Messages in this thread | | | Subject | Re: Poll CQ syncing problem | From | Noa Osherovich <> | Date | Wed, 1 Mar 2017 17:28:41 +0200 |
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On 3/1/2017 4:51 PM, Christoph Hellwig wrote:
> 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?
Thanks Christoph for the quick response.
Currently we see this only in old kernels. I'll investigate this more and update.
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