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From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, Douglas Crosher <dtc-ubuntu@scieneer.com>
Subject: [PULL 01/10] tcg: update the cpu running flag in cpu_exec_step_atomic
Date: Sat, 23 Jan 2021 08:50:11 -1000
Message-ID: <20210123185020.1766324-2-richard.henderson@linaro.org> (raw)
In-Reply-To: <20210123185020.1766324-1-richard.henderson@linaro.org>

From: Douglas Crosher <dtc-ubuntu@scieneer.com>

The cpu_exec_step_atomic() function is called with the cpu->running
clear and proceeds to run target code without setting this flag. If
this target code generates an exception then handle_cpu_signal() will
unnecessarily abort.  For example if atomic code generates a memory
protection fault.

This patch at least sets and clears this running flag, and adds some
assertions to help detect other cases.

Signed-off-by: Douglas Crosher <dtc-ubuntu@scieneer.com>
Message-Id: <a272c656-f7c5-019d-1cc0-499b8f80f2fc@scieneer.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cpu-exec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index e0df9b6a1d..8053aa3f11 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -285,6 +285,9 @@ void cpu_exec_step_atomic(CPUState *cpu)
 
     if (sigsetjmp(cpu->jmp_env, 0) == 0) {
         start_exclusive();
+        g_assert(cpu == current_cpu);
+        g_assert(!cpu->running);
+        cpu->running = true;
 
         tb = tb_lookup__cpu_state(cpu, &pc, &cs_base, &flags, cf_mask);
         if (tb == NULL) {
@@ -323,6 +326,7 @@ void cpu_exec_step_atomic(CPUState *cpu)
      */
     g_assert(cpu_in_exclusive_context(cpu));
     parallel_cpus = true;
+    cpu->running = false;
     end_exclusive();
 }
 
-- 
2.25.1



  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-23 18:50 [PULL 00/10] tcg patch queue Richard Henderson
2021-01-23 18:50 ` Richard Henderson [this message]
2021-01-23 18:50 ` [PULL 02/10] qemu/compiler: Split out qemu_build_not_reached_always Richard Henderson
2021-01-23 18:50 ` [PULL 03/10] tcg: Optimize inline dup_const for MO_64 Richard Henderson
2021-01-23 18:50 ` [PULL 04/10] tcg: Increase the static number of temporaries Richard Henderson
2021-01-23 18:50 ` [PULL 05/10] accel/tcg: Make cpu_gen_init() static Richard Henderson
2021-01-23 18:50 ` [PULL 06/10] accel/tcg: Move tb_flush_jmp_cache() to cputlb.c Richard Henderson
2021-01-23 18:50 ` [PULL 07/10] accel/tcg: Restrict tb_gen_code() from other accelerators Richard Henderson
2021-01-23 18:50 ` [PULL 08/10] accel/tcg: Declare missing cpu_loop_exit*() stubs Richard Henderson
2021-01-23 18:50 ` [PULL 09/10] accel/tcg: Restrict cpu_io_recompile() from other accelerators Richard Henderson
2021-01-23 18:50 ` [PULL 10/10] tcg: Toggle page execution for Apple Silicon Richard Henderson
2021-01-23 22:08 ` [PULL 00/10] tcg patch queue Richard Henderson

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