diff options
| author | Roland McGrath <roland@redhat.com> | 2008-07-25 19:45:50 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-26 12:00:09 -0700 |
| commit | fa8e26ccd485216fc45c8c2dd1ec3b7ef1a0a2f8 (patch) | |
| tree | b6c3059593d7d185aaf7f5b69c363a48b18c5bb1 | |
| parent | 0d094efeb1e98010c6b99923f1eb7e17bf1e3a74 (diff) | |
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 <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/tracehook.h | 15 | ||||
| -rw-r--r-- | mm/nommu.c | 4 |
2 files changed, 17 insertions, 2 deletions
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 6468ca0fe69..e113e09b034 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -52,6 +52,21 @@ 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 4462b6a3fcb..5edccd9c921 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -22,7 +22,7 @@ #include <linux/pagemap.h> #include <linux/slab.h> #include <linux/vmalloc.h> -#include <linux/ptrace.h> +#include <linux/tracehook.h> #include <linux/blkdev.h> #include <linux/backing-dev.h> #include <linux/mount.h> @@ -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; |