On Sun, 21 Oct 2012 09:52:59 -0200 Thadeu Lima de Souza Cascardo <[email protected]> wrote:
> A gen_pool_chunk uses a bitmap to find what addresses ranges it has > allocated and bugs when we destroy the pool and a chunk has some bits > set. > > There is a problem when it allocates the bitmap. It allocates only the > number of bytes needed for the bits that represent the size it's > allocating. That is, if it needs 16 bits, it will allocate only 2 bytes, > if it needs 31 bits, it will allocate 4 bytes. > > However, the bitops functions uses long types. And when the gen_pool_add > allocates a bitmap, it only clears the bytes it has allocated. So, it's > possible that we have a long word with the contents 0xffffffffffffffff, > and only the first (most significant) bytes are cleared by memset. > However, the destroy function is going to test for the least significant > bits, which will not be clear as expected. > When fixing a bug, please do fully describe that bug. The oops trace would be nice, but can be avoided if a suitable description is included. Does the BUG() happen in gen_pool_destroy(), or in gen_pool_free()? In either case, from your description it sound like the function which is going BUG() is the site which needs fixing because it is checking for non-zero bits outside the correct range? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
