[PATCH v3 00/23] Add generic vdso_base tracking
From: Dmitry Safonov
Date: Fri Jun 11 2021 - 14:03:57 EST
v3 Changes:
- Migrated arch/powerpc to vdso_base
- Added x86/selftest for unmapped vdso & no landing on fast syscall
- Review comments from Andy & Christophe (thanks!)
- Amended s/born process/execed process/ everywhere I noticed
- Build robot warning on cast from __user pointer
I've tested it on x86, I would appreciate any help with
Tested-by on arm/arm64/mips/powerpc/s390/... platforms.
One thing I've noticed while cooking this and haven't found a clean
way to solve is zero-terminated .pages[] array in vdso mappings, which
is not always zero-terminated but works by the reason of
VM_DONTEXPAND on mappings.
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).
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)
Patches as a .git branch:
https://github.com/0x7f454c46/linux/tree/vdso_base-v3
v2 Link:
https://lore.kernel.org/lkml/20201124002932.1220517-1-dima@xxxxxxxxxx/
v1 Link:
https://lore.kernel.org/lkml/20201108051730.2042693-1-dima@xxxxxxxxxx/
[1]: https://lore.kernel.org/linux-arch/CAJwJo6ZANqYkSHbQ+3b+Fi_VT80MtrzEV5yreQAWx-L8j8x2zA@xxxxxxxxxxxxxx/
[2]: https://github.com/checkpoint-restore/criu/issues/488
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Guo Ren <guoren@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Dmitry Safonov (23):
x86/elf: Check in_x32_syscall() in
compat_arch_setup_additional_pages()
elf: Move arch_setup_additional_pages() to generic elf.h
arm/elf: Remove needless ifdef CONFIG_MMU
arm64: Use in_compat_task() in arch_setup_additional_pages()
x86: Remove compat_arch_setup_additional_pages()
elf: Remove compat_arch_setup_additional_pages()
vdso: Set mm->context.vdso only on success of
_install_special_mapping()
elf/vdso: Modify arch_setup_additional_pages() parameters
elf: Use sysinfo_ehdr in ARCH_DLINFO()
arm/vdso: Remove vdso pointer from mm->context
s390/vdso: Remove vdso_base pointer from mm->context
sparc/vdso: Remove vdso pointer from mm->context
mm/mmap: Make vm_special_mapping::mremap return void
x86/signal: Land on &frame->retcode when vdso isn't mapped
x86/signal: Check if vdso_image_32 is mapped before trying to land on it
mm: Add vdso_base in mm_struct
x86/vdso: Migrate to generic vdso_base
arm/vdso: Migrate to generic vdso_base
arm64/vdso: Migrate compat signals to generic vdso_base
arm64/vdso: Migrate native signals to generic vdso_base
mips/vdso: Migrate to generic vdso_base
powerpc/vdso: Migrate native signals to generic vdso_base
x86/vdso/selftest: Add a test for unmapping vDSO
arch/Kconfig | 3 +
arch/alpha/include/asm/elf.h | 2 +-
arch/arm/Kconfig | 2 +
arch/arm/include/asm/elf.h | 10 +-
arch/arm/include/asm/mmu.h | 3 -
arch/arm/include/asm/vdso.h | 6 +-
arch/arm/kernel/process.c | 14 +-
arch/arm/kernel/signal.c | 6 +-
arch/arm/kernel/vdso.c | 20 +--
arch/arm64/Kconfig | 2 +
arch/arm64/include/asm/elf.h | 27 +---
arch/arm64/include/asm/mmu.h | 4 -
arch/arm64/kernel/signal.c | 10 +-
arch/arm64/kernel/signal32.c | 17 +-
arch/arm64/kernel/vdso.c | 72 +++------
arch/csky/Kconfig | 1 +
arch/csky/include/asm/elf.h | 4 -
arch/csky/kernel/vdso.c | 11 +-
arch/hexagon/Kconfig | 1 +
arch/hexagon/include/asm/elf.h | 6 -
arch/hexagon/kernel/vdso.c | 3 +-
arch/ia64/include/asm/elf.h | 2 +-
arch/mips/Kconfig | 2 +
arch/mips/include/asm/elf.h | 10 +-
arch/mips/include/asm/mmu.h | 2 -
arch/mips/kernel/signal.c | 11 +-
arch/mips/kernel/vdso.c | 5 +-
arch/mips/vdso/genvdso.c | 9 --
arch/nds32/Kconfig | 1 +
arch/nds32/include/asm/elf.h | 8 +-
arch/nds32/kernel/vdso.c | 8 +-
arch/nios2/Kconfig | 1 +
arch/nios2/include/asm/elf.h | 4 -
arch/nios2/mm/init.c | 2 +-
arch/powerpc/Kconfig | 2 +
arch/powerpc/include/asm/book3s/32/mmu-hash.h | 1 -
arch/powerpc/include/asm/book3s/64/mmu.h | 1 -
arch/powerpc/include/asm/elf.h | 9 +-
arch/powerpc/include/asm/mmu_context.h | 9 --
arch/powerpc/include/asm/nohash/32/mmu-40x.h | 1 -
arch/powerpc/include/asm/nohash/32/mmu-44x.h | 1 -
arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 1 -
arch/powerpc/include/asm/nohash/mmu-book3e.h | 1 -
arch/powerpc/kernel/signal_32.c | 8 +-
arch/powerpc/kernel/signal_64.c | 4 +-
arch/powerpc/kernel/vdso.c | 48 +-----
arch/powerpc/perf/callchain_32.c | 8 +-
arch/powerpc/perf/callchain_64.c | 4 +-
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/elf.h | 9 +-
arch/riscv/kernel/vdso.c | 11 +-
arch/s390/Kconfig | 1 +
arch/s390/include/asm/elf.h | 10 +-
arch/s390/include/asm/mmu.h | 1 -
arch/s390/kernel/vdso.c | 12 +-
arch/sh/Kconfig | 1 +
arch/sh/include/asm/elf.h | 16 +-
arch/sh/kernel/vsyscall/vsyscall.c | 3 +-
arch/sparc/Kconfig | 1 +
arch/sparc/include/asm/elf_64.h | 11 +-
arch/sparc/include/asm/mmu_64.h | 1 -
arch/sparc/vdso/vma.c | 20 +--
arch/x86/Kconfig | 2 +
arch/x86/entry/common.c | 10 +-
arch/x86/entry/vdso/extable.c | 4 +-
arch/x86/entry/vdso/vma.c | 79 ++++-----
arch/x86/ia32/ia32_signal.c | 18 ++-
arch/x86/include/asm/compat.h | 6 +
arch/x86/include/asm/elf.h | 44 ++---
arch/x86/include/asm/mmu.h | 1 -
arch/x86/include/asm/mmu_context.h | 5 -
arch/x86/include/asm/vdso.h | 4 +
arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 3 +-
arch/x86/kernel/signal.c | 25 ++-
arch/x86/um/asm/elf.h | 9 +-
arch/x86/um/vdso/vma.c | 2 +-
fs/Kconfig.binfmt | 3 +
fs/aio.c | 3 +-
fs/binfmt_elf.c | 19 ++-
fs/binfmt_elf_fdpic.c | 17 +-
fs/compat_binfmt_elf.c | 12 --
include/asm-generic/mm_hooks.h | 9 +-
include/linux/elf.h | 24 ++-
include/linux/mm.h | 3 +-
include/linux/mm_types.h | 21 ++-
kernel/fork.c | 1 +
mm/mmap.c | 28 ++--
mm/mremap.c | 2 +-
tools/testing/selftests/x86/.gitignore | 1 +
tools/testing/selftests/x86/Makefile | 11 +-
.../testing/selftests/x86/test_munmap_vdso.c | 151 ++++++++++++++++++
91 files changed, 511 insertions(+), 491 deletions(-)
create mode 100644 tools/testing/selftests/x86/test_munmap_vdso.c
base-commit: 614124bea77e452aa6df7a8714e8bc820b489922
--
2.31.1