From: Peter Maydell <peter.maydell@linaro.org>
Date: Fri, 22 Jul 2016 12:41:52 +0000 (+0100)
Subject: linux-user: Handle brk() attempts with very large sizes
X-Git-Tag: v2.7.0-rc2~15^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ef4330c23bb47b97a859dbdbae1c784fd2ca402f;p=thirdparty%2Fqemu.git

linux-user: Handle brk() attempts with very large sizes

In do_brk(), we were inadvertently truncating the size
of a requested brk() from the guest by putting it into an
'int' variable. This meant that we would incorrectly report
success back to the guest rather than a failed allocation,
typically resulting in the guest then segfaulting. Use
abi_ulong instead.

This fixes a crash in the '31370.cc' test in the gcc libstdc++ test
suite (the test case starts by trying to allocate a very large
size and reduces the size until the allocation succeeds).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
---

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index df6f2a9d0f0..833f853200e 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -839,7 +839,7 @@ void target_set_brk(abi_ulong new_brk)
 abi_long do_brk(abi_ulong new_brk)
 {
     abi_long mapped_addr;
-    int	new_alloc_size;
+    abi_ulong new_alloc_size;
 
     DEBUGF_BRK("do_brk(" TARGET_ABI_FMT_lx ") -> ", new_brk);