From 9dc46386d89d83c73c41c2b19be83a73957c4393 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 12 Mar 2021 17:35:54 +0100 Subject: [PATCH] gnttab: work around "may be used uninitialized" warning Sadly I was wrong to suggest dropping vaddrs' initializer during review of v2 of the patch introducing this code. gcc 4.3 can't cope. Fixes: 52531c734ea1 ("xen/gnttab: Rework resource acquisition") Signed-off-by: Jan Beulich Acked-by: Andrew Cooper Release-Acked-by: Ian Jackson --- xen/common/grant_table.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c index f937c1d350..ab30e2e8cf 100644 --- a/xen/common/grant_table.c +++ b/xen/common/grant_table.c @@ -4026,7 +4026,7 @@ int gnttab_acquire_resource( struct grant_table *gt = d->grant_table; unsigned int i, final_frame; mfn_t tmp; - void **vaddrs; + void **vaddrs = NULL; int rc = -EINVAL; if ( !nr_frames ) @@ -4055,6 +4055,17 @@ int gnttab_acquire_resource( break; } + /* + * Some older toolchains can't spot that vaddrs won't remain uninitialized + * on non-error paths, and hence it needs setting to NULL at the top of the + * function. Leave some runtime safety. + */ + if ( !vaddrs ) + { + ASSERT_UNREACHABLE(); + rc = -ENODATA; + } + /* Any errors? Bad id, or from growing the table? */ if ( rc ) goto out; -- 2.30.2