Commit 44f5c4ce authored Mar 07, 2007 by Jeff Dike Committed by Linus Torvalds Mar 08, 2007

[PATCH] uml: arch_prctl should set thread fs



In my previous x86_64 thread fix, I forgot to initialize thread.arch.fs in
arch_prctl.  A process calling arch_prctl to set %fs would lose it on the
next context switch.

It also turns out that you can switch to a process which is in the process
of exiting and which has lost its mm.  In this case, it's worse than
useless to try to call arch_prctl on the host process.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 9bebff6c

arch/um/sys-x86_64/syscalls.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -103,6 +103,9 @@ long arch_prctl_skas(struct task_struct *task, int code,

		switch(code){
		case ARCH_SET_FS:
		current->thread.arch.fs = (unsigned long) ptr;
		save_registers(pid, &current->thread.regs.regs);
		break;
		case ARCH_SET_GS:
		save_registers(pid, &current->thread.regs.regs);
		break;
		@@ -140,9 +143,8 @@ long sys_clone(unsigned long clone_flags, unsigned long newsp,

		void arch_switch_to_skas(struct task_struct from, struct task_struct to)
		{
		if(to->thread.arch.fs == 0)
		if((to->thread.arch.fs == 0) \|\| (to->mm == NULL))
		return;

		arch_prctl_skas(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
		}