From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Dufour Subject: Re: [PATCH v2 2/2] powerpc/mm: Tracking vDSO remap Date: Wed, 25 Mar 2015 14:25:16 +0100 Message-ID: <5512B73C.5050509@linux.vnet.ibm.com> References: <20150323085209.GA28965@gmail.com> <25152b76585716dc635945c3455ab9b49e645f6d.1427280806.git.ldufour@linux.vnet.ibm.com> <20150325121118.GA2542@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150325121118.GA2542@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org, cov@codeaurora.org, criu@openvz.org List-Id: linux-arch.vger.kernel.org On 25/03/2015 13:11, Ingo Molnar wrote: > > * Laurent Dufour wrote: > >> Some processes (CRIU) are moving the vDSO area using the mremap system >> call. As a consequence the kernel reference to the vDSO base address is >> no more valid and the signal return frame built once the vDSO has been >> moved is not pointing to the new sigreturn address. >> >> This patch handles vDSO remapping and unmapping. >> >> Signed-off-by: Laurent Dufour >> --- >> arch/powerpc/include/asm/mmu_context.h | 36 +++++++++++++++++++++++++++++++++- >> 1 file changed, 35 insertions(+), 1 deletion(-) >> >> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h >> index 73382eba02dc..be5dca3f7826 100644 >> --- a/arch/powerpc/include/asm/mmu_context.h >> +++ b/arch/powerpc/include/asm/mmu_context.h >> @@ -8,7 +8,6 @@ >> #include >> #include >> #include >> -#include >> #include >> >> /* >> @@ -109,5 +108,40 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, >> #endif >> } >> >> +static inline void arch_dup_mmap(struct mm_struct *oldmm, >> + struct mm_struct *mm) >> +{ >> +} >> + >> +static inline void arch_exit_mmap(struct mm_struct *mm) >> +{ >> +} >> + >> +static inline void arch_unmap(struct mm_struct *mm, >> + struct vm_area_struct *vma, >> + unsigned long start, unsigned long end) >> +{ >> + if (start <= mm->context.vdso_base && mm->context.vdso_base < end) >> + mm->context.vdso_base = 0; >> +} >> + >> +static inline void arch_bprm_mm_init(struct mm_struct *mm, >> + struct vm_area_struct *vma) >> +{ >> +} >> + >> +#define __HAVE_ARCH_REMAP >> +static inline void arch_remap(struct mm_struct *mm, >> + unsigned long old_start, unsigned long old_end, >> + unsigned long new_start, unsigned long new_end) >> +{ >> + /* >> + * mremap don't allow moving multiple vma so we can limit the check >> + * to old_start == vdso_base. > > s/mremap don't allow moving multiple vma > mremap() doesn't allow moving multiple vmas > > right? Sure you're right. I'll provide a v3 fixing that comment. Thanks, Laurent. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e06smtp12.uk.ibm.com ([195.75.94.108]:40047 "EHLO e06smtp12.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752625AbbCYNZ3 (ORCPT ); Wed, 25 Mar 2015 09:25:29 -0400 Received: from /spool/local by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Mar 2015 13:25:27 -0000 Message-ID: <5512B73C.5050509@linux.vnet.ibm.com> Date: Wed, 25 Mar 2015 14:25:16 +0100 From: Laurent Dufour MIME-Version: 1.0 Subject: Re: [PATCH v2 2/2] powerpc/mm: Tracking vDSO remap References: <20150323085209.GA28965@gmail.com> <25152b76585716dc635945c3455ab9b49e645f6d.1427280806.git.ldufour@linux.vnet.ibm.com> <20150325121118.GA2542@gmail.com> In-Reply-To: <20150325121118.GA2542@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Ingo Molnar Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org, cov@codeaurora.org, criu@openvz.org Message-ID: <20150325132516.M1WAKgWeJhUZ72QJ5l21JpyI7m-hj8nei3AubT35OXM@z> On 25/03/2015 13:11, Ingo Molnar wrote: > > * Laurent Dufour wrote: > >> Some processes (CRIU) are moving the vDSO area using the mremap system >> call. As a consequence the kernel reference to the vDSO base address is >> no more valid and the signal return frame built once the vDSO has been >> moved is not pointing to the new sigreturn address. >> >> This patch handles vDSO remapping and unmapping. >> >> Signed-off-by: Laurent Dufour >> --- >> arch/powerpc/include/asm/mmu_context.h | 36 +++++++++++++++++++++++++++++++++- >> 1 file changed, 35 insertions(+), 1 deletion(-) >> >> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h >> index 73382eba02dc..be5dca3f7826 100644 >> --- a/arch/powerpc/include/asm/mmu_context.h >> +++ b/arch/powerpc/include/asm/mmu_context.h >> @@ -8,7 +8,6 @@ >> #include >> #include >> #include >> -#include >> #include >> >> /* >> @@ -109,5 +108,40 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, >> #endif >> } >> >> +static inline void arch_dup_mmap(struct mm_struct *oldmm, >> + struct mm_struct *mm) >> +{ >> +} >> + >> +static inline void arch_exit_mmap(struct mm_struct *mm) >> +{ >> +} >> + >> +static inline void arch_unmap(struct mm_struct *mm, >> + struct vm_area_struct *vma, >> + unsigned long start, unsigned long end) >> +{ >> + if (start <= mm->context.vdso_base && mm->context.vdso_base < end) >> + mm->context.vdso_base = 0; >> +} >> + >> +static inline void arch_bprm_mm_init(struct mm_struct *mm, >> + struct vm_area_struct *vma) >> +{ >> +} >> + >> +#define __HAVE_ARCH_REMAP >> +static inline void arch_remap(struct mm_struct *mm, >> + unsigned long old_start, unsigned long old_end, >> + unsigned long new_start, unsigned long new_end) >> +{ >> + /* >> + * mremap don't allow moving multiple vma so we can limit the check >> + * to old_start == vdso_base. > > s/mremap don't allow moving multiple vma > mremap() doesn't allow moving multiple vmas > > right? Sure you're right. I'll provide a v3 fixing that comment. Thanks, Laurent.