From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: Noa Osherovich <noaos-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: hch-jcswGhMUV9g@public.gmane.org,
sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org,
linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Majd Dibbiny <majd-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: Poll CQ syncing problem
Date: Wed, 1 Mar 2017 15:51:24 +0100 [thread overview]
Message-ID: <20170301145124.GA12121@lst.de> (raw)
In-Reply-To: <3ba1baab-e2ac-358d-3b3b-ff4a27405c93-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
On Wed, Mar 01, 2017 at 04:30:26PM +0200, Noa Osherovich wrote:
> Analysis:
> Since ib_comp_wq isn't single threaded, two works can run in parallel for the same CQ,
> executing __ib_process_cq.
They shouldn't. Each CQ has a single work_struct, and any given work_struct
should only be executing at once:
"Note that the flag ``WQ_NON_REENTRANT`` no longer exists as all
workqueues are now non-reentrant - any work item is guaranteed to be
executed by at most one worker system-wide at any given time."
> Since this function isn't thread safe and the wc array is shared, it causes a data corruption
> which eventually crashes in the MAD layer due to a double list_del of the same element.
This should not be the case. What kernel version are you testing and does
it contain any patches touching core kernel code?
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next prev parent reply other threads:[~2017-03-01 14:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <b4355d22-fc79-c860-de8a-5a4d468c884d@mellanox.com>
[not found] ` <b4355d22-fc79-c860-de8a-5a4d468c884d-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2017-03-01 14:30 ` Poll CQ syncing problem Noa Osherovich
[not found] ` <3ba1baab-e2ac-358d-3b3b-ff4a27405c93-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2017-03-01 14:51 ` Christoph Hellwig [this message]
2017-03-01 15:28 ` Noa Osherovich
2017-03-01 16:44 ` Sagi Grimberg
[not found] ` <0786659a-da12-e8f7-329e-3caa8cc8791f-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
2017-03-01 16:46 ` Sagi Grimberg
2017-03-02 6:04 ` Noa Osherovich
2017-03-01 16:52 ` Bart Van Assche
[not found] ` <1488387143.2699.6.camel-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2017-03-02 5:59 ` Noa Osherovich
[not found] ` <4d8ac8fd-8ef1-6f6b-177c-2c3ab131f99c-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2017-03-02 6:06 ` Bart Van Assche
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