From: Duoming Zhou <duoming@zju.edu.cn>
To: linux-kernel@vger.kernel.org
Cc: gregkh@linuxfoundation.org, jirislaby@kernel.org,
Duoming Zhou <duoming@zju.edu.cn>
Subject: [PATCH] tty: n_gsm: fix sleep-in-atomic-context bug in gsm_control_send
Date: Sun, 2 Oct 2022 12:07:09 +0800 [thread overview]
Message-ID: <20221002040709.27849-1-duoming@zju.edu.cn> (raw)
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>
---
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 01c112e2e21..2a0de70e0be 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -1670,7 +1670,7 @@ 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;
--
2.17.1
reply other threads:[~2022-10-02 4:07 UTC|newest]
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