Re: [PATCH 6.6.y] dmaengine: idxd: Fix leaking event log memory

[Wenshan Lan]

On 5/9/2026 10:08 AM, Sasha Levin wrote:
> On Thu, May 07, 2026 at 12:04:15PM +0800, Wenshan Lan wrote:
> > From: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
> >
> > [ Upstream commit ee66bc29578391c9b48523dc9119af67bd5c7c0f ]
> >
> > -	gencfg.bits = ioread32(idxd->reg_base + IDXD_GENCFG_OFFSET);
> > -	if (!gencfg.evl_en)
> > -		return;
> > -
> >   	mutex_lock(&evl->lock);
> This drops the only thing that protects no-evl-capable hardware
> (idxd->evl == NULL) from dereferencing evl in idxd_device_evl_free().
> On 6.6, idxd_init_evl() returns 0 without allocating evl when
> hw.gen_cap.evl_support == 0, and idxd_device_evl_free() is still
> reachable in that path, so taking ee66bc29 alone will introduce a
> NULL deref on hardware without event-log support.
>
> The required prerequisite is upstream commit 52d2edea0d63c
> ("dmaengine: idxd: Fix crash when the event log is disabled"), which
> adds the "if (!evl) return;" guard at the top of idxd_device_evl_free().
> It landed as patch 2 of the same v3 series and is missing from 6.6.y.
>
> Could you resend as a 2-patch series with 52d2edea0d63c as the
> prerequisite? Then I'm happy to queue both for 6.6.y.

Thank you for your review. I will resend v2.

Wenshan Lan

> --
> Thanks,
> Sasha