From: ldv@altlinux.org (Dmitry V. Levin) Date: Thu, 12 Apr 2018 04:34:35 +0300 Subject: sparc/ppc/arm compat siginfo ABI regressions: sending SIGFPE via kill() returns wrong values in si_pid and si_uid In-Reply-To: <20180409152253.GD10489@altlinux.org> References: <20180409152253.GD10489@altlinux.org> Message-ID: <20180412013435.GA21219@altlinux.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Mon, Apr 09, 2018 at 06:22:53PM +0300, Dmitry V. Levin wrote: > There seems to be a regression in v4.16 on ppc compat very similar > to sparc compat regression reported earlier at > https://marc.info/?l=linux-sparc&m=151501500704383 . > > The symptoms are exactly the same: the same signal_receive test from > the strace test suite fails with the same diagnostics: > https://build.opensuse.org/public/build/home:ldv_alt/openSUSE_Factory_PowerPC/ppc/strace/_log The log is big, just look for "KERNEL BUG". > Unfortunately, I do not have any means to investigate further, > so just passing this information on to those who care. OK, the faulty commit is v4.16-rc1~159^2~39 ("signal/powerpc: Document conflicts with SI_USER and SIGFPE and SIGTRAP"). One might think that a commit called "Document conflicts" shouldn't introduce an ABI regression, but this one definitely does by defining FPE_FIXME and TRAP_FIXME in arch/powerpc/include/uapi/asm/siginfo.h that affect siginfo_layout(). A similar commit v4.16-rc1~159^2~37 ("signal/arm: Document conflicts with SI_USER and SIGFPE") must have introduced a similar ABI regression to compat arm. An earlier commit v4.14-rc1~60^2^2~5 ("signal/sparc: Document a conflict with SI_USER with SIGFPE") introduced a similar ABI regression to compat sparc. There is a clear pattern of sneaking in ABI changes using innocently looking commit messages. -- ldv -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 801 bytes Desc: not available URL: