From: Duoming Zhou duoming@zju.edu.cn
commit 4071bf121d59944d5cd2238de0642f3d7995a997 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/nfc/netlink.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/nfc/netlink.c +++ b/net/nfc/netlink.c @@ -1252,7 +1252,7 @@ int nfc_genl_fw_download_done(struct nfc 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;
@@ -1268,7 +1268,7 @@ int nfc_genl_fw_download_done(struct nfc
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;