From 655ed67c2a248cf0a887229d8492d6ddc0518545 Mon Sep 17 00:00:00 2001 From: Timothy E Baldwin Date: Fri, 27 May 2016 15:51:53 +0100 Subject: linux-user: Queue synchronous signals separately If a synchronous signal and an asynchronous signal arrive near simultaneously, and the signal number of the asynchronous signal is lower than that of the synchronous signal the the handler for the asynchronous would be called first, and then the handler for the synchronous signal would be called within or after the first handler with an incorrect context. This is fixed by queuing synchronous signals separately. Note that this does risk delaying a asynchronous signal until the synchronous signal handler returns rather than handling the signal on another thread, but this seems unlikely to cause problems for real guest programs and is unavoidable unless we could guarantee to roll back and reexecute whatever guest instruction caused the synchronous signal (which would be a bit odd if we've already logged its execution, for instance, and would require careful analysis of all guest CPUs to check it was possible in all cases). Signed-off-by: Timothy Edward Baldwin Message-id: 1441497448-32489-24-git-send-email-T.E.Baldwin99@members.leeds.ac.uk [PMM: added a comment] Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell Signed-off-by: Riku Voipio --- linux-user/qemu.h | 1 + 1 file changed, 1 insertion(+) (limited to 'linux-user/qemu.h') diff --git a/linux-user/qemu.h b/linux-user/qemu.h index b201f9042c..6bd7b3223a 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -119,6 +119,7 @@ typedef struct TaskState { struct image_info *info; struct linux_binprm *bprm; + struct emulated_sigtable sync_signal; struct emulated_sigtable sigtab[TARGET_NSIG]; /* This thread's signal mask, as requested by the guest program. * The actual signal mask of this thread may differ: -- cgit v1.2.3