From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from vmicros1.altlinux.org (vmicros1.altlinux.org [194.107.17.57]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5445344CF52 for ; Thu, 23 Jul 2026 11:10:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.107.17.57 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784805026; cv=none; b=gZscGHu3RwYTkssuFXhpwutFjIECB28UKrYdkju9bdBmVfHvfGGnwtpYI4SkQuq4z9BBWD/A7BFQ/9Hu5QkLIHISc0C85noiDdtJbAAVeixwtJpNHVo8qv7XKr15Ggv5qXt0Nwt9kYECWSgL1mfGx2Ej1M2A8W71l37S3u857LQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784805026; c=relaxed/simple; bh=cbv01YFkYU4T1kKtVXUWnEqakmnVlbHxUCbZAIQeWWw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kAj7/NEyDLX65g8ocV0Gdp2RK/2/HiOITKd1Qrxy8qdaCME2D9pgbjcfYxiX/HfcOWqbYJz0iNtvREG2T04CjU2KR4W5erHS2HmaTCtGpyAdebEewoL8BTR94nxszQ4X9v6eEN/AqIjbY0MBYUqGJ5PMU50Y7ZeL0PPmbGdbygY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strace.io; spf=pass smtp.mailfrom=altlinux.org; arc=none smtp.client-ip=194.107.17.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strace.io Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=altlinux.org Received: from mua.local.altlinux.org (mua.local.altlinux.org [192.168.1.14]) by vmicros1.altlinux.org (Postfix) with ESMTP id 1AEC872C8F5; Thu, 23 Jul 2026 14:10:16 +0300 (MSK) Received: by mua.local.altlinux.org (Postfix, from userid 508) id 0C0957CCB3A; Thu, 23 Jul 2026 14:10:16 +0300 (IDT) Date: Thu, 23 Jul 2026 14:10:16 +0300 From: "Dmitry V. Levin" To: Mukesh Kumar Chaurasiya Cc: Mukesh Kumar Chaurasiya , maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, oleg@redhat.com, kees@kernel.org, luto@amacapital.net, wad@chromium.org, mchauras@linux.ibm.com, thuth@redhat.com, ruanjinjie@huawei.com, sshegde@linux.ibm.com, akpm@linux-foundation.org, charlie@rivosinc.com, deller@gmx.de, macro@orcam.me.uk, segher@kernel.crashing.org, peterz@infradead.org, bigeasy@linutronix.de, namcao@linutronix.de, tglx@linutronix.de, mark.barnett@arm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: Re: [PATCH v4 5/8] powerpc: add exit_flags field in pt_regs Message-ID: <20260723111015.GA27638@strace.io> References: <20260123073916.956498-1-mkchauras@linux.ibm.com> <20260123073916.956498-6-mkchauras@linux.ibm.com> <20260722070155.GA11808@strace.io> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Jul 23, 2026 at 03:02:38PM +0530, Mukesh Kumar Chaurasiya wrote: > On Wed, Jul 22, 2026 at 10:01:55AM +0300, Dmitry V. Levin wrote: > > On Fri, Jan 23, 2026 at 01:09:13PM +0530, Mukesh Kumar Chaurasiya wrote: > > > From: Mukesh Kumar Chaurasiya > > > > > > Add a new field `exit_flags` in the pt_regs structure. This field will hold > > > the flags set during interrupt or syscall execution that are required during > > > exit to user mode. > > > > Apparently, this change breaks PTRACE_GETREGS as the latter has no means > > to communicate the size of struct pt_regs being written to userspace. > > > > As result, the kernel with this patch will write to userpsace 32 more > > bytes than before, and unless the userspace is re-compiled with the latest > > ptrace.h, 32 bytes of userspace memory after struct pt_regs will be > > overwritten. > > > > This issue was detected by strace test suite, specifically, the test that > > checks whether the actual number of bytes written by > > ptrace(PTRACE_GETREGS) matches sizeof(struct pt_regs), and that test failed > > with runtime version v7.1 and headers version v7.2-rc1. > > > [...] > > Hey, > > Can you try this fix? This should fix the ABI breakage. [...] > diff --git a/arch/powerpc/include/uapi/asm/ptrace.h b/arch/powerpc/include/uapi/asm/ptrace.h > index a393b7f2760a..01e630149d48 100644 > --- a/arch/powerpc/include/uapi/asm/ptrace.h > +++ b/arch/powerpc/include/uapi/asm/ptrace.h > @@ -55,8 +55,6 @@ struct pt_regs > unsigned long dar; /* Fault registers */ > unsigned long dsisr; /* on 4xx/Book-E used for ESR */ > unsigned long result; /* Result of a system call */ > - unsigned long exit_flags; /* System call exit flags */ > - unsigned long __pt_regs_pad[3]; /* Maintain 16 byte interrupt stack alignment */ > }; > > #endif /* __ASSEMBLER__ */ > @@ -116,12 +114,10 @@ struct pt_regs > #define PT_DAR 41 > #define PT_DSISR 42 > #define PT_RESULT 43 > -#define PT_EXIT_FLAGS 44 > -#define PT_PAD 47 /* 3 times */ > -#define PT_DSCR 48 > -#define PT_REGS_COUNT 48 > +#define PT_DSCR 44 > +#define PT_REGS_COUNT 44 > > -#define PT_FPR0 (PT_REGS_COUNT + 4) /* each FP reg occupies 2 slots in this space */ > +#define PT_FPR0 48 /* each FP reg occupies 2 slots in this space */ > > #ifndef __powerpc64__ > > @@ -133,7 +129,7 @@ struct pt_regs > #define PT_FPSCR (PT_FPR0 + 32) /* each FP reg occupies 1 slot in 64-bit space */ > > > -#define PT_VR0 (PT_FPSCR + 2) /* <82> each Vector reg occupies 2 slots in 64-bit */ > +#define PT_VR0 82 /* each Vector reg occupies 2 slots in 64-bit */ > #define PT_VSCR (PT_VR0 + 32*2 + 1) > #define PT_VRSAVE (PT_VR0 + 33*2) > > @@ -141,7 +137,7 @@ struct pt_regs > /* > * Only store first 32 VSRs here. The second 32 VSRs in VR0-31 > */ > -#define PT_VSR0 (PT_VRSAVE + 2) /* each VSR reg occupies 2 slots in 64-bit */ > +#define PT_VSR0 150 /* each VSR reg occupies 2 slots in 64-bit */ > #define PT_VSR31 (PT_VSR0 + 2*31) > #endif /* __powerpc64__ */ > As this patch essentially reverts the uapi header to its v7.1 state, the uapi part of the patch is definitely fine. -- ldv