lkml.org 
[lkml]   [2022]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH net v2] NFC: nci: fix sleep in atomic context bugs caused by nci_skb_alloc
Hello,

On Tue, 17 May 2022 08:25:04 +0200 Krzysztof wrote:

> On 17/05/2022 03:25, Duoming Zhou wrote:
> > There are sleep in atomic context bugs when the request to secure
> > element of st-nci is timeout. The root cause is that nci_skb_alloc
> > with GFP_KERNEL parameter is called in st_nci_se_wt_timeout which is
> > a timer handler. The call paths that could trigger bugs are shown below:
> >
> > (interrupt context 1)
> > st_nci_se_wt_timeout
> > nci_hci_send_event
> > nci_hci_send_data
> > nci_skb_alloc(..., GFP_KERNEL) //may sleep
> >
> > (interrupt context 2)
> > st_nci_se_wt_timeout
> > nci_hci_send_event
> > nci_hci_send_data
> > nci_send_data
> > nci_queue_tx_data_frags
> > nci_skb_alloc(..., GFP_KERNEL) //may sleep
> >
> > This patch changes allocation mode of nci_skb_alloc from GFP_KERNEL to
> > GFP_ATOMIC in order to prevent atomic context sleeping. The GFP_ATOMIC
> > flag makes memory allocation operation could be used in atomic context.
> >
> > Fixes: ed06aeefdac3 ("nfc: st-nci: Rename st21nfcb to st-nci")
> > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
> > ---
> > Changes in v2:
> > - Change the Fixes tag to commit st_nci_se_wt_timeout was added.
>
> Please add Acked-by/Reviewed-by tags when posting new versions. However,
> there's no need to repost patches *only* to add the tags. The upstream
> maintainer will do that for acks received on the version they apply.
>
> https://elixir.bootlin.com/linux/v5.13/source/Documentation/process/submitting-patches.rst#L543
>
> If a tag was not added on purpose, please state why and what changed.

Thank you very much, I will read the documentation carefully.
I'm sorry, I forgot the Reviewed-by tag.

> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Duoming Zhou
\
 
 \ /
  Last update: 2022-05-17 08:46    [W:0.303 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site