From: oleg@redhat.com (Oleg Nesterov)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 5/6] Uprobes/sdt: Prevent multiple reference counter for same uprobe
Date: Fri, 27 Jul 2018 15:55:29 +0200 [thread overview]
Message-ID: <20180727135528.GA3618@redhat.com> (raw)
In-Reply-To: <19d8abb0-44a3-cb26-405d-95f63fc01517@linux.ibm.com>
Hi Ravi,
On 07/27, Ravi Bangoria wrote:
>
> > I simply can't understand this "bool installed"....
>
>
> That boolean is needed because consumer_filter() returns false when this
> function gets called first time from uprobe_register().
Ah yes, I forgot about the (ugly) 2-stage TRACE_REG_PERF_REGISTER +
TRACE_REG_PERF_OPEN logic...
But then I think the whole idea of REF_CTR_OFF_RELOADED is even more broken.
Nevermind.
> I have a solution for this. Idea is, if reference counter is reloaded, save
> of all mms for which consumer_filter() denied to updated when being called
> from register_for_each_vma(). Use this list of mms as checklist next time
> onwards. I don't know if it's good to do that or not.
Sounds horrible ;) and I bet this is not enough.
> Please let me know if you have any better approach.
Just drop this patch.
If we can't make it per consumer, let it be global like it was in first version.
Oleg.
next prev parent reply other threads:[~2018-07-27 13:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-16 8:47 [PATCH v6 0/6] Uprobes: Support SDT markers having reference count (semaphore) Ravi Bangoria
2018-07-16 8:47 ` [PATCH v6 1/6] Uprobes: Simplify uprobe_register() body Ravi Bangoria
2018-07-16 8:47 ` [PATCH v6 2/6] Uprobe: Additional argument arch_uprobe to uprobe_write_opcode() Ravi Bangoria
2018-07-16 8:47 ` [PATCH v6 3/6] Uprobes: Support SDT markers having reference count (semaphore) Ravi Bangoria
2018-07-23 16:26 ` Oleg Nesterov
2018-07-24 3:34 ` Ravi Bangoria
2018-07-27 13:59 ` Oleg Nesterov
2018-07-24 14:21 ` Masami Hiramatsu
2018-07-16 8:47 ` [PATCH v6 4/6] trace_uprobe/sdt: Prevent multiple reference counter for same uprobe Ravi Bangoria
2018-07-16 8:47 ` [PATCH v6 5/6] Uprobes/sdt: " Ravi Bangoria
2018-07-25 11:08 ` Oleg Nesterov
2018-07-27 4:17 ` Ravi Bangoria
2018-07-27 13:55 ` Oleg Nesterov [this message]
2018-07-16 8:47 ` [PATCH v6 6/6] perf probe: Support SDT markers having reference counter (semaphore) Ravi Bangoria
2018-07-20 13:47 ` [PATCH v6 0/6] Uprobes: Support SDT markers having reference count (semaphore) Ravi Bangoria
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