lkml.org 
[lkml]   [2013]   [May]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] [media] wl128x: do not call copy_to_user() while holding spinlocks
Date
copy_to_user() must not be called with spinlocks held, but it is in
fmc_transfer_rds_from_internal_buff().
The patch copies data to tmpbuf, releases spinlock and then passes it to userspace.

By the way there is a small unification: replace a couple of hardcoded constants by a macro.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
drivers/media/radio/wl128x/fmdrv_common.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/media/radio/wl128x/fmdrv_common.c b/drivers/media/radio/wl128x/fmdrv_common.c
index a002234..253f307 100644
--- a/drivers/media/radio/wl128x/fmdrv_common.c
+++ b/drivers/media/radio/wl128x/fmdrv_common.c
@@ -715,7 +715,7 @@ static void fm_irq_handle_rdsdata_getcmd_resp(struct fmdev *fmdev)
struct fm_rdsdata_format rds_fmt;
struct fm_rds *rds = &fmdev->rx.rds;
unsigned long group_idx, flags;
- u8 *rds_data, meta_data, tmpbuf[3];
+ u8 *rds_data, meta_data, tmpbuf[FM_RDS_BLK_SIZE];
u8 type, blk_idx;
u16 cur_picode;
u32 rds_len;
@@ -1073,6 +1073,7 @@ int fmc_transfer_rds_from_internal_buff(struct fmdev *fmdev, struct file *file,
u8 __user *buf, size_t count)
{
u32 block_count;
+ u8 tmpbuf[FM_RDS_BLK_SIZE];
unsigned long flags;
int ret;

@@ -1087,29 +1088,32 @@ int fmc_transfer_rds_from_internal_buff(struct fmdev *fmdev, struct file *file,
}

/* Calculate block count from byte count */
- count /= 3;
+ count /= FM_RDS_BLK_SIZE;
block_count = 0;
ret = 0;

- spin_lock_irqsave(&fmdev->rds_buff_lock, flags);
-
while (block_count < count) {
- if (fmdev->rx.rds.wr_idx == fmdev->rx.rds.rd_idx)
- break;
+ spin_lock_irqsave(&fmdev->rds_buff_lock, flags);

- if (copy_to_user(buf, &fmdev->rx.rds.buff[fmdev->rx.rds.rd_idx],
- FM_RDS_BLK_SIZE))
+ if (fmdev->rx.rds.wr_idx == fmdev->rx.rds.rd_idx) {
+ spin_unlock_irqrestore(&fmdev->rds_buff_lock, flags);
break;
-
+ }
+ memcpy(tmpbuf, &fmdev->rx.rds.buff[fmdev->rx.rds.rd_idx],
+ FM_RDS_BLK_SIZE);
fmdev->rx.rds.rd_idx += FM_RDS_BLK_SIZE;
if (fmdev->rx.rds.rd_idx >= fmdev->rx.rds.buf_size)
fmdev->rx.rds.rd_idx = 0;

+ spin_unlock_irqrestore(&fmdev->rds_buff_lock, flags);
+
+ if (copy_to_user(buf, tmpbuf, FM_RDS_BLK_SIZE))
+ break;
+
block_count++;
buf += FM_RDS_BLK_SIZE;
ret += FM_RDS_BLK_SIZE;
}
- spin_unlock_irqrestore(&fmdev->rds_buff_lock, flags);
return ret;
}

--
1.7.9.5


\
 
 \ /
  Last update: 2013-05-08 00:41    [W:1.549 / U:0.404 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site