From 2d02fc0e933a7d4a30e8bb7c665d898d00ac5e00 Mon Sep 17 00:00:00 2001

From: Igor Mammedov <imammedo@redhat.com>

Date: Fri, 23 Nov 2018 11:58:47 +0100

Subject: [PATCH 14/34] memory: cleanup side effects of

 memory_region_init_foo() on failure

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RH-Author: Igor Mammedov <imammedo@redhat.com>

Message-id: <1542974327-165907-1-git-send-email-imammedo@redhat.com>

Patchwork-id: 83127

O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH v2] memory: cleanup side effects of memory_region_init_foo() on failure

Bugzilla: 1585155

RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1585155

Brew: http://brewweb.devel.redhat.com/brew/taskinfo?taskID=19261375

if MemoryRegion intialization fails it's left in semi-initialized state,

where it's size is not 0 and attached as child to owner object.

And this leds to crash in following use-case:

    (monitor) object_add memory-backend-file,id=mem1,size=99999G,mem-path=/tmp/foo,discard-data=yes

    memory.c:2083: memory_region_get_ram_ptr: Assertion `mr->ram_block' failed

    Aborted (core dumped)

it happens due to assumption that memory region is intialized when

   memory_region_size() != 0

and therefore it's ok to access it in

   file_backend_unparent()

      if (memory_region_size() != 0)

          memory_region_get_ram_ptr()

which happens when object_add fails and unparents failed backend making

file_backend_unparent() access invalid memory region.

Fix it by making sure that memory_region_init_foo() APIs cleanup externally

visible side effects on failure (like set size to 0 and unparenting object)

Signed-off-by: Igor Mammedov <imammedo@redhat.com>

Message-Id: <1536064777-42312-1-git-send-email-imammedo@redhat.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

(cherry picked from commit 1cd3d492624da399d66c4c3e6a5eabb8f96bb0a2)

Signed-off-by: Igor Mammedov <imammedo@redhat.com>

---

v2:

  - clean backport since dependency has been backported and merged as

      (commit 754dd8f2 memory, exec: switch file ram allocation functions to 'flags' parameters)

 enter the commit message for your changes. Lines starting

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 memory.c | 48 ++++++++++++++++++++++++++++++++++++++++++------

 1 file changed, 42 insertions(+), 6 deletions(-)

diff --git a/memory.c b/memory.c

index 7b47f53..4974f97 100644

--- a/memory.c

+++ b/memory.c

@@ -1519,12 +1519,18 @@ void memory_region_init_ram_shared_nomigrate(MemoryRegion *mr,

                                              bool share,

                                              Error **errp)

 {

+    Error *err = NULL;

     memory_region_init(mr, owner, name, size);

     mr->ram = true;

     mr->terminates = true;

     mr->destructor = memory_region_destructor_ram;

-    mr->ram_block = qemu_ram_alloc(size, share, mr, errp);

+    mr->ram_block = qemu_ram_alloc(size, share, mr, &err;;

     mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;

+    if (err) {

+        mr->size = int128_zero();

+        object_unparent(OBJECT(mr));

+        error_propagate(errp, err);

+    }

 }

 void memory_region_init_resizeable_ram(MemoryRegion *mr,

@@ -1537,13 +1543,19 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr,

                                                        void *host),

                                        Error **errp)

 {

+    Error *err = NULL;

     memory_region_init(mr, owner, name, size);

     mr->ram = true;

     mr->terminates = true;

     mr->destructor = memory_region_destructor_ram;

     mr->ram_block = qemu_ram_alloc_resizeable(size, max_size, resized,

-                                              mr, errp);

+                                              mr, &err;;

     mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;

+    if (err) {

+        mr->size = int128_zero();

+        object_unparent(OBJECT(mr));

+        error_propagate(errp, err);

+    }

 }

 #ifdef __linux__

@@ -1556,13 +1568,19 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,

                                       const char *path,

                                       Error **errp)

 {

+    Error *err = NULL;

     memory_region_init(mr, owner, name, size);

     mr->ram = true;

     mr->terminates = true;

     mr->destructor = memory_region_destructor_ram;

     mr->align = align;

-    mr->ram_block = qemu_ram_alloc_from_file(size, mr, ram_flags, path, errp);

+    mr->ram_block = qemu_ram_alloc_from_file(size, mr, ram_flags, path, &err;;

     mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;

+    if (err) {

+        mr->size = int128_zero();

+        object_unparent(OBJECT(mr));

+        error_propagate(errp, err);

+    }

 }

 void memory_region_init_ram_from_fd(MemoryRegion *mr,

@@ -1573,14 +1591,20 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,

                                     int fd,

                                     Error **errp)

 {

+    Error *err = NULL;

     memory_region_init(mr, owner, name, size);

     mr->ram = true;

     mr->terminates = true;

     mr->destructor = memory_region_destructor_ram;

     mr->ram_block = qemu_ram_alloc_from_fd(size, mr,

                                            share ? RAM_SHARED : 0,

-                                           fd, errp);

+                                           fd, &err;;

     mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;

+    if (err) {

+        mr->size = int128_zero();

+        object_unparent(OBJECT(mr));

+        error_propagate(errp, err);

+    }

 }

 #endif

@@ -1631,13 +1655,19 @@ void memory_region_init_rom_nomigrate(MemoryRegion *mr,

                                       uint64_t size,

                                       Error **errp)

 {

+    Error *err = NULL;

     memory_region_init(mr, owner, name, size);

     mr->ram = true;

     mr->readonly = true;

     mr->terminates = true;

     mr->destructor = memory_region_destructor_ram;

-    mr->ram_block = qemu_ram_alloc(size, false, mr, errp);

+    mr->ram_block = qemu_ram_alloc(size, false, mr, &err;;

     mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;

+    if (err) {

+        mr->size = int128_zero();

+        object_unparent(OBJECT(mr));

+        error_propagate(errp, err);

+    }

 }

 void memory_region_init_rom_device_nomigrate(MemoryRegion *mr,

@@ -1648,6 +1678,7 @@ void memory_region_init_rom_device_nomigrate(MemoryRegion *mr,

                                              uint64_t size,

                                              Error **errp)

 {

+    Error *err = NULL;

     assert(ops);

     memory_region_init(mr, owner, name, size);

     mr->ops = ops;

@@ -1655,7 +1686,12 @@ void memory_region_init_rom_device_nomigrate(MemoryRegion *mr,

     mr->terminates = true;

     mr->rom_device = true;

     mr->destructor = memory_region_destructor_ram;

-    mr->ram_block = qemu_ram_alloc(size, false,  mr, errp);

+    mr->ram_block = qemu_ram_alloc(size, false,  mr, &err;;

+    if (err) {

+        mr->size = int128_zero();

+        object_unparent(OBJECT(mr));

+        error_propagate(errp, err);

+    }

 }

 void memory_region_init_iommu(void *_iommu_mr,

-- 

1.8.3.1