Messages in this thread | | | Date | Tue, 21 Jan 2014 10:36:19 +0000 | From | James Hogan <> | Subject | Re: [PATCH] drivers: staging: lustre: lustre: include: add "__attribute__((packed))" for the related union |
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Hi Dan,
On 20/01/14 21:13, Dan Carpenter wrote: > I made a quick and dirty sparse patch to check for this. I don't think > I will bother trying to send it to sparse upstream, but you can if you > want to. > > It found 289 unions which might need a __packed added. The lustre > unions were not in my allmodconfig so they're not listed.
Thanks a lot for this, it seems to be useful. I'm adapting it to reduce false negatives (e.g. omitting the check if the struct/union is already packed), and I imagine it could be made to only warn about padded unpacked structs/unions which are used as nested members of packed structs/unions. It wouldn't catch everything but would probably catch a lot of cases that are most likely to be genuine since they would have been packed at the outer level for a reason.
> Perhaps there could be a command line option or a pragma so that unions > will work in the kernel. We don't care about linking to outside > libraries.
We still interact with userland via structs and unions, so it would probably have to exclude anything in uapi/.
Cheers James
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