From 23dd4581350d4ffa23d58976ec46408f8f4c1e16 Mon Sep 17 00:00:00 2001
From: Duoming Zhou <duoming@zju.edu.cn>
Date: Tue, 17 May 2022 09:25:30 +0800
Subject: [PATCH] NFC: nci: fix sleep in atomic context bugs caused by nci_skb_alloc
Git-commit: 23dd4581350d4ffa23d58976ec46408f8f4c1e16
Patch-mainline: v5.18
References: git-fixes
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
net/nfc/nci/data.c | 2 +-
net/nfc/nci/hci.c | 4 ++--
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;
--
2.35.3