Patchwork [RFC,1/7] acpi: qemu_realloc() might return a different pointer

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Submitter Eduard - Gabriel Munteanu
Date March 30, 2010, 8:20 a.m.
Message ID <9b87085a250d0f70509687e4ab09336244734fad.1269936879.git.eduard.munteanu@linux360.ro>
Download mbox | patch
Permalink /patch/48969/
State New
Headers show

Comments

Eduard - Gabriel Munteanu - March 30, 2010, 8:20 a.m.
We mustn't assume qemu_realloc() returns the same pointer in
acpi_table_add(). Therefore, 'p' might be invalid if it's relative to
the old value of acpi_tables.

Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
---
 hw/acpi.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

Patch

diff --git a/hw/acpi.c b/hw/acpi.c
index d293127..7c4e8d3 100644
--- a/hw/acpi.c
+++ b/hw/acpi.c
@@ -857,7 +857,7 @@  int acpi_table_add(const char *t)
     char buf[1024], *p, *f;
     struct acpi_table_header acpi_hdr;
     unsigned long val;
-    size_t off;
+    size_t newlen, off;
 
     memset(&acpi_hdr, 0, sizeof(acpi_hdr));
   
@@ -938,9 +938,10 @@  int acpi_table_add(const char *t)
         acpi_tables_len = sizeof(uint16_t);
         acpi_tables = qemu_mallocz(acpi_tables_len);
     }
+    newlen = acpi_tables_len + sizeof(uint16_t) + acpi_hdr.length;
+    acpi_tables = qemu_realloc(acpi_tables, newlen);
     p = acpi_tables + acpi_tables_len;
-    acpi_tables_len += sizeof(uint16_t) + acpi_hdr.length;
-    acpi_tables = qemu_realloc(acpi_tables, acpi_tables_len);
+    acpi_tables_len = newlen;
 
     acpi_hdr.length = cpu_to_le32(acpi_hdr.length);
     *(uint16_t*)p = acpi_hdr.length;