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[Qemu-devel] [PATCH 0/3] linux-user/sparc: Fixes for clone
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 0/3] linux-user/sparc: Fixes for clone |
Date: |
Mon, 30 Jul 2018 16:15:49 -0400 |
There are at least 4 separate bugs preventing clone from working.
(1) cpu_copy left both cpus sharing the same register window (!)
(2) cpu_clone_regs did not initialize %o1, so the new thread path
in the guest __clone was always taken, even for the parent
(old %o1 value was newsp, and so non-zero).
(3) cpu_clone_regs did not advance the pc past the syscall in the
child, which meant that the child re-executed the syscall
(and because of (1), with essentially random inputs).
(4) clone did not flush register windows, which would cause the
parent stack to be clobbered by the child writing out old
windows in order to allocate a new one.
This is enough for Alex's atomic-test to make progress, but not
quite enough for it to actually work. What I'm seeing now is a
legitimate SEGV for a write to a r-xp memory segment. I'll need
to examine the testcase further to see why that is happening.
r~
Richard Henderson (4):
linux-user: Disallow setting newsp for fork
linux-user: Pass the parent env to cpu_clone_regs
linux-user/sparc: Fix cpu_clone_regs
linux-user/sparc: Flush register windows before clone
linux-user/aarch64/target_cpu.h | 3 ++-
linux-user/alpha/target_cpu.h | 3 ++-
linux-user/arm/target_cpu.h | 3 ++-
linux-user/cris/target_cpu.h | 3 ++-
linux-user/hppa/target_cpu.h | 3 ++-
linux-user/i386/target_cpu.h | 3 ++-
linux-user/m68k/target_cpu.h | 3 ++-
linux-user/microblaze/target_cpu.h | 3 ++-
linux-user/mips/target_cpu.h | 3 ++-
linux-user/nios2/target_cpu.h | 3 ++-
linux-user/openrisc/target_cpu.h | 4 +++-
linux-user/ppc/target_cpu.h | 3 ++-
linux-user/riscv/target_cpu.h | 3 ++-
linux-user/s390x/target_cpu.h | 3 ++-
linux-user/sh4/target_cpu.h | 3 ++-
linux-user/sparc/target_cpu.h | 23 ++++++++++++++++++++---
linux-user/tilegx/target_cpu.h | 3 ++-
linux-user/xtensa/target_cpu.h | 3 ++-
linux-user/sparc/cpu_loop.c | 3 +++
linux-user/syscall.c | 9 ++++++---
20 files changed, 64 insertions(+), 23 deletions(-)
--
2.17.1
- [Qemu-devel] [PATCH 0/3] linux-user/sparc: Fixes for clone,
Richard Henderson <=
- [Qemu-devel] [PATCH 1/4] linux-user: Disallow setting newsp for fork, Richard Henderson, 2018/07/30
- [Qemu-devel] [PATCH 3/4] linux-user/sparc: Fix cpu_clone_regs, Richard Henderson, 2018/07/30
- [Qemu-devel] [PATCH 2/4] linux-user: Pass the parent env to cpu_clone_regs, Richard Henderson, 2018/07/30
- [Qemu-devel] [PATCH 4/4] linux-user/sparc: Flush register windows before clone, Richard Henderson, 2018/07/30
- Re: [Qemu-devel] [PATCH 0/3] linux-user/sparc: Fixes for clone, Alex Bennée, 2018/07/31