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-rw-r--r--arch/x86/kernel/process.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 43cbfc84153a..5e1f38179f49 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -156,7 +156,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
#endif
/* Kernel thread ? */
- if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
+ if (unlikely(p->flags & PF_KTHREAD)) {
memset(childregs, 0, sizeof(struct pt_regs));
kthread_frame_init(frame, sp, arg);
return 0;
@@ -172,6 +172,23 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
task_user_gs(p) = get_user_gs(current_pt_regs());
#endif
+ if (unlikely(p->flags & PF_IO_WORKER)) {
+ /*
+ * An IO thread is a user space thread, but it doesn't
+ * return to ret_after_fork().
+ *
+ * In order to indicate that to tools like gdb,
+ * we reset the stack and instruction pointers.
+ *
+ * It does the same kernel frame setup to return to a kernel
+ * function that a kernel thread does.
+ */
+ childregs->sp = 0;
+ childregs->ip = 0;
+ kthread_frame_init(frame, sp, arg);
+ return 0;
+ }
+
/* Set a new TLS for the child thread? */
if (clone_flags & CLONE_SETTLS)
ret = set_new_tls(p, tls);