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authorDuoming Zhou <duoming@zju.edu.cn>2022-05-17 04:25:30 +0300
committerJakub Kicinski <kuba@kernel.org>2022-05-18 03:55:53 +0300
commit23dd4581350d4ffa23d58976ec46408f8f4c1e16 (patch)
tree7a5c5ce71ec4c15d5e35d434cb55004059076a33 /net
parent5361448e45fac6fb96738df748229432a62d78b6 (diff)
downloadlinux-23dd4581350d4ffa23d58976ec46408f8f4c1e16.tar.xz
NFC: nci: fix sleep in atomic context bugs caused by nci_skb_alloc
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> 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>
Diffstat (limited to 'net')
-rw-r--r--net/nfc/nci/data.c2
-rw-r--r--net/nfc/nci/hci.c4
2 files changed, 3 insertions, 3 deletions
diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c
index 6055dc9a82aa..aa5e712adf07 100644
--- a/net/nfc/nci/data.c
+++ b/net/nfc/nci/data.c
@@ -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;
diff --git a/net/nfc/nci/hci.c b/net/nfc/nci/hci.c
index 19703a649b5a..78c4b6addf15 100644
--- a/net/nfc/nci/hci.c
+++ b/net/nfc/nci/hci.c
@@ -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;