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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2012-08-08 09:32:20 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-08-19 18:15:35 +0100 |
| commit | b2ef34da747ee998a41e6b081987480777b7c23a (patch) | |
| tree | 32bf873fcb7770b1cc8be1706e4bb0f8bb6aab56 /arch/s390 | |
| parent | 0b3160dde9f41e7bbc125ab8d00a6e367e956854 (diff) | |
| download | lwn-b2ef34da747ee998a41e6b081987480777b7c23a.tar.gz lwn-b2ef34da747ee998a41e6b081987480777b7c23a.zip | |
s390/compat: fix mmap compat system calls
commit e85871218513c54f7dfdb6009043cb638f2fecbe upstream.
The native 31 bit and the compat behaviour for the mmap system calls differ:
In native 31 bit mode the passed in address for the mmap system call will be
unmodified passed to sys_mmap_pgoff().
In compat mode however the passed in address will be modified with
compat_ptr() which masks out the most significant bit.
The result is that in native 31 bit mode each mmap request (with MAP_FIXED)
will fail where the most significat bit is set, while in compat mode it
may succeed.
This odd behaviour was introduced with d3815898 "[S390] mmap: add missing
compat_ptr conversion to both mmap compat syscalls".
To restore a consistent behaviour accross native and compat mode this
patch functionally reverts the above mentioned commit.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kernel/compat_linux.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c index 84a982898448..38c66455b927 100644 --- a/arch/s390/kernel/compat_linux.c +++ b/arch/s390/kernel/compat_linux.c @@ -615,7 +615,6 @@ asmlinkage unsigned long old32_mmap(struct mmap_arg_struct_emu31 __user *arg) return -EFAULT; if (a.offset & ~PAGE_MASK) return -EINVAL; - a.addr = (unsigned long) compat_ptr(a.addr); return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset >> PAGE_SHIFT); } @@ -626,7 +625,6 @@ asmlinkage long sys32_mmap2(struct mmap_arg_struct_emu31 __user *arg) if (copy_from_user(&a, arg, sizeof(a))) return -EFAULT; - a.addr = (unsigned long) compat_ptr(a.addr); return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset); } |