The commit is pushed to "branch-rh7-3.10.0-514.16.1.vz7.32.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.16.1.vz7.32.5
------>
commit 83201328d6bc00f946429ca97515e40218aaaf9e
Author: Dmitry Safonov <[email protected]>
Date: Wed May 31 16:00:01 2017 +0400
ms/x86/mm: Make mmap(MAP_32BIT) work correctly
mmap(MAP_32BIT) is broken due to the dependency on the TIF_ADDR32 thread
flag.
For 64bit applications MAP_32BIT will force legacy bottom-up allocations and
the 1GB address space restriction even if the application issued a compat
syscall, which should not be subject of these restrictions.
For 32bit applications, which issue 64bit syscalls the newly introduced
mmap base separation into 64-bit and compat bases changed the behaviour
because now a 64-bit mapping is returned, but due to the TIF_ADDR32
dependency MAP_32BIT is ignored. Before the separation a 32-bit mapping was
returned, so the MAP_32BIT handling was irrelevant.
Replace the check for TIF_ADDR32 with a check for the compat syscall. That
solves both the 64-bit issuing a compat syscall and the 32-bit issuing a
64-bit syscall problems.
[ tglx: Massaged changelog ]
Signed-off-by: Dmitry Safonov <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Andy Lutomirski <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
[peeked from ms commit 3e6ef9c80946]
Signed-off-by: Dmitry Safonov <[email protected]>
---
arch/x86/kernel/sys_x86_64.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 7c64989..ffe8b89 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -114,7 +114,7 @@ static unsigned long get_mmap_base(int is_legacy)
static void find_start_end(unsigned long flags, unsigned long *begin,
unsigned long *end)
{
- if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) {
+ if (!in_compat_syscall() && (flags & MAP_32BIT)) {
unsigned long new_begin;
/* This is usually used needed to map code in small
model, so it needs to be in the first 31bit. Limit
@@ -193,7 +193,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const
unsigned long addr0,
return addr;
/* for MAP_32BIT mappings we force the legacy mmap base */
- if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
+ if (!in_compat_syscall() && (flags & MAP_32BIT))
goto bottomup;
/* requesting a specific address */
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