From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: John Moon <quic_johmoo@quicinc.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nicolas Schier <nicolas@fjasle.eu>,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-arm-msm@vger.kernel.org,
Randy Dunlap <rdunlap@infradead.org>,
Arnd Bergmann <arnd@arndb.de>,
Bjorn Andersson <andersson@kernel.org>,
Todd Kjos <tkjos@google.com>,
Matthias Maennich <maennich@google.com>,
Giuliano Procida <gprocida@google.com>,
kernel-team@android.com, libabigail@sourceware.org,
Jordan Crouse <jorcrous@amazon.com>,
Trilok Soni <quic_tsoni@quicinc.com>,
Satya Durga Srinivasu Prabhala <quic_satyap@quicinc.com>,
Elliot Berman <quic_eberman@quicinc.com>,
Guru Das Srinagesh <quic_gurus@quicinc.com>
Subject: Re: [PATCH v5 1/2] check-uapi: Introduce check-uapi.sh
Date: Wed, 12 Apr 2023 08:14:47 +0200 [thread overview]
Message-ID: <2023041209-armed-overlaid-3d3d@gregkh> (raw)
In-Reply-To: <bcdcee9b-f213-bc3c-d300-92a1e0138187@quicinc.com>
On Tue, Apr 11, 2023 at 11:36:48AM -0700, John Moon wrote:
> > >
> > > Others do not seem to be intentional:
> > >
> > > Addition/use of flex arrays:
> > > - include/uapi/linux/rseq.h (f7b01bb0b57f)
> > > - include/uapi/scsi/scsi_bsg_mpi3mr.h (c6f2e6b6eaaf)
> >
> > That is not a breakage, that's a tool problem.
> >
> > > Type change:
> > > - include/uapi/scsi/scsi_bsg_ufs.h (3f5145a615238)
> >
> > Again, not a real breakage, size is still the same.
> >
>
> Would you find the tool more useful if it simply filtered out all instances
> where the size of the type did not change? This would filter out the
> following which the tool currently flags:
>
> - enum expansions
> - reserved field expansions
> - expansions of a struct with a flex array at the end
> - type changes
> - re-ordering of existing members
> - ...others?
Obviously not, as some of those are real breakages, and some are not at
all.
Please understand what is an abi breakage. Adding new enums is not.
Using a reserved field is not. Reording existing members IS.
> These changes aren't _always_ safe, but if you assume the kernel developer
> is doing something reasonable, then maybe it's okay. Maybe we could hide
> these checks behind something like a "--pedantic" flag?
Again, no, that list above has totally different things in it, some are
completly safe, others totally break the abi. Do NOT lump them all
together as that is wrong.
thanks,
greg k-h
next prev parent reply other threads:[~2023-04-12 6:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-07 20:34 [PATCH v5 0/2] Validating UAPI backwards compatibility John Moon
2023-04-07 20:34 ` [PATCH v5 1/2] check-uapi: Introduce check-uapi.sh John Moon
2023-04-10 10:03 ` Masahiro Yamada
2023-04-10 18:45 ` Greg Kroah-Hartman
2023-04-10 23:32 ` John Moon
2023-04-11 6:34 ` Greg Kroah-Hartman
2023-04-11 18:36 ` John Moon
2023-04-12 6:14 ` Greg Kroah-Hartman [this message]
2023-04-12 16:37 ` John Moon
2023-04-12 16:43 ` Greg Kroah-Hartman
2023-04-13 17:07 ` John Moon
2023-04-13 18:22 ` Greg Kroah-Hartman
2023-04-13 14:37 ` Mark Wielaard
2023-04-13 17:12 ` Giuliano Procida
2023-04-13 17:15 ` John Moon
2023-04-13 17:03 ` Nicolas Schier
2023-04-13 17:33 ` John Moon
2023-07-20 16:10 ` [PATCH] scripts/check-uapi.sh: add stgdiff support Giuliano Procida
2023-07-22 19:40 ` Trilok Soni
2023-04-07 20:34 ` [PATCH v5 2/2] docs: dev-tools: Add UAPI checker documentation John Moon
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