From fa8e26ccd485216fc45c8c2dd1ec3b7ef1a0a2f8 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Fri, 25 Jul 2008 19:45:50 -0700 Subject: [PATCH] tracehook: tracehook_expect_breakpoints This adds tracehook_expect_breakpoints() as a formal hook for the nommu code to use for its, "Is text-poking likely?" check at mmap time. This names the actual semantics the code means to test, and documents it. Signed-off-by: Roland McGrath Cc: Oleg Nesterov Reviewed-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/tracehook.h | 15 +++++++++++++++ mm/nommu.c | 4 ++-- 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 6468ca0fe69b..e113e09b0341 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -51,6 +51,21 @@ #include struct linux_binprm; +/** + * tracehook_expect_breakpoints - guess if task memory might be touched + * @task: current task, making a new mapping + * + * Return nonzero if @task is expected to want breakpoint insertion in + * its memory at some point. A zero return is no guarantee it won't + * be done, but this is a hint that it's known to be likely. + * + * May be called with @task->mm->mmap_sem held for writing. + */ +static inline int tracehook_expect_breakpoints(struct task_struct *task) +{ + return (task_ptrace(task) & PT_PTRACED) != 0; +} + /** * tracehook_unsafe_exec - check for exec declared unsafe due to tracing * @task: current task doing exec diff --git a/mm/nommu.c b/mm/nommu.c index 4462b6a3fcb9..5edccd9c9218 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -22,7 +22,7 @@ #include #include #include -#include +#include #include #include #include @@ -745,7 +745,7 @@ static unsigned long determine_vm_flags(struct file *file, * it's being traced - otherwise breakpoints set in it may interfere * with another untraced process */ - if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED)) + if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current)) vm_flags &= ~VM_MAYSHARE; return vm_flags; -- 2.20.1