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Tejun Heo authored
Most functions in idr fail to deal with the high bits when the idr tree grows to the maximum height. * idr_get_empty_slot() stops growing idr tree once the depth reaches MAX_IDR_LEVEL - 1, which is one depth shallower than necessary to cover the whole range. The function doesn't even notice that it didn't grow the tree enough and ends up allocating the wrong ID given sufficiently high @starting_id. For example, on 64 bit, if the starting id is 0x7fffff01, idr_get_empty_slot() will grow the tree 5 layer deep, which only covers the 30 bits and then proceed to allocate as if the bit 30 wasn't specified. It ends up allocating 0x3fffff01 without the bit 30 but still returns 0x7fffff01. * __idr_remove_all() will not remove anything if the tree is fully grown. * idr_find() can't find anything if the tree is fully grown. * idr_for_each() and idr_get_next() can't iterate anything if the tree is fully grown. Fix it by introducing idr_max() which returns the maximum possible ID given the depth of tree and replacing the id limit checks in all affected places. As the idr_layer pointer array pa[] needs to be 1 larger than the maximum depth, enlarge pa[] arrays by one. While this plugs the discovered issues, the whole code base is horrible and in desparate need of rewrite. It's fragile like hell, Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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