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[PULL v2 3/8] linux-user: Always exit from exclusive state in fork_end()
From: |
Richard Henderson |
Subject: |
[PULL v2 3/8] linux-user: Always exit from exclusive state in fork_end() |
Date: |
Tue, 21 Feb 2023 16:00:18 -1000 |
From: Ilya Leoshkevich <iii@linux.ibm.com>
fork()ed processes currently start with
current_cpu->in_exclusive_context set, which is, strictly speaking, not
correct, but does not cause problems (even assertion failures).
With one of the next patches, the code begins to rely on this value, so
fix it by always calling end_exclusive() in fork_end().
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20230214140829.45392-2-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
linux-user/main.c | 10 ++++++----
linux-user/syscall.c | 1 +
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/linux-user/main.c b/linux-user/main.c
index 4290651c3c..4ff30ff980 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -161,13 +161,15 @@ void fork_end(int child)
}
qemu_init_cpu_list();
gdbserver_fork(thread_cpu);
- /* qemu_init_cpu_list() takes care of reinitializing the
- * exclusive state, so we don't need to end_exclusive() here.
- */
} else {
cpu_list_unlock();
- end_exclusive();
}
+ /*
+ * qemu_init_cpu_list() reinitialized the child exclusive state, but we
+ * also need to keep current_cpu consistent, so call end_exclusive() for
+ * both child and parent.
+ */
+ end_exclusive();
}
__thread CPUState *thread_cpu;
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 1e868e9b0e..a6c426d73c 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6752,6 +6752,7 @@ static int do_fork(CPUArchState *env, unsigned int flags,
abi_ulong newsp,
cpu_clone_regs_parent(env, flags);
fork_end(0);
}
+ g_assert(!cpu_in_exclusive_context(cpu));
}
return ret;
}
--
2.34.1
- [PULL v2 0/8] tcg patch queue, Richard Henderson, 2023/02/21
- [PULL v2 1/8] accel/tcg: Allow the second page of an instruction to be MMIO, Richard Henderson, 2023/02/21
- [PULL v2 2/8] linux-user/sparc: Raise SIGILL for all unhandled software traps, Richard Henderson, 2023/02/21
- [PULL v2 3/8] linux-user: Always exit from exclusive state in fork_end(),
Richard Henderson <=
- [PULL v2 5/8] linux-user/microblaze: Handle privileged exception, Richard Henderson, 2023/02/21
- [PULL v2 4/8] cpus: Make {start,end}_exclusive() recursive, Richard Henderson, 2023/02/21
- [PULL v2 6/8] target/microblaze: Add gdbstub xml, Richard Henderson, 2023/02/21
- [PULL v2 7/8] util/cacheflush: fix cache on windows-arm64, Richard Henderson, 2023/02/21
- [PULL v2 8/8] sysemu/os-win32: fix setjmp/longjmp on windows-arm64, Richard Henderson, 2023/02/21
- Re: [PULL v2 0/8] tcg patch queue, Peter Maydell, 2023/02/24