tty: n_gsm: fix sleep-in-atomic-context bug in gsm_control_send
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>