From: "H. Peter Anvin" <hpa@zytor.com>
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>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Guo Ren <guoren@kernel.org>, 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
Subject: Re: [PATCH v3 00/23] Add generic vdso_base tracking
Date: Wed, 11 Oct 2023 16:20:06 -0700 [thread overview]
Message-ID: <eec6b477-67b5-49d6-b6f4-dd2c242b9bdb@zytor.com> (raw)
In-Reply-To: <20210611180242.711399-1-dima@arista.com>
On 6/11/21 11:02, Dmitry Safonov wrote:
>
> 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).
>
> Logically, the patches set divides on:
> - patch 1: a cleanup for patches in x86/cleanups
> - patches 2-13: cleanups for arch_setup_additional_pages()
> - patches 13-14: x86 signal changes for unmapped vdso
> - patches 15-22: provide generic vdso_base in mm_struct
> - patch 23: selftest for unmapped vDSO & fast syscalls
>
> 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)
>
There was another discussion that might be relevant: actually
associating the vdso with an actual file, and allowing a program to map
said file normally if it want access to one that it normally wouldn't
have (say, /proc/vdso/x86_64.so versus /proc/vdso/i386.so on the same
system.)
The "catch", of course, is that this file will need to be mapped as
MAP_SHARED because of vdso data.
-hpa
prev parent reply other threads:[~2023-10-11 23:21 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-11 18:02 [PATCH v3 00/23] Add generic vdso_base tracking Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 01/23] x86/elf: Check in_x32_syscall() in compat_arch_setup_additional_pages() Dmitry Safonov
2021-06-19 20:41 ` Thomas Gleixner
2021-06-21 20:59 ` Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 02/23] elf: Move arch_setup_additional_pages() to generic elf.h Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 03/23] arm/elf: Remove needless ifdef CONFIG_MMU Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 04/23] arm64: Use in_compat_task() in arch_setup_additional_pages() Dmitry Safonov
2021-06-15 10:21 ` Will Deacon
2021-06-11 18:02 ` [PATCH v3 05/23] x86: Remove compat_arch_setup_additional_pages() Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 06/23] elf: " Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 07/23] vdso: Set mm->context.vdso only on success of _install_special_mapping() Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 08/23] elf/vdso: Modify arch_setup_additional_pages() parameters Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 09/23] elf: Use sysinfo_ehdr in ARCH_DLINFO() Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 10/23] arm/vdso: Remove vdso pointer from mm->context Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 11/23] s390/vdso: Remove vdso_base " Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 12/23] sparc/vdso: Remove vdso " Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 13/23] mm/mmap: Make vm_special_mapping::mremap return void Dmitry Safonov
2021-06-17 7:20 ` Christophe Leroy
2021-06-21 21:12 ` Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 14/23] x86/signal: Land on &frame->retcode when vdso isn't mapped Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 15/23] x86/signal: Check if vdso_image_32 is mapped before trying to land on it Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 16/23] mm: Add vdso_base in mm_struct Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 17/23] x86/vdso: Migrate to generic vdso_base Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 18/23] arm/vdso: " Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 19/23] arm64/vdso: Migrate compat signals " Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 20/23] arm64/vdso: Migrate native " Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 21/23] mips/vdso: Migrate " Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 22/23] powerpc/vdso: Migrate native signals " Dmitry Safonov
2021-06-15 12:52 ` Michael Ellerman
2021-06-17 6:30 ` Christophe Leroy
2021-06-17 6:36 ` Christophe Leroy
2021-06-17 7:34 ` Christophe Leroy
2021-06-21 21:22 ` Dmitry Safonov
2021-06-11 18:02 ` [PATCH v3 23/23] x86/vdso/selftest: Add a test for unmapping vDSO Dmitry Safonov
2021-06-11 18:21 ` Shuah Khan
2021-06-11 18:37 ` Dmitry Safonov
2021-06-11 18:43 ` Shuah Khan
2021-06-17 9:13 ` [PATCH v3 00/23] Add generic vdso_base tracking Christophe Leroy
2021-06-21 21:57 ` Dmitry Safonov
2022-03-09 15:41 ` Christophe Leroy
2022-03-10 21:17 ` Dmitry Safonov
2022-08-19 9:17 ` Christophe Leroy
2022-08-23 19:13 ` Dmitry Safonov
2023-10-11 10:28 ` Christophe Leroy
2023-10-11 23:20 ` H. Peter Anvin [this message]
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