linux-arm-msm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Greg KH <gregkh@linuxfoundation.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: hemantk@codeaurora.org, bbhatt@codeaurora.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	loic.poulain@linaro.org, stable@vger.kernel.org,
	Jeffrey Hugo <quic_jhugo@quicinc.com>
Subject: Re: [PATCH 1/8] bus: mhi: core: Validate channel ID when processing command completions
Date: Thu, 24 Jun 2021 16:39:51 +0200	[thread overview]
Message-ID: <YNSZNxMjX/vNvae+@kroah.com> (raw)
In-Reply-To: <20210624143248.GC6108@workstation>

On Thu, Jun 24, 2021 at 08:02:48PM +0530, Manivannan Sadhasivam wrote:
> On Thu, Jun 24, 2021 at 03:50:45PM +0200, Greg KH wrote:
> > On Mon, Jun 21, 2021 at 09:46:09PM +0530, Manivannan Sadhasivam wrote:
> > > From: Bhaumik Bhatt <bbhatt@codeaurora.org>
> > > 
> > > MHI reads the channel ID from the event ring element sent by the
> > > device which can be any value between 0 and 255. In order to
> > > prevent any out of bound accesses, add a check against the maximum
> > > number of channels supported by the controller and those channels
> > > not configured yet so as to skip processing of that event ring
> > > element.
> > > 
> > > Cc: stable@vger.kernel.org
> > > Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device")
> > > Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
> > > Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
> > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
> > > Link: https://lore.kernel.org/r/1619481538-4435-1-git-send-email-bbhatt@codeaurora.org
> > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > ---
> > >  drivers/bus/mhi/core/main.c | 15 ++++++++++-----
> > >  1 file changed, 10 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> > > index 22acde118bc3..ed07421c4870 100644
> > > --- a/drivers/bus/mhi/core/main.c
> > > +++ b/drivers/bus/mhi/core/main.c
> > > @@ -773,11 +773,16 @@ static void mhi_process_cmd_completion(struct mhi_controller *mhi_cntrl,
> > >  	cmd_pkt = mhi_to_virtual(mhi_ring, ptr);
> > >  
> > >  	chan = MHI_TRE_GET_CMD_CHID(cmd_pkt);
> > > -	mhi_chan = &mhi_cntrl->mhi_chan[chan];
> > > -	write_lock_bh(&mhi_chan->lock);
> > > -	mhi_chan->ccs = MHI_TRE_GET_EV_CODE(tre);
> > > -	complete(&mhi_chan->completion);
> > > -	write_unlock_bh(&mhi_chan->lock);
> > > +	WARN_ON(chan >= mhi_cntrl->max_chan);
> > 
> > What can ever trigger this WARN_ON()?  Do you mean to reboot a machine
> > if panic-on-warn is set?
> > 
> > If this can actually happen, then check for it and recover properly,
> > don't just blindly warn and then keep on going.
> > 
> 
> We can't do much here other than warning the user and dropping the
> command.

But you didn't warn anyone.  Well, you rebooted the machine, is that ok?
If this can be triggered by a user, this should never happen.

Do not use WARN_ON() ever please.

> There is no recovery possible because, the device has sent the command
> completion event on a wrong channel. It can't happen usually unless a
> malcious device sits on the other end.

Then just eat the message and move on, please do not crash the box.

thanks,

gre k-h

  reply	other threads:[~2021-06-24 14:39 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-21 16:16 [PATCH 0/8] MHI patches for v5.14 Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 1/8] bus: mhi: core: Validate channel ID when processing command completions Manivannan Sadhasivam
2021-06-24 13:50   ` Greg KH
2021-06-24 14:32     ` Manivannan Sadhasivam
2021-06-24 14:39       ` Greg KH [this message]
2021-06-24 14:47         ` Manivannan Sadhasivam
2021-06-24 15:27           ` Greg KH
2021-06-24 15:56             ` Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 2/8] bus: mhi: core: Fix power down latency Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 3/8] bus: mhi: Wait for M2 state during system resume Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 4/8] bus: mhi: Add inbound buffers allocation flag Manivannan Sadhasivam
2021-06-24 13:51   ` Greg KH
2021-06-24 15:39     ` Loic Poulain
2021-06-24 16:48       ` Greg KH
2021-06-24 19:01         ` Loic Poulain
2021-06-21 16:16 ` [PATCH 5/8] bus: mhi: pci-generic: Add missing 'pci_disable_pcie_error_reporting()' calls Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 6/8] bus: mhi: core: Add support for processing priority of event ring Manivannan Sadhasivam
2021-06-24 13:53   ` Greg KH
2021-06-24 14:24     ` Manivannan Sadhasivam
2021-06-24 14:40       ` Greg KH
2021-06-24 14:50         ` Manivannan Sadhasivam
2021-06-21 16:16 ` [PATCH 7/8] bus: mhi: pci_generic: Apply no-op for wake using sideband wake boolean Manivannan Sadhasivam
2021-06-24 13:54   ` Greg KH
2021-06-21 16:16 ` [PATCH 8/8] bus: mhi: pci_generic: Add Cinterion MV31-W PCIe to MHI Manivannan Sadhasivam
2021-06-24 13:54   ` Greg KH
2021-06-24 13:54 ` [PATCH 0/8] MHI patches for v5.14 Greg KH
2021-06-24 14:20   ` Manivannan Sadhasivam

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YNSZNxMjX/vNvae+@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=bbhatt@codeaurora.org \
    --cc=hemantk@codeaurora.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=loic.poulain@linaro.org \
    --cc=manivannan.sadhasivam@linaro.org \
    --cc=quic_jhugo@quicinc.com \
    --cc=stable@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).