From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 090F9385803B; Thu, 10 Mar 2022 15:53:07 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 090F9385803B From: "woodard at redhat dot com" To: libabigail@sourceware.org Subject: [Bug default/28954] add Linux Kernel symbol namespace support Date: Thu, 10 Mar 2022 15:53:07 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: libabigail X-Bugzilla-Component: default X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: woodard at redhat dot com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: dodji at redhat dot com X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: libabigail@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Mailing list of the Libabigail project List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Mar 2022 15:53:08 -0000 https://sourceware.org/bugzilla/show_bug.cgi?id=3D28954 --- Comment #1 from Ben Woodard --- I=E2=80=99m a little confused by this the LKM name spacing doesn=E2=80=99t = seem to use any of the symbol mangling that C++ does. From the links that you posted it seems = like the way that the kernel mangles these names is simply by putting =E2=80=9C.= =E2=80=9D into the ELF linkage name. This confuses me because, I would think that this change in linkage name would show up in ABI reports but your bug description below suggests that it doesn=E2=80=99t. I must be missing something. -ben > On Mar 10, 2022, at 5:26 AM, gprocida at google dot com via Libabigail wrote: >=20 > =EF=BB=BFhttps://sourceware.org/bugzilla/show_bug.cgi?id=3D28954 >=20 > Bug ID: 28954 > Summary: add Linux Kernel symbol namespace support > Product: libabigail > Version: unspecified > Status: UNCONFIRMED > Severity: normal > Priority: P2 > Component: default > Assignee: dodji at redhat dot com > Reporter: gprocida at google dot com > CC: libabigail at sourceware dot org > Target Milestone: --- >=20 > Hi. >=20 > We have started to see Linux kernel symbol namespace changes break module > loading, without being picked up by ABI monitoring beforehand. >=20 > If a symbol has a namespace, then any module attempting to use it (run-ti= me > load check) must have imported (compile-time) the namespace. Load failure= can > be commuted to a warning but I doubt we would do that for Android. >=20 > In terms of ABI monitoring, a change to a symbol's namespace should be re= ported > as an ABI diff. >=20 > While it might also be nice to store the imported namespaces per module (= at the > abg-corpus level), without also tracking undefined symbols this wouldn't = allow > any automatic checking of kernel / module compatibility. Also, there is a > compile-time check that does that anyway. We are trying to ensure that > separately built kernel and modules will (continue to) work together. >=20 > At a minimum we need the following: >=20 > * new ELF symbol XML attribute (and possible documentation update) > * new field in ELF symbol > * symtab reader changes to populate this > * XML writer change to print this > * XML reader change to read this > * categorisation of symbol namespace changes (probably the same as for CR= Cs) > * symbol namespace diff generation / reporting >=20 > I'm happy to start work on this, but would welcome any early feedback. >=20 > References >=20 > https://www.kernel.org/doc/html/latest/core-api/symbol-namespaces.html > https://lwn.net/Articles/760045/ > https://lpc.events/event/2/contributions/220/attachments/44/51/01._Symbol= _Namespaces__Plumbers_v2.pdf >=20 > Giuliano. >=20 > --=20 > You are receiving this mail because: > You are on the CC list for the bug. > --=20 You are receiving this mail because: You are on the CC list for the bug.=