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authorCédric VINCENT <cedric.vincent@st.com>2011-08-26 10:56:50 +0200
committerRiku Voipio <riku.voipio@linaro.org>2011-09-09 10:45:13 +0300
commit70afc343c75ecc8895b9308ee6a15fcc7a3b0f3e (patch)
treefb8cb07baeedbbadaffbe205b8e2c634937ec36e /linux-user
parent07ff2c4475df77e38a31d50ee7f3932631806c15 (diff)
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linux-user: Fix initialization of the heap contents when allocating new pages
Technically the new mmapped pages are already initialized to zero since they are anonymous, however we have to take care with the contents that come from the remaining part of the previous page: it may contains garbage data due to a previous heap usage (grown then shrunken). This patch completes commit 55f08c84. The problem could be reproduced when emulating the build process of Perl 5.12.3 on ARMedSlack 13.37: make[1]: Entering directory `/tmp/perl-5.12.3/cpan/Compress-Raw-Bzip2' cc -c -I. -fno-strict-aliasing -pipe -fstack-protector \ -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 \ -O2 -DVERSION=\"2.024\" -DXS_VERSION=\"2.024\" -fPIC "-I../.." \ -DBZ_NO_STDIO decompress.c decompress.c: In function 'BZ2_decompress': decompress.c:621:1: internal compiler error: Segmentation fault Signed-off-by: Riku Voipio <riku.voipio@linaro.org> Signed-off-by: Laurent ALFONSI <laurent.alfonsi@st.com> Signed-off-by: Cédric VINCENT <cedric.vincent@st.com>
Diffstat (limited to 'linux-user')
-rw-r--r--linux-user/syscall.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 6bdf4e6..ae08c9e 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -797,6 +797,15 @@ abi_long do_brk(abi_ulong new_brk)
MAP_ANON|MAP_PRIVATE, 0, 0));
if (mapped_addr == brk_page) {
+ /* Heap contents are initialized to zero, as for anonymous
+ * mapped pages. Technically the new pages are already
+ * initialized to zero since they *are* anonymous mapped
+ * pages, however we have to take care with the contents that
+ * come from the remaining part of the previous page: it may
+ * contains garbage data due to a previous heap usage (grown
+ * then shrunken). */
+ memset(g2h(target_brk), 0, brk_page - target_brk);
+
target_brk = new_brk;
brk_page = HOST_PAGE_ALIGN(target_brk);
DEBUGF_BRK("%#010x (mapped_addr == brk_page)\n", target_brk);