On Sun, Sep 21, 2014 at 02:01:21AM +0100, Dimitri John Ledkov wrote: > From: Shawn Landen <shawnlandden@xxxxxxxxx> > > Bug-Debian: http://bugs.debian.org/656955 The bug seems old (2012) and agains 0.19. We've fixed a few unaligned access bugs in the meantime. Can you please retest with 3.16? > --- a/ctree.h > +++ b/ctree.h > @@ -19,6 +19,8 @@ > #ifndef __BTRFS__ > #define __BTRFS__ > > +#include <stdint.h> > + > #if BTRFS_FLAT_INCLUDES > #include "list.h" > #include "kerncompat.h" > @@ -1191,13 +1193,17 @@ struct btrfs_root { > static inline u##bits btrfs_##name(const struct extent_buffer *eb) \ > { \ > const struct btrfs_header *h = (struct btrfs_header *)eb->data; \ > - return le##bits##_to_cpu(h->member); \ > + uint##bits##_t t; \ > + memcpy(&t, &h->member, sizeof(h->member)); \ > + return le##bits##_to_cpu(t); \ The change to memcpy is safe, the compiler is smart enough to not emit any memcpy call for x86_64 and there's no change to the leXX_to_cpu macros. However, I'd like to check first if this is really necessary due to the old version in the bugreport. I'd prefer using the u8/.../u64 types instead of the stdint.h ones, for sake of consistency with the rest of the codebase. > --- a/volumes.c > +++ b/volumes.c > @@ -472,10 +472,11 @@ static int find_next_chunk(struct btrfs_root *root, u64 objectid, u64 *offset) > if (found_key.objectid != objectid) > *offset = 0; > else { > + u64 t; > chunk = btrfs_item_ptr(path->nodes[0], path->slots[0], > struct btrfs_chunk); > - *offset = found_key.offset + > - btrfs_chunk_length(path->nodes[0], chunk); > + t = found_key.offset + btrfs_chunk_length(path->nodes[0], chunk); > + memcpy(offset, &t, sizeof(found_key.offset)); That's not enough, there are more direct assignments to *offset in that function. The preferred way is to add 'put_unaligned' helper into kerncompat.h and use it. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
