[patch 09/13] syslets: x86, mark async unsafe syscalls

[Ingo Molnar]

From: Ingo Molnar <[EMAIL PROTECTED]>

mark clone() and fork() as not available for async execution.
Both need an intact user context beneath them to work.

Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Arjan van de Ven <[EMAIL PROTECTED]>
---
 arch/i386/kernel/ioport.c  |    6 ++++++
 arch/i386/kernel/ldt.c     |    3 +++
 arch/i386/kernel/process.c |    6 ++++++
 arch/i386/kernel/vm86.c    |    6 ++++++
 4 files changed, 21 insertions(+)

Index: linux/arch/i386/kernel/ioport.c
===================================================================
--- linux.orig/arch/i386/kernel/ioport.c
+++ linux/arch/i386/kernel/ioport.c
@@ -62,6 +62,9 @@ asmlinkage long sys_ioperm(unsigned long
        struct tss_struct * tss;
        unsigned long *bitmap;
 
+       if (async_syscall(current))
+               return -ENOSYS;
+
        if ((from + num <= from) || (from + num > IO_BITMAP_BITS))
                return -EINVAL;
        if (turn_on && !capable(CAP_SYS_RAWIO))
@@ -139,6 +142,9 @@ asmlinkage long sys_iopl(unsigned long u
        unsigned int old = (regs->eflags >> 12) & 3;
        struct thread_struct *t = &current->thread;
 
+       if (async_syscall(current))
+               return -ENOSYS;
+
        if (level > 3)
                return -EINVAL;
        /* Trying to gain more privileges? */
Index: linux/arch/i386/kernel/ldt.c
===================================================================
--- linux.orig/arch/i386/kernel/ldt.c
+++ linux/arch/i386/kernel/ldt.c
@@ -233,6 +233,9 @@ asmlinkage int sys_modify_ldt(int func, 
 {
        int ret = -ENOSYS;
 
+       if (async_syscall(current))
+               return -ENOSYS;
+
        switch (func) {
        case 0:
                ret = read_ldt(ptr, bytecount);
Index: linux/arch/i386/kernel/process.c
===================================================================
--- linux.orig/arch/i386/kernel/process.c
+++ linux/arch/i386/kernel/process.c
@@ -731,6 +731,9 @@ struct task_struct fastcall * __switch_t
 
 asmlinkage int sys_fork(struct pt_regs regs)
 {
+       if (async_syscall(current))
+               return -ENOSYS;
+
        return do_fork(SIGCHLD, regs.esp, &regs, 0, NULL, NULL);
 }
 
@@ -740,6 +743,9 @@ asmlinkage int sys_clone(struct pt_regs 
        unsigned long newsp;
        int __user *parent_tidptr, *child_tidptr;
 
+       if (async_syscall(current))
+               return -ENOSYS;
+
        clone_flags = regs.ebx;
        newsp = regs.ecx;
        parent_tidptr = (int __user *)regs.edx;
Index: linux/arch/i386/kernel/vm86.c
===================================================================
--- linux.orig/arch/i386/kernel/vm86.c
+++ linux/arch/i386/kernel/vm86.c
@@ -208,6 +208,9 @@ asmlinkage int sys_vm86old(struct pt_reg
        struct task_struct *tsk;
        int tmp, ret = -EPERM;
 
+       if (async_syscall(current))
+               return -ENOSYS;
+
        tsk = current;
        if (tsk->thread.saved_esp0)
                goto out;
@@ -238,6 +241,9 @@ asmlinkage int sys_vm86(struct pt_regs r
        int tmp, ret;
        struct vm86plus_struct __user *v86;
 
+       if (async_syscall(current))
+               return -ENOSYS;
+
        tsk = current;
        switch (regs.ebx) {
                case VM86_REQUEST_IRQ:
-
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