Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 02/46] s390/compat: fix mmap compat system calls | Date | Sun, 19 Aug 2012 20:58:38 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.5-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens <heiko.carstens@de.ibm.com>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/s390/kernel/compat_linux.c | 2 -- 1 file changed, 2 deletions(-)
--- a/arch/s390/kernel/compat_linux.c +++ b/arch/s390/kernel/compat_linux.c @@ -622,7 +622,6 @@ asmlinkage unsigned long old32_mmap(stru 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); } @@ -633,7 +632,6 @@ asmlinkage long sys32_mmap2(struct mmap_ 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); }
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