From: Marc-André Lureau <marcandre.lureau@redhat.com>
Date: Tue, 29 Mar 2016 11:20:51 +0000 (+0200)
Subject: memory: fix segv on qemu_ram_free(block=0x0)
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=85bc2a15121e8bcd9f15eb75794a1eacca9d84bd;p=qemu.git

memory: fix segv on qemu_ram_free(block=0x0)

Since f1060c55bf1377b4, the pointer is directly passed to
qemu_ram_free(). However, on initialization failure, it may be called
with a NULL pointer. Return immediately in this case.

This fixes a SEGV when memory initialization failed, for example
permission denied on open backing store /dev/hugepages, with -object
memory-backend-file,mem-path=/dev/hugepages.

Program received signal SIGSEGV, Segmentation fault.
0x00005555556e67e7 in qemu_ram_free (block=0x0) at /home/elmarco/src/qemu/exec.c:1775

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1459250451-29984-1-git-send-email-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/exec.c b/exec.c
index f46e596818..c4f9036184 100644
--- a/exec.c
+++ b/exec.c
@@ -1773,6 +1773,10 @@ static void reclaim_ramblock(RAMBlock *block)
 
 void qemu_ram_free(RAMBlock *block)
 {
+    if (!block) {
+        return;
+    }
+
     qemu_mutex_lock_ramlist();
     QLIST_REMOVE_RCU(block, next);
     ram_list.mru_block = NULL;