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[Qemu-devel] [PATCH 3/3] block/qcow2-bitmap: Don't take address of field
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH 3/3] block/qcow2-bitmap: Don't take address of fields in packed structs |
Date: |
Tue, 9 Oct 2018 18:25:01 +0100 |
Taking the address of a field in a packed struct is a bad idea, because
it might not be actually aligned enough for that pointer type (and
thus cause a crash on dereference on some host architectures). Newer
versions of clang warn about this. Avoid the bug by not using the
"modify in place" byte swapping functions.
There are a few places where the in-place swap function is
used on something other than a packed struct field; we convert
those anyway, for consistency.
This patch was produced with the following spatch script:
@@
expression E;
@@
-be16_to_cpus(&E);
+E = be16_to_cpu(E);
@@
expression E;
@@
-be32_to_cpus(&E);
+E = be32_to_cpu(E);
@@
expression E;
@@
-be64_to_cpus(&E);
+E = be64_to_cpu(E);
@@
expression E;
@@
-cpu_to_be16s(&E);
+E = cpu_to_be16(E);
@@
expression E;
@@
-cpu_to_be32s(&E);
+E = cpu_to_be32(E);
@@
expression E;
@@
-cpu_to_be64s(&E);
+E = cpu_to_be64(E);
Signed-off-by: Peter Maydell <address@hidden>
---
block/qcow2-bitmap.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index ba978ad2aac..74f7638e03c 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -118,7 +118,7 @@ static inline void bitmap_table_to_be(uint64_t
*bitmap_table, size_t size)
size_t i;
for (i = 0; i < size; ++i) {
- cpu_to_be64s(&bitmap_table[i]);
+ bitmap_table[i] = cpu_to_be64(bitmap_table[i]);
}
}
@@ -231,7 +231,7 @@ static int bitmap_table_load(BlockDriverState *bs,
Qcow2BitmapTable *tb,
}
for (i = 0; i < tb->size; ++i) {
- be64_to_cpus(&table[i]);
+ table[i] = be64_to_cpu(table[i]);
ret = check_table_entry(table[i], s->cluster_size);
if (ret < 0) {
goto fail;
@@ -394,20 +394,20 @@ fail:
static inline void bitmap_dir_entry_to_cpu(Qcow2BitmapDirEntry *entry)
{
- be64_to_cpus(&entry->bitmap_table_offset);
- be32_to_cpus(&entry->bitmap_table_size);
- be32_to_cpus(&entry->flags);
- be16_to_cpus(&entry->name_size);
- be32_to_cpus(&entry->extra_data_size);
+ entry->bitmap_table_offset = be64_to_cpu(entry->bitmap_table_offset);
+ entry->bitmap_table_size = be32_to_cpu(entry->bitmap_table_size);
+ entry->flags = be32_to_cpu(entry->flags);
+ entry->name_size = be16_to_cpu(entry->name_size);
+ entry->extra_data_size = be32_to_cpu(entry->extra_data_size);
}
static inline void bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry)
{
- cpu_to_be64s(&entry->bitmap_table_offset);
- cpu_to_be32s(&entry->bitmap_table_size);
- cpu_to_be32s(&entry->flags);
- cpu_to_be16s(&entry->name_size);
- cpu_to_be32s(&entry->extra_data_size);
+ entry->bitmap_table_offset = cpu_to_be64(entry->bitmap_table_offset);
+ entry->bitmap_table_size = cpu_to_be32(entry->bitmap_table_size);
+ entry->flags = cpu_to_be32(entry->flags);
+ entry->name_size = cpu_to_be16(entry->name_size);
+ entry->extra_data_size = cpu_to_be32(entry->extra_data_size);
}
static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_size)
--
2.19.0
- [Qemu-devel] [PATCH 0/3] block/qcow*: Don't take address of fields in packed structs, Peter Maydell, 2018/10/09
- [Qemu-devel] [PATCH 2/3] block/qcow: Don't take address of fields in packed structs, Peter Maydell, 2018/10/09
- [Qemu-devel] [PATCH 3/3] block/qcow2-bitmap: Don't take address of fields in packed structs,
Peter Maydell <=
- [Qemu-devel] [PATCH 1/3] block/qcow2: Don't take address of fields in packed structs, Peter Maydell, 2018/10/09
- Re: [Qemu-devel] [PATCH 0/3] block/qcow*: Don't take address of fields in packed structs, Richard Henderson, 2018/10/09
- Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] block/qcow*: Don't take address of fields in packed structs, John Snow, 2018/10/09
- Re: [Qemu-devel] [PATCH 0/3] block/qcow*: Don't take address of fields in packed structs, Kevin Wolf, 2018/10/10