From: Duoming Zhou duoming@zju.edu.cn
[ Upstream commit 7b7dfe4833c70a11cdfa51b38705103bd31eddaa ]
The function gsm_dlci_t1() is a timer handler that runs in an atomic context, but it calls "kzalloc(..., GFP_KERNEL)" that may sleep. As a result, the sleep-in-atomic-context bug will happen. The process is shown below:
gsm_dlci_t1() gsm_dlci_open() gsm_modem_update() gsm_modem_upd_via_msc() gsm_control_send() kzalloc(sizeof(.., GFP_KERNEL) //may sleep
This patch changes the gfp_t parameter of kzalloc() from GFP_KERNEL to GFP_ATOMIC in order to mitigate the bug.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Duoming Zhou duoming@zju.edu.cn Link: https://lore.kernel.org/r/20221002040709.27849-1-duoming@zju.edu.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 154697be11b0..813a45887171 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1577,7 +1577,7 @@ static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, unsigned int command, u8 *data, int clen) { struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), - GFP_KERNEL); + GFP_ATOMIC); unsigned long flags; if (ctrl == NULL) return NULL;