From: Nicholas Piggin <[email protected]> Synchronous signals must accommodate a synchronous signal being raised during delivery, as asynchronous ones do. For example badframe errors during delivery will cause SIGSEGV to be raised.
Without this fix, cpu_loop() runs process_pending_signals() which delivers the first synchronous signal (e.g., SIGILL) which fails to set the handler and forces SIGSEGV, but that is not picked up. process_pending_signals() returns. Then cpu_loop() runs cpu_exec() again, which attempts to execute the same instruction, another SIGILL. Signed-off-by: Nicholas Piggin <[email protected]> Reviewed-by: Warner Losh <[email protected]> Reviewed-by: Peter Maydell <[email protected]> Message-id: [email protected] Signed-off-by: Peter Maydell <[email protected]> (cherry picked from commit 7e966ef38f58f91e05a46fdfda4ba63a9a1567d6) Signed-off-by: Michael Tokarev <[email protected]> diff --git a/bsd-user/signal.c b/bsd-user/signal.c index a8cfcca130..1c73f03d80 100644 --- a/bsd-user/signal.c +++ b/bsd-user/signal.c @@ -999,7 +999,12 @@ void process_pending_signals(CPUArchState *env) sigdelset(&ts->signal_mask, target_to_host_signal(sig)); sigact_table[sig - 1]._sa_handler = TARGET_SIG_DFL; } + /* + * Restart scan from the beginning, as handle_pending_signal + * might have resulted in a new synchronous signal (eg SIGSEGV). + */ handle_pending_signal(env, sig, &ts->sync_signal); + goto restart_scan; } k = ts->sigtab; @@ -1009,10 +1014,7 @@ void process_pending_signals(CPUArchState *env) if (k->pending && !sigismember(blocked_set, target_to_host_signal(sig))) { handle_pending_signal(env, sig, k); - /* - * Restart scan from the beginning, as handle_pending_signal - * might have resulted in a new synchronous signal (eg SIGSEGV). - */ + /* Restart scan, explained above. */ goto restart_scan; } } diff --git a/linux-user/signal.c b/linux-user/signal.c index 4dafc2c3a2..c68b4e6c20 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -1382,6 +1382,11 @@ void process_pending_signals(CPUArchState *cpu_env) } handle_pending_signal(cpu_env, sig, &ts->sync_signal); + /* + * Restart scan from the beginning, as handle_pending_signal + * might have resulted in a new synchronous signal (eg SIGSEGV). + */ + goto restart_scan; } for (sig = 1; sig <= TARGET_NSIG; sig++) { @@ -1392,9 +1397,7 @@ void process_pending_signals(CPUArchState *cpu_env) (!sigismember(blocked_set, target_to_host_signal_table[sig]))) { handle_pending_signal(cpu_env, sig, &ts->sigtab[sig - 1]); - /* Restart scan from the beginning, as handle_pending_signal - * might have resulted in a new synchronous signal (eg SIGSEGV). - */ + /* Restart scan, explained above. */ goto restart_scan; } } -- 2.47.3
