From: Alex Bradbury Date: Tue, 2 Dec 2025 23:05:55 +0000 (+0000) Subject: contrib/plugins/hotblocks: Fix off by one error in iteration of sorted blocks X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1c1e45fcd66269f8a6dbd97fd7b8267d8f6f58af;p=thirdparty%2Fqemu.git contrib/plugins/hotblocks: Fix off by one error in iteration of sorted blocks The logic to iterate over the hottest blocks will never reach the last item in the list, as it checks `it->next != NULL` before entering the loop. It's hard to trigger this off-by-one error with the default limit=20, but it is a bug and is problematic if that default is changed to something larger. Signed-off-by: Alex Bradbury Reviewed-by: Pierrick Bouvier Link: https://lore.kernel.org/qemu-devel/f1ba2e57c6126472c0c8310774009f2455efc370.1753857212.git.asb@igalia.com Signed-off-by: Pierrick Bouvier --- diff --git a/contrib/plugins/hotblocks.c b/contrib/plugins/hotblocks.c index d3dd23ed9f..cf4d6b8c36 100644 --- a/contrib/plugins/hotblocks.c +++ b/contrib/plugins/hotblocks.c @@ -82,10 +82,9 @@ static void plugin_exit(qemu_plugin_id_t id, void *p) sorted_counts = g_list_sort_with_data(counts, cmp_exec_count, NULL); if (sorted_counts) { - it = sorted_counts; g_string_append_printf(report, "pc, tcount, icount, ecount\n"); - for (i = 0; i < limit && it->next; i++, it = it->next) { + for (i = 0, it = sorted_counts; i < limit && it; i++, it = it->next) { ExecCount *rec = (ExecCount *) it->data; g_string_append_printf( report, "0x%016"PRIx64", %d, %ld, %"PRId64"\n",