Messages in this thread | | | Date | Wed, 22 Feb 2023 12:33:29 -0800 | Subject | Re: [PATCH RESEND 1/1] check-uapi: Introduce check-uapi.sh | From | John Moon <> |
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On 2/18/2023 12:17 AM, Greg Kroah-Hartman wrote: > On Fri, Feb 17, 2023 at 12:22:34PM -0800, John Moon wrote: >> While the kernel community has been good at maintaining backwards >> compatibility with kernel UAPIs, it would be helpful to have a tool >> to check if a patch introduces changes that break backwards >> compatibility. >> >> To that end, introduce check-uapi.sh: a simple shell script that >> checks for changes to UAPI headers using libabigail. >> >> libabigail is "a framework which aims at helping developers and >> software distributors to spot some ABI-related issues like interface >> incompatibility in ELF shared libraries by performing a static >> analysis of the ELF binaries at hand." >> >> The script uses one of libabigail's tools, "abidiff", to compile the >> changed header before and after the patch to detect any changes. >> >> abidiff "compares the ABI of two shared libraries in ELF format. It >> emits a meaningful report describing the differences between the two >> ABIs." >> >> Signed-off-by: John Moon <quic_johmoo@quicinc.com> >> --- >> scripts/check-uapi.sh | 245 ++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 245 insertions(+) >> create mode 100755 scripts/check-uapi.sh > > Ok, this is very cool, thank you so much for doing this. > > I know Randy Dunlap was also looking into this previously, so I've cc:ed > him and bounced him the original. >
Okay, will keep him in the loop!
> I tried this out, and at first glance, this felt like it was just "too > fast" in that nothing actually was being tested. So I manually added a > field to a structure I know would break the abi, and: > > $ ./scripts/check-uapi.sh > !!! ABI differences detected in include/uapi/linux/usb/ch9.h (compared to file at HEAD^1) !!! > > [C] 'struct usb_ctrlrequest' changed: > type size changed from 64 to 72 (in bits) > 1 data member insertion: > '__u8 abi_break', at offset 16 (in bits) at ch9.h:216:1 > 3 data member changes: > '__le16 wValue' offset changed from 16 to 24 (in bits) (by +8 bits) > '__le16 wIndex' offset changed from 32 to 40 (in bits) (by +8 bits) > '__le16 wLength' offset changed from 48 to 56 (in bits) (by +8 bits) > > 0/1 UAPI header file changes are backwards compatible > UAPI header ABI check failed > > So it worked! > > There is a mismatch of different bash coding styles in the document, which > isn't a big deal, and one warning produced by the `shellcheck` tool, but that > can all be fixed up later. I'll go queue this up now, as a starting point for > people to play with, thanks! >
Will resolve all shellcheck warnings in next rev. Not sure about the coding style differences you're referring to - is there a shell script coding style document?
> Also, it would be nice to be able to check if the current tree with changes in > it (not checked in, just modified) breaks the abi, without having to go and > check the change in. But again, future fixups for people to do! >
Should be straightforward to add. Since I'm making another rev, I'll take care of this as well.
> thanks, > > greg k-h
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