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NFC: nci: fix sleep in atomic context bugs caused by nci_skb_alloc

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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: ed06aeefda ("nfc: st-nci: Rename st21nfcb to st-nci")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220517012530.75714-1-duoming@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Duoming Zhou 2022-05-17 09:25:30 +08:00 committed by Jakub Kicinski
parent 5361448e45
commit 23dd458135
2 changed files with 3 additions and 3 deletions
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2
net/nfc/nci/data.c
View File

@ -118,7 +118,7 @@ static int nci_queue_tx_data_frags(struct nci_dev *ndev,
skb_frag = nci_skb_alloc(ndev,
(NCI_DATA_HDR_SIZE + frag_len),
GFP_KERNEL);
GFP_ATOMIC);
if (skb_frag == NULL) {
rc = -ENOMEM;
goto free_exit;

4
net/nfc/nci/hci.c
View File

@ -153,7 +153,7 @@ static int nci_hci_send_data(struct nci_dev *ndev, u8 pipe,
i = 0;
skb = nci_skb_alloc(ndev, conn_info->max_pkt_payload_len +
NCI_DATA_HDR_SIZE, GFP_KERNEL);
NCI_DATA_HDR_SIZE, GFP_ATOMIC);
if (!skb)
return -ENOMEM;
@ -184,7 +184,7 @@ static int nci_hci_send_data(struct nci_dev *ndev, u8 pipe,
if (i < data_len) {
skb = nci_skb_alloc(ndev,
conn_info->max_pkt_payload_len +
NCI_DATA_HDR_SIZE, GFP_KERNEL);
NCI_DATA_HDR_SIZE, GFP_ATOMIC);
if (!skb)
return -ENOMEM;