linux-kernel - [PATCH] gadget: Fix a sleep-in-atomic bug

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Message-Id: <1496200423-3251-1-git-send-email-baijiaju1990@163.com>
Date:   Wed, 31 May 2017 11:13:42 +0800
From:   Jia-Ju Bai <baijiaju1990@....com>
To:     balbi@...nel.org, gregkh@...uxfoundation.org, mina86@...a86.com,
        plr.vincent@...il.com, felixhaedicke@....de, jilin@...dia.com,
        dan.carpenter@...cle.com
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@....com>
Subject: [PATCH] gadget: Fix a sleep-in-atomic bug

The driver may sleep under a spin lock, and the function call path is:
ffs_epfile_io (acquire the lock by spin_lock_irq)
  usb_ep_alloc_request(GFP_KERNEL) --> may sleep

To fix it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".

Signed-off-by: Jia-Ju Bai <baijiaju1990@....com>
---
 drivers/usb/gadget/function/f_fs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 47dda34..be90e25 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1015,7 +1015,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 		else
 			ret = ep->status;
 		goto error_mutex;
-	} else if (!(req = usb_ep_alloc_request(ep->ep, GFP_KERNEL))) {
+	} else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
 		ret = -ENOMEM;
 	} else {
 		req->buf      = data;
-- 
1.7.9.5