On Mon, May 20, 2013, at 14:42, Satoru Takeuchi wrote:
> At Sun, 19 May 2013 11:37:27 -0700,
> Greg Kroah-Hartman wrote:
> >
> > On Fri, May 17, 2013 at 04:51:33PM -0700, Greg Kroah-Hartman wrote:
> > > On Fri, May 17, 2013 at 11:49:30PM +0100, Al Viro wrote:
> > > > On Fri, May 17, 2013 at 02:35:42PM -0700, Greg Kroah-Hartman wrote:
> > > > > 3.9-stable review patch. If anyone has any objections, please let me know.
> > > >
> > > > This is seriously wrong. For 3.9 you _need_ asmlinkage_protect() in that
> > > > thing; by the time when that went into the tree, mainline already had
> > > > it generated automatically by SYSCALL_DEFINE, so there was no point in
> > > > that part of patch - the switch to SYSCALL_DEFINE alone did the job.
> > > > For 3.9 it's very much needed; as the matter of fact, in 3.9 that commit
> > > > is a no-op in the form you took.
> > > >
> > > > We can grab all prereqs into 3.9-stable (there's not that much of those),
> > > > but that would be much more intrusive than the variant adding explicit
> > > > asmlinkage_protect() in those two syscalls.
> > >
> > > Ok, Alexander was saying something was off here.
> > >
> > > Can someone send me just the needed patch to get this working properly,
> > > and I will be glad to drop this one from the 3.9.x tree.
> >
> > I've now dropped this, and will release without it.
>
> Here is the backported patch. It calls asmlinkage_protect() properly and is
> as similar to upstream patch as possible.
Thanks, Satoru!
This patch looks good for v3.9 stable...
Greetings,
Alexander
> It can be applied to 3.9.3 and can be built successfully.
>
> Satoru
>
> ---
> From: Satoru Takeuchi <satoru.takeuchi@xxxxxxxxx>
> Date: Mon, 20 May 2013 21:32:20 +0900
> Subject: x86, vm86: fix VM86 syscalls: use SYSCALL_DEFINEx(...)
>
> commit 5522ddb3fc0dfd4a503c8278eafd88c9f2d3fada upstream.
>
> Commit 49cb25e9290 x86: 'get rid of pt_regs argument in vm86/vm86old'
> got rid of the pt_regs stub for sys_vm86old and sys_vm86. The functions
> were, however, not changed to use the calling convention for syscalls.
>
> Reported-and-tested-by: Hans de Bruin <jmdebruin@xxxxxxxxx>
> Signed-off-by: Alexander van Heukelum <heukelum@xxxxxxxxxxx>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/syscalls.h | 4 ++--
> arch/x86/kernel/vm86_32.c | 11 ++++++-----
> 2 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h
> index 6cf0a9c..5a0be0a 100644
> --- a/arch/x86/include/asm/syscalls.h
> +++ b/arch/x86/include/asm/syscalls.h
> @@ -37,8 +37,8 @@ asmlinkage int sys_get_thread_area(struct user_desc __user *);
> unsigned long sys_sigreturn(void);
>
> /* kernel/vm86_32.c */
> -int sys_vm86old(struct vm86_struct __user *);
> -int sys_vm86(unsigned long, unsigned long);
> +asmlinkage long sys_vm86old(struct vm86_struct __user *);
> +asmlinkage long sys_vm86(unsigned long, unsigned long);
>
> #else /* CONFIG_X86_32 */
>
> diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
> index 1cf5766..3dbdd9c 100644
> --- a/arch/x86/kernel/vm86_32.c
> +++ b/arch/x86/kernel/vm86_32.c
> @@ -33,6 +33,7 @@
> #include <linux/capability.h>
> #include <linux/errno.h>
> #include <linux/interrupt.h>
> +#include <linux/syscalls.h>
> #include <linux/sched.h>
> #include <linux/kernel.h>
> #include <linux/signal.h>
> @@ -48,7 +49,6 @@
> #include <asm/io.h>
> #include <asm/tlbflush.h>
> #include <asm/irq.h>
> -#include <asm/syscalls.h>
>
> /*
> * Known problems:
> @@ -202,17 +202,16 @@ out:
> static int do_vm86_irq_handling(int subfunction, int irqnumber);
> static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk);
>
> -int sys_vm86old(struct vm86_struct __user *v86)
> +SYSCALL_DEFINE1(vm86old, struct vm86_struct __user *, v86)
> {
> struct kernel_vm86_struct info; /* declare this _on top_,
> * this avoids wasting of stack space.
> * This remains on the stack until we
> * return to 32 bit user space.
> */
> - struct task_struct *tsk;
> + struct task_struct *tsk = current;
> int tmp, ret = -EPERM;
>
> - tsk = current;
> if (tsk->thread.saved_sp0)
> goto out;
> tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs,
> @@ -227,11 +226,12 @@ int sys_vm86old(struct vm86_struct __user *v86)
> do_sys_vm86(&info, tsk);
> ret = 0; /* we never return here */
> out:
> + asmlinkage_protect(1, ret, v86);
> return ret;
> }
>
>
> -int sys_vm86(unsigned long cmd, unsigned long arg)
> +SYSCALL_DEFINE2(vm86, unsigned long, cmd, unsigned long, arg)
> {
> struct kernel_vm86_struct info; /* declare this _on top_,
> * this avoids wasting of stack space.
> @@ -278,6 +278,7 @@ int sys_vm86(unsigned long cmd, unsigned long arg)
> do_sys_vm86(&info, tsk);
> ret = 0; /* we never return here */
> out:
> + asmlinkage_protect(2, ret, cmd, arg);
> return ret;
> }
>
> --
> 1.7.10.4
>
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