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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="F3RP9lbj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A494B1F00A3A; Thu, 6 Aug 2026 13:49:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786024200; bh=mzx55sYR17rtWzeVrQP3jxEurNyMq6DyCUsbSTvjsNg=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=F3RP9lbjtTT1JI2v9v0+1QN6f8U7hKGY+S8TKFWQbufG1I1xaZDWDPQxgFv336Nax 5ttcYUEol5PPolrQefkbg3FysQgHyBNoaCYYNVzw1Z6570rlm5Vc3ESXmT4xs6QOh5 X8m28FzDKB0Ar6bQl85k0M2jeZz0TXWrBmGlt8RDEBByaHTZ0XtYTXCibVOP9Gz+qd sKKK6EDTJfdT2h7Fmy+KIX1ST4xIfFllJM0pznTn86sCRFuWULljEvTfGPlsg/qj/q YjWyXny38KbEiI4WJxNAirEMJqPSNDt91IXRTrZDjoXVeEHSypnLZJGa7yCX3opisY nAztivRsse+/g== From: sashiko-bot@kernel.org Subject: Re: [PATCH V4 09/14] i3c: master: Report wakeup events for IBIs Reply-To: sashiko-reviews@lists.linux.dev To: "Adrian Hunter" Cc: "Alexandre Belloni" , Frank.Li@kernel.org, linux-pci@vger.kernel.org, linux-i3c@lists.infradead.org In-Reply-To: <20260806131857.119830-10-adrian.hunter@intel.com> References: <20260806131857.119830-1-adrian.hunter@intel.com> <20260806131857.119830-10-adrian.hunter@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 06 Aug 2026 13:49:59 +0000 Message-Id: <20260806134959.A494B1F00A3A@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 2 potential issue(= s) to consider: New issues: - [High] NULL pointer dereference in `i3c_master_queue_ibi()` when accessin= g `dev->dev`. Pre-existing issues: - [High] Race condition in `i3c_master_queue_ibi()` leading to Use-After-Fr= ee of `dev->ibi`. -- --- Patch [9]: [PATCH V4 09/14] i3c: master: Report wakeup events for IBIs = --- commit 461a49ac6bedf9467539aa8fac5583bf77ad5045 Author: Adrian Hunter i3c: master: Report wakeup events for IBIs An I3C device configured as a wakeup source can wake the system by generating an In-Band Interrupt (IBI). When an IBI is queued for processing, record a wakeup event for the device if wakeup is enabled. > diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c > index 2616354dbe545..6c53414919445 100644 > --- a/drivers/i3c/master.c > +++ b/drivers/i3c/master.c [ ... ] > @@ -3397,6 +3400,9 @@ void i3c_master_queue_ibi(struct i3c_dev_desc *dev,= struct i3c_ibi_slot *slot) > if (!dev->ibi || !slot) > return; > =20 > + if (device_may_wakeup(&dev->dev->dev)) > + pm_wakeup_event(&dev->dev->dev, I3C_WAKEUP_PROCESSING_TIME_MS); > + [Severity: High] Can dev->dev be NULL here? Looking at i3c_master_unregister_i3c_devs(), it sets i3cdev->dev to NULL during device teardown: drivers/i3c/master.c:i3c_master_unregister_i3c_devs() { ... i3cdev->dev->desc =3D NULL; put_device(&i3cdev->dev->dev); i3cdev->dev =3D NULL; } } If a hardware IBI is received during or shortly after this teardown, wouldn't accessing &dev->dev->dev cause a NULL pointer dereference when evaluated inside device_may_wakeup()? > atomic_inc(&dev->ibi->pending_ibis); [Severity: High] This is a pre-existing issue, but does the lack of synchronization here all= ow a use-after-free of dev->ibi? The teardown path in i3c_dev_disable_ibi_locked() checks pending_ibis locklessly and bypasses waiting if it reads 0: drivers/i3c/master.c:i3c_dev_disable_ibi_locked() { ... if (atomic_read(&dev->ibi->pending_ibis)) wait_for_completion(&dev->ibi->all_ibis_handled); ... } If an ISR is executing concurrently and passes the check for !dev->ibi at the top of i3c_master_queue_ibi(), but hasn't yet reached the atomic_inc() here, the teardown thread could see pending_ibis =3D=3D 0 and proceed to fr= ee dev->ibi in i3c_dev_free_ibi_locked(): drivers/i3c/master.c:i3c_dev_free_ibi_locked() { ... kfree(dev->ibi); dev->ibi =3D NULL; ... } When the ISR resumes, wouldn't the subsequent accesses to dev->ibi->pending_ibis and dev->ibi->wq cause a use-after-free? Adding the wakeup event logic slightly widens this existing race window. > queue_work(dev->ibi->wq, &slot->work); > } --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260806131857.1198= 30-1-adrian.hunter@intel.com?part=3D9