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    Subject[34-longterm 082/179] PM: Free memory bitmaps if opening /dev/snapshot fails
    Date
    From: Michal Kubecek <mkubecek@suse.cz>

    -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
    -------------------

    commit 8440f4b19494467883f8541b7aa28c7bbf6ac92b upstream.

    When opening /dev/snapshot device, snapshot_open() creates memory
    bitmaps which are freed in snapshot_release(). But if any of the
    callbacks called by pm_notifier_call_chain() returns NOTIFY_BAD, open()
    fails, snapshot_release() is never called and bitmaps are not freed.
    Next attempt to open /dev/snapshot then triggers BUG_ON() check in
    create_basic_memory_bitmaps(). This happens e.g. when vmwatchdog module
    is active on s390x.

    Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
    Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
    Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
    ---
    kernel/power/user.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    diff --git a/kernel/power/user.c b/kernel/power/user.c
    index 16a7d95..37b32d5 100644
    --- a/kernel/power/user.c
    +++ b/kernel/power/user.c
    @@ -113,8 +113,10 @@ static int snapshot_open(struct inode *inode, struct file *filp)
    if (error)
    pm_notifier_call_chain(PM_POST_RESTORE);
    }
    - if (error)
    + if (error) {
    + free_basic_memory_bitmaps();
    atomic_inc(&snapshot_device_available);
    + }
    data->frozen = 0;
    data->ready = 0;
    data->platform_support = 0;
    --
    1.7.9.6


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