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authorDuoming Zhou <duoming@zju.edu.cn>2022-05-04 13:58:47 +0800
committerPaolo Abeni <pabeni@redhat.com>2022-05-05 10:18:15 +0200
commit4071bf121d59944d5cd2238de0642f3d7995a997 (patch)
tree5a599ce347e5a6c4f6f3ff6b371f139d8262c3f9 /net
parent5a7c5f70c743c6cf32b44b05bd6b19d4ad82f49d (diff)
NFC: netlink: fix sleep in atomic bug when firmware download timeout
There are sleep in atomic bug that could cause kernel panic during firmware download process. The root cause is that nlmsg_new with GFP_KERNEL parameter is called in fw_dnld_timeout which is a timer handler. The call trace is shown below: BUG: sleeping function called from invalid context at include/linux/sched/mm.h:265 Call Trace: kmem_cache_alloc_node __alloc_skb nfc_genl_fw_download_done call_timer_fn __run_timers.part.0 run_timer_softirq __do_softirq ... The nlmsg_new with GFP_KERNEL parameter may sleep during memory allocation process, and the timer handler is run as the result of a "software interrupt" that should not call any other function that could sleep. This patch changes allocation mode of netlink message from GFP_KERNEL to GFP_ATOMIC in order to prevent sleep in atomic bug. The GFP_ATOMIC flag makes memory allocation operation could be used in atomic context. Fixes: 9674da8759df ("NFC: Add firmware upload netlink command") Fixes: 9ea7187c53f6 ("NFC: netlink: Rename CMD_FW_UPLOAD to CMD_FW_DOWNLOAD") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20220504055847.38026-1-duoming@zju.edu.cn Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
-rw-r--r--net/nfc/netlink.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index f184b0db79d4..7c62417ccfd7 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -1244,7 +1244,7 @@ int nfc_genl_fw_download_done(struct nfc_dev *dev, const char *firmware_name,
struct sk_buff *msg;
void *hdr;
- msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
if (!msg)
return -ENOMEM;
@@ -1260,7 +1260,7 @@ int nfc_genl_fw_download_done(struct nfc_dev *dev, const char *firmware_name,
genlmsg_end(msg, hdr);
- genlmsg_multicast(&nfc_genl_family, msg, 0, 0, GFP_KERNEL);
+ genlmsg_multicast(&nfc_genl_family, msg, 0, 0, GFP_ATOMIC);
return 0;