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authorLinus Torvalds <torvalds@linux-foundation.org>2008-06-09 10:06:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-06-09 10:06:24 -0700
commitd5791d13b1d45542895104edf4b09476d5ad24b0 (patch)
tree3e3557240717a100dcb63316b4d0c1697e943320 /block
parentf751aa125d1843ea4a9a264b451fd5b1639fab20 (diff)
Fix invalid access errors in blk_lookup_devt
Commit 30f2f0eb4bd2c43d10a8b0d872c6e5ad8f31c9a0 ("block: do_mounts - accept root=<non-existant partition>") extended blk_lookup_devt() to be able to look up partitions that had not yet been registered, but in the process made the assumption that the '&block_class.devices' list only contains disk devices and that you can do 'dev_to_disk(dev)' on them. That isn't actually true. The block_class device list also contains the partitions we've discovered so far, and you can't just do a 'dev_to_disk()' on those. So make sure to only work on devices that block/genhd.c has registered itself, something we can test by checking the 'dev->type' member. This makes the loop in blk_lookup_devt() match the other such loops in this file. [ We may want to do an alternate version that knows to handle _either_ whole-disk devices or partitions, but for now this is the minimal fix for a series of crashes reported by Mariusz Kozlowski in http://lkml.org/lkml/2008/5/25/25 and Ingo in http://lkml.org/lkml/2008/6/9/39 ] Reported-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Reported-by: Ingo Molnar <mingo@elte.hu> Cc: Neil Brown <neilb@suse.de> Cc: Joao Luis Meloni Assirati <assirati@nonada.if.usp.br> Acked-by: Kay Sievers <kay.sievers@vrfy.org> Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'block')
-rw-r--r--block/genhd.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 129ad939f9dd..b922d4801c87 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -660,6 +660,8 @@ dev_t blk_lookup_devt(const char *name, int part)
mutex_lock(&block_class_lock);
list_for_each_entry(dev, &block_class.devices, node) {
+ if (dev->type != &disk_type)
+ continue;
if (strcmp(dev->bus_id, name) == 0) {
struct gendisk *disk = dev_to_disk(dev);

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