[Qemu-devel] [PATCH] linux-user: Forget about synchronous signal once it is delivered

[Peter Maydell <peter.maydell@linaro.org>]

Commit 655ed67c2a248cf which switched synchronous signals to
benig recorded in ts->sync_signal rather than in a queue
with every other signal had a bug: we failed to clear
the flag indicating that a synchronous signal was pending
when we delivered it. This meant that we would take the signal
again and again every time the guest made a syscall.
(This is a bug introduced in my refactoring of Timothy Baldwin's
original code.)

Fix this by passing in the struct emulated_sigtable* to
handle_pending_signal(), so that we clear the pending flag
in the ts->sync_signal struct when handling a synchronous signal.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Found this when investigating why one of the gcc test suite tests
was crashing...

 linux-user/signal.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 9d98045..9a4d894 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -5826,7 +5826,8 @@ long do_rt_sigreturn(CPUArchState *env)
 
 #endif
 
-static void handle_pending_signal(CPUArchState *cpu_env, int sig)
+static void handle_pending_signal(CPUArchState *cpu_env, int sig,
+                                  struct emulated_sigtable *k)
 {
     CPUState *cpu = ENV_GET_CPU(cpu_env);
     abi_ulong handler;
@@ -5834,7 +5835,6 @@ static void handle_pending_signal(CPUArchState *cpu_env, int sig)
     target_sigset_t target_old_set;
     struct target_sigaction *sa;
     TaskState *ts = cpu->opaque;
-    struct emulated_sigtable *k = &ts->sigtab[sig - 1];
 
     trace_user_handle_signal(cpu_env, sig);
     /* dequeue signal */
@@ -5937,7 +5937,7 @@ void process_pending_signals(CPUArchState *cpu_env)
                 sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL;
             }
 
-            handle_pending_signal(cpu_env, sig);
+            handle_pending_signal(cpu_env, sig, &ts->sync_signal);
         }
 
         for (sig = 1; sig <= TARGET_NSIG; sig++) {
@@ -5947,7 +5947,7 @@ void process_pending_signals(CPUArchState *cpu_env)
             if (ts->sigtab[sig - 1].pending &&
                 (!sigismember(blocked_set,
                               target_to_host_signal_table[sig]))) {
-                handle_pending_signal(cpu_env, sig);
+                handle_pending_signal(cpu_env, sig, &ts->sigtab[sig - 1]);
                 /* Restart scan from the beginning */
                 sig = 1;
             }
-- 
1.9.1