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authorJeff Dike <jdike@addtoit.com>2007-03-07 23:41:26 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-03-08 10:38:22 -0500
commit44f5c4ced6ddee2f5f2e45fa45b93370245d85bd (patch)
tree0ba80acf1666a3fe82a3cb09ae0052b58c1d2af1 /arch/um/sys-x86_64
parent9bebff6ca5871e07b665cdaf71028ea21eb0bf0e (diff)
[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>
Diffstat (limited to 'arch/um/sys-x86_64')
-rw-r--r--arch/um/sys-x86_64/syscalls.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/um/sys-x86_64/syscalls.c b/arch/um/sys-x86_64/syscalls.c
index 01b91f9fa789..b3f6350cac44 100644
--- a/arch/um/sys-x86_64/syscalls.c
+++ b/arch/um/sys-x86_64/syscalls.c
@@ -103,6 +103,9 @@ long arch_prctl_skas(struct task_struct *task, int code,
103 103
104 switch(code){ 104 switch(code){
105 case ARCH_SET_FS: 105 case ARCH_SET_FS:
106 current->thread.arch.fs = (unsigned long) ptr;
107 save_registers(pid, &current->thread.regs.regs);
108 break;
106 case ARCH_SET_GS: 109 case ARCH_SET_GS:
107 save_registers(pid, &current->thread.regs.regs); 110 save_registers(pid, &current->thread.regs.regs);
108 break; 111 break;
@@ -140,9 +143,8 @@ long sys_clone(unsigned long clone_flags, unsigned long newsp,
140 143
141void arch_switch_to_skas(struct task_struct *from, struct task_struct *to) 144void arch_switch_to_skas(struct task_struct *from, struct task_struct *to)
142{ 145{
143 if(to->thread.arch.fs == 0) 146 if((to->thread.arch.fs == 0) || (to->mm == NULL))
144 return; 147 return;
145 148
146 arch_prctl_skas(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs); 149 arch_prctl_skas(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
147} 150}
148