lkml.org 
[lkml]   [2013]   [Dec]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Date
    Subject[PATCH 3.2 094/185] Staging: zram: Fix access of NULL pointer
    3.2.54-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Rashika Kheria <rashika.kheria@gmail.com>

    commit 46a51c80216cb891f271ad021f59009f34677499 upstream.

    This patch fixes the bug in reset_store caused by accessing NULL pointer.

    The bdev gets its value from bdget_disk() which could fail when memory
    pressure is severe and hence can return NULL because allocation of
    inode in bdget could fail.

    Hence, this patch introduces a check for bdev to prevent reference to a
    NULL pointer in the later part of the code. It also removes unnecessary
    check of bdev for fsync_bdev().

    Acked-by: Jerome Marchand <jmarchan@redhat.com>
    Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
    Acked-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    [bwh: Backported to 3.2: adjust filename]
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    drivers/staging/zram/zram_sysfs.c | 6 ++++--
    1 file changed, 4 insertions(+), 2 deletions(-)

    --- a/drivers/staging/zram/zram_sysfs.c
    +++ b/drivers/staging/zram/zram_sysfs.c
    @@ -95,6 +95,9 @@ static ssize_t reset_store(struct device
    zram = dev_to_zram(dev);
    bdev = bdget_disk(zram->disk, 0);

    + if (!bdev)
    + return -ENOMEM;
    +
    /* Do not reset an active device! */
    if (bdev->bd_holders)
    return -EBUSY;
    @@ -107,8 +110,7 @@ static ssize_t reset_store(struct device
    return -EINVAL;

    /* Make sure all pending I/O is finished */
    - if (bdev)
    - fsync_bdev(bdev);
    + fsync_bdev(bdev);

    down_write(&zram->init_lock);
    if (zram->init_done)


    \
     
     \ /
      Last update: 2013-12-29 04:21    [W:4.277 / U:0.060 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site