From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Dmitry Safonov <dima@arista.com>, linux-kernel@vger.kernel.org
Cc: Dmitry Safonov <0x7f454c46@gmail.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
Borislav Petkov <bp@alien8.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Guo Ren <guoren@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Ingo Molnar <mingo@redhat.com>, Oleg Nesterov <oleg@redhat.com>,
Russell King <linux@armlinux.org.uk>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Thomas Gleixner <tglx@linutronix.de>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Will Deacon <will@kernel.org>,
x86@kernel.org,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2 00/19] Add generic vdso_base tracking
Date: Tue, 24 Nov 2020 07:53:58 +0100 [thread overview]
Message-ID: <5e315bf6-b03d-e66e-9557-22ece397080e@csgroup.eu> (raw)
In-Reply-To: <20201124002932.1220517-1-dima@arista.com>
Le 24/11/2020 à 01:29, Dmitry Safonov a écrit :
> v2 Changes:
> - Rename user_landing to vdso_base as it tracks vDSO VMA start address,
> rather than the explicit address to land (Andy)
> - Reword and don't use "new-execed" and "new-born" task (Andy)
> - Fix failures reported by build robot
>
> Started from discussion [1], where was noted that currently a couple of
> architectures support mremap() for vdso/sigpage, but not munmap().
> If an application maps something on the ex-place of vdso/sigpage,
> later after processing signal it will land there (good luck!)
>
> Patches set is based on linux-next (next-20201123) and it depends on
> changes in x86/cleanups (those reclaim TIF_IA32/TIF_X32) and also
> on my changes in akpm (fixing several mremap() issues).
I have a series that cleans up VDSO init on powerpc and migrates powerpc to
_install_special_mapping() (patch 10 of the series).
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=204396&state=%2A&archive=both
I'm wondering how we should coordinate with your series for merging.
I guess your series will also imply removal of arch_unmap() ? see
https://elixir.bootlin.com/linux/v5.10-rc4/source/arch/powerpc/include/asm/mmu_context.h#L262
>
> Logically, the patches set divides on:
> - patch 1: a cleanup for patches in x86/cleanups
> - patches 2-11: cleanups for arch_setup_additional_pages()
> - patches 12-13: x86 signal changes for unmapped vdso
> - patches 14-19: provide generic vdso_base in mm_struct
>
> In the end, besides cleanups, it's now more predictable what happens for
> applications with unmapped vdso on architectures those support .mremap()
> for vdso/sigpage.
>
> I'm aware of only one user that unmaps vdso - Valgrind [2].
> (there possibly are more, but this one is "special", it unmaps vdso, but
> not vvar, which confuses CRIU [Checkpoint Restore In Userspace], that's
> why I'm aware of it)
>
> Patches as a .git branch:
> https://github.com/0x7f454c46/linux/tree/setup_additional_pages-v2
>
> v1 Link:
> https://lore.kernel.org/lkml/20201108051730.2042693-1-dima@arista.com/
>
> [1]: https://lore.kernel.org/linux-arch/CAJwJo6ZANqYkSHbQ+3b+Fi_VT80MtrzEV5yreQAWx-L8j8x2zA@mail.gmail.com/
> [2]: https://github.com/checkpoint-restore/criu/issues/488
>
Christophe
next prev parent reply other threads:[~2020-11-24 6:54 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 0:29 Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 01/19] x86/elf: Check in_x32_syscall() in compat_arch_setup_additional_pages() Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 02/19] elf: Move arch_setup_additional_pages() to generic elf.h Dmitry Safonov
2020-11-24 6:12 ` Christophe Leroy
2020-11-26 19:45 ` Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 03/19] arm64: Use in_compat_task() in arch_setup_additional_pages() Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 04/19] x86: Remove compat_arch_setup_additional_pages() Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 05/19] elf: " Dmitry Safonov
2020-11-24 6:13 ` Christophe Leroy
2020-11-26 19:45 ` Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 06/19] elf/vdso: Reuse arch_setup_additional_pages() parameters Dmitry Safonov
2020-11-24 6:18 ` Christophe Leroy
2020-11-26 19:46 ` Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 07/19] elf: Use sysinfo_ehdr in ARCH_DLINFO() Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 08/19] arm/vdso: Remove vdso pointer from mm->context Dmitry Safonov
2020-11-24 6:22 ` Christophe Leroy
2020-11-26 19:48 ` Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 09/19] s390/vdso: Remove vdso_base " Dmitry Safonov
2020-11-24 6:22 ` Christophe Leroy
2020-11-24 0:29 ` [PATCH v2 10/19] sparc/vdso: Remove vdso " Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 11/19] mm/mmap: Make vm_special_mapping::mremap return void Dmitry Safonov
2020-11-24 6:25 ` Christophe Leroy
2020-11-24 0:29 ` [PATCH v2 12/19] x86/signal: Land on &frame->retcode when vdso isn't mapped Dmitry Safonov
2020-11-24 23:08 ` Andy Lutomirski
2020-11-24 0:29 ` [PATCH v2 13/19] x86/signal: Check if vdso_image_32 is mapped before trying to land on it Dmitry Safonov
2020-11-24 23:43 ` Andy Lutomirski
2020-11-26 20:00 ` Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 14/19] mm: Add vdso_base in mm_struct Dmitry Safonov
2020-11-24 23:37 ` Andy Lutomirski
2020-11-24 0:29 ` [PATCH v2 15/19] x86/vdso: Migrate to generic vdso_base Dmitry Safonov
2020-11-24 2:51 ` kernel test robot
2020-11-24 0:29 ` [PATCH v2 16/19] arm/vdso: " Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 17/19] arm64/vdso: Migrate compat signals " Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 18/19] arm64/vdso: Migrate native " Dmitry Safonov
2020-11-24 0:29 ` [PATCH v2 19/19] mips/vdso: Migrate " Dmitry Safonov
2020-11-24 6:53 ` Christophe Leroy [this message]
2020-11-26 20:41 ` [PATCH v2 00/19] Add generic vdso_base tracking Dmitry Safonov
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