The patch titled
dm: add module ref counting
has been added to the -mm tree. Its filename is
dm-add-module-ref-counting.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: dm: add module ref counting
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>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/md/dm.c | 6 ++++++
1 files changed, 6 insertions(+)
diff -puN drivers/md/dm.c~dm-add-module-ref-counting drivers/md/dm.c
--- devel/drivers/md/dm.c~dm-add-module-ref-counting 2006-05-25 15:15:32.000000000 -0700
+++ devel-akpm/drivers/md/dm.c 2006-05-25 15:15:32.000000000 -0700
@@ -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);
}
_
Patches currently in -mm which might be from jeffm@xxxxxxxx are
lib-add-idr_replace.patch
lib-add-idr_replace-tidy.patch
dm-fix-idr-minor-allocation.patch
dm-move-idr_pre_get.patch
dm-change-minor_lock-to-spinlock.patch
dm-add-dmf_freeing.patch
dm-fix-mapped-device-ref-counting.patch
dm-add-module-ref-counting.patch
dm-fix-block-device-initialisation.patch
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