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Groups > linux.kernel > #1653797 > unrolled thread

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

Started byJia-Ju Bai <baijiaju1990@163.com>
First post2017-05-31 05:20 +0200
Last post2017-05-31 13:00 +0200
Articles 2 — 2 participants

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  [PATCH] gadget: Fix a sleep-in-atomic bug Jia-Ju Bai <baijiaju1990@163.com> - 2017-05-31 05:20 +0200
    Re: [PATCH] gadget: Fix a sleep-in-atomic bug Michal Nazarewicz <mina86@mina86.com> - 2017-05-31 13:00 +0200

#1653797 — [PATCH] gadget: Fix a sleep-in-atomic bug

FromJia-Ju Bai <baijiaju1990@163.com>
Date2017-05-31 05:20 +0200
Subject[PATCH] gadget: Fix a sleep-in-atomic bug
Message-ID<tN2kV-7Hn-1@gated-at.bofh.it>
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@163.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

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#1654120

FromMichal Nazarewicz <mina86@mina86.com>
Date2017-05-31 13:00 +0200
Message-ID<tN9w6-3Ek-7@gated-at.bofh.it>
In reply to#1653797
On Wed, May 31 2017, Jia-Ju Bai wrote:
> 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@163.com>

Acked-by: Michal Nazarewicz <mina86@mina86.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;

-- 
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»

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