zijlstra
2012-06-05 10:10 ` Oleg Nesterov
2012-06-04 14:53 ` [PATCH 3/3] uprobes: document uprobe_register() vs uprobe_mmap() race Oleg Nesterov
2012-06-04 15:00 ` Peter Zijlstra [this message]
2012-06-04 15:40 ` Oleg Nesterov
2012-06-04 14:57 ` [PATCH 0/3] uprobes: make register/unregister O(n) Peter Zijlstra
2012-06-04 17:37 ` Srikar Dronamraju
2012-06-04 18:41 ` Oleg Nesterov
2012-06-05 9:28 ` Srikar Dronamraju
2012-06-06 14:49 ` [PATCH v2 " Oleg Nesterov
2012-06-06 14:49 ` [PATCH v2 1/3] uprobes: rework register_for_each_vma() to make it O(n) Oleg Nesterov
2012-06-06 14:50 ` [PATCH v2 2/3] uprobes: change build_map_info() to try kmalloc(GFP_NOWAIT) first Oleg Nesterov
2012-06-06 14:50 ` [PATCH v2 3/3] uprobes: document uprobe_register() vs uprobe_mmap() race Oleg Nesterov
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