From f6a6bc735015e7db9e20650f05496fed9a7e77ec Mon Sep 17 00:00:00 2001 From: Liam Merwick Date: Fri, 23 May 2025 16:01:34 +0000 Subject: [PATCH] hw/xen: Fix trace_xs_node_read() params MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When the '--enable-trace-backends=syslog' build option is configured, the following compilation error is encountered. In file included from /usr/include/sys/syslog.h:207, from /usr/include/syslog.h:1, from ./trace/trace-hw_xen.h:224, from ../hw/xen/trace.h:1, from ../hw/xen/xen-bus-helper.c:13: In function ‘syslog’, inlined from ‘_nocheck__trace_xs_node_read’ at ../hw/xen/trace-events:41:9, inlined from ‘trace_xs_node_read’ at trace/trace-hw_xen.h:903:9, inlined from ‘xs_node_read’ at ../hw/xen/xen-bus-helper.c:154:5: /usr/include/bits/syslog.h:45:3: error: ‘%s’ directive argument is null [-Werror=format-overflow=] 45 | __syslog_chk (__pri, __USE_FORTIFY_LEVEL - 1, __fmt, __va_arg_pack ()); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Add a check that 'value' is not null before passing it to trace_xs_node_read(). Fixes: e6cdeee95990 ("hw/xen: Add xs_node_read() helper function") Signed-off-by: Liam Merwick Reviewed-by: Philippe Mathieu-Daudé Acked-by: Anthony PERARD Acked-by: David Woodhouse Message-ID: <20250523160134.218997-1-liam.merwick@oracle.com> Signed-off-by: Anthony PERARD --- hw/xen/xen-bus-helper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/xen/xen-bus-helper.c b/hw/xen/xen-bus-helper.c index 288fad422b..1087a585cc 100644 --- a/hw/xen/xen-bus-helper.c +++ b/hw/xen/xen-bus-helper.c @@ -151,7 +151,7 @@ char *xs_node_read(struct qemu_xs_handle *h, xs_transaction_t tid, va_end(ap); value = qemu_xen_xs_read(h, tid, path, len); - trace_xs_node_read(path, value); + trace_xs_node_read(path, value ? value : ""); if (!value) { error_setg_errno(errp, errno, "failed to read from '%s'", path); }