[qemu-xen staging] linux-user: fix the errno value in print_syscall_err()

[patchbot@xxxxxxx]

commit 6733d57035d1c4a67070b8d737334c28e5c63bc6
Author:     Laurent Vivier <laurent@xxxxxxxxx>
AuthorDate: Wed Jul 8 17:24:34 2020 +0200
Commit:     Laurent Vivier <laurent@xxxxxxxxx>
CommitDate: Tue Jul 14 09:29:14 2020 +0200

    linux-user: fix the errno value in print_syscall_err()
    
    errno of the target is returned as a negative value by the syscall,
    not in the host errno variable.
    
    The emulation of the target syscall can return an error while the
    host doesn't set an errno value. Target errnos and host errnos can
    also differ in some cases.
    
    Fixes: c84be71f6854 ("linux-user: Extend strace support to enable argument 
printing after syscall execution")
    Cc: Filip.Bozuta@xxxxxxxxxx
    Signed-off-by: Laurent Vivier <laurent@xxxxxxxxx>
    Reviewed-by: Richard Henderson <richard.henderson@xxxxxxxxxx>
    Reviewed-by: Philippe Mathieu-Daudé <f4bug@xxxxxxxxx>
    Reviewed-by: Filip Bozuta <Filip.Bozuta@xxxxxxxxxx>
    Message-Id: <20200708152435.706070-2-laurent@xxxxxxxxx>
---
 linux-user/strace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/linux-user/strace.c b/linux-user/strace.c
index 39554d9039..7769f53bd5 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -731,7 +731,7 @@ print_syscall_err(abi_long ret)
 
     qemu_log(" = ");
     if (ret < 0) {
-        qemu_log("-1 errno=%d", errno);
+        qemu_log("-1 errno=%d", (int)-ret);
         errstr = target_strerror(-ret);
         if (errstr) {
             qemu_log(" (%s)", errstr);
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#staging