NFC: nci: fix sleep in atomic context bugs caused by nci_skb_alloc
[ Upstream commit 23dd4581350d4ffa23d58976ec46408f8f4c1e16 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2 files changed