[xen staging] libxl: stop libxl_domain_info() consuming massive amounts of stack

[patchbot@xxxxxxx]

commit 2c4b1a7efb15292c0360f305b64581ac135ab8f2
Author:     Paul Durrant <pdurrant@xxxxxxxxxx>
AuthorDate: Thu May 28 16:13:30 2020 +0100
Commit:     Wei Liu <wl@xxxxxxx>
CommitDate: Tue Jun 2 11:57:01 2020 +0000

    libxl: stop libxl_domain_info() consuming massive amounts of stack
    
    Currently an array of 1024 xc_domaininfo_t is declared on stack. That alone
    consumes ~112k. Since libxl_domain_info() creates a new gc this patch simply
    uses it to allocate the array instead.
    
    Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
    Reviewed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
 tools/libxl/libxl_domain.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/libxl/libxl_domain.c b/tools/libxl/libxl_domain.c
index c08af308fa..39f08a6519 100644
--- a/tools/libxl/libxl_domain.c
+++ b/tools/libxl/libxl_domain.c
@@ -314,11 +314,13 @@ libxl_dominfo * libxl_list_domain(libxl_ctx *ctx, int 
*nb_domain_out)
 {
     libxl_dominfo *ptr = NULL;
     int i, ret;
-    xc_domaininfo_t info[1024];
+    xc_domaininfo_t *info;
     int size = 0;
     uint32_t domid = 0;
     GC_INIT(ctx);
 
+    GCNEW_ARRAY(info, 1024);
+
     while ((ret = xc_domain_getinfolist(ctx->xch, domid, 1024, info)) > 0) {
         ptr = libxl__realloc(NOGC, ptr, (size + ret) * sizeof(libxl_dominfo));
         for (i = 0; i < ret; i++) {
--
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