Messages in this thread | | | Date | Wed, 24 Aug 2022 10:45:21 -0700 | Subject | Re: [PATCH v2] dmaengine: idxd: avoid deadlock in process_misc_interrupts() | From | Dave Jiang <> |
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On 8/23/2022 5:54 PM, Jerry Snitselaar wrote: > On Tue, Aug 23, 2022 at 09:46:19AM -0700, Dave Jiang wrote: >> On 8/23/2022 9:37 AM, Jerry Snitselaar wrote: >>> idxd_device_clear_state() now grabs the idxd->dev_lock >>> itself, so don't grab the lock prior to calling it. >>> >>> This was seen in testing after dmar fault occurred on system, >>> resulting in lockup stack traces. >>> >>> Cc: Fenghua Yu <fenghua.yu@intel.com> >>> Cc: Dave Jiang <dave.jiang@intel.com> >>> Cc: Vinod Koul <vkoul@kernel.org> >>> Cc: dmaengine@vger.kernel.org >>> Fixes: cf4ac3fef338 ("dmaengine: idxd: fix lockdep warning on device driver removal") >>> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com> >> Thanks Jerry! >> >> Reviewed-by: Dave Jiang <dave.jiang@intel.com> >> > I noticed another problem while looking at this. When the device ends > up in the halted state, and needs an flr or system reset, it calls > idxd_wqs_unmap_portal(). Then if you do a modprobe -r idxd, you hit > the WARN_ON in devm_iounmap(), because the remove code path calls > idxd_wq_portal_unmap(), and wq->portal is null. I'm not sure if it > just needs a simple sanity check in drv_disable_wq() to avoid the call > in the case that it has already been unmapped, or if more cleanup > needs to be done, and possibly a state to differentiate between > halted + soft reset possible, versus halted + flr or system reset > needed. You get multiple "Device is HALTED" messages during the > removal as well.
Thanks!
Fenghua, can you please take a look at this when you have a chance? Thank you!
> > Regards, > Jerry >
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