From: Jeff Mahoney <jeffm@xxxxxxxx> The reference counting on dm-mod is zero if no mapped devices are open. This is incorrect, and can lead to an oops if the module is unloaded while mapped devices exist. This patch claims a reference to the module whenever a device is created, and drops it again when the device is freed. Devices must be removed before dm-mod is unloaded. [akpm: too late for 2.6.17 - suitable for 2.6.17.x after it has settled] Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx> Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx> --- drivers/md/dm.c | 6 ++++++ 1 file changed, 6 insertions(+) --- linux-2.6.17.11.orig/drivers/md/dm.c +++ linux-2.6.17.11/drivers/md/dm.c @@ -852,6 +852,9 @@ static struct mapped_device *alloc_dev(u return NULL; } + if (!try_module_get(THIS_MODULE)) + goto bad0; + /* get a minor number for the dev */ r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor); if (r < 0) @@ -918,6 +921,8 @@ static struct mapped_device *alloc_dev(u blk_cleanup_queue(md->queue); free_minor(minor); bad1: + module_put(THIS_MODULE); + bad0: kfree(md); return NULL; } @@ -941,6 +946,7 @@ static void free_dev(struct mapped_devic put_disk(md->disk); blk_cleanup_queue(md->queue); + module_put(THIS_MODULE); kfree(md); } --WIyZ46R2i8wDzkSu Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="dm-mirror-sector-offset-fix.patch" -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
