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-rw-r--r--arch/x86/include/asm/ptrace.h16
-rw-r--r--include/linux/ptrace.h3
2 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 14fd6fd75a1..6205f0c434d 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -231,6 +231,22 @@ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
#define ARCH_HAS_USER_SINGLE_STEP_INFO
+/*
+ * When hitting ptrace_stop(), we cannot return using SYSRET because
+ * that does not restore the full CPU state, only a minimal set. The
+ * ptracer can change arbitrary register values, which is usually okay
+ * because the usual ptrace stops run off the signal delivery path which
+ * forces IRET; however, ptrace_event() stops happen in arbitrary places
+ * in the kernel and don't force IRET path.
+ *
+ * So force IRET path after a ptrace stop.
+ */
+#define arch_ptrace_stop_needed(code, info) \
+({ \
+ set_thread_flag(TIF_NOTIFY_RESUME); \
+ false; \
+})
+
struct user_desc;
extern int do_get_thread_area(struct task_struct *p, int idx,
struct user_desc __user *info);
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 077904c8b70..cc79eff4a1a 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -334,6 +334,9 @@ static inline void user_single_step_siginfo(struct task_struct *tsk,
* calling arch_ptrace_stop() when it would be superfluous. For example,
* if the thread has not been back to user mode since the last stop, the
* thread state might indicate that nothing needs to be done.
+ *
+ * This is guaranteed to be invoked once before a task stops for ptrace and
+ * may include arch-specific operations necessary prior to a ptrace stop.
*/
#define arch_ptrace_stop_needed(code, info) (0)
#endif