The patch titled
kill PT_ATTACHED
has been added to the -mm tree. Its filename is
kill-pt_attached.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: kill PT_ATTACHED
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Since the patch
"Fix ptrace_attach()/ptrace_traceme()/de_thread() race"
commit f5b40e363ad6041a96e3da32281d8faa191597b9
we set PT_ATTACHED and change child->parent "atomically" wrt task_list lock.
This means we can remove the checks like "PT_ATTACHED && ->parent != ptracer"
which were needed to catch the "ptrace attach is in progress" case. We can
also remove the flag itself since nobody else uses it.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/ptrace.h | 1 -
kernel/exit.c | 13 +------------
kernel/ptrace.c | 6 ++----
kernel/signal.c | 5 -----
4 files changed, 3 insertions(+), 22 deletions(-)
diff -puN include/linux/ptrace.h~kill-pt_attached include/linux/ptrace.h
--- a/include/linux/ptrace.h~kill-pt_attached
+++ a/include/linux/ptrace.h
@@ -67,7 +67,6 @@
#define PT_TRACE_EXEC 0x00000080
#define PT_TRACE_VFORK_DONE 0x00000100
#define PT_TRACE_EXIT 0x00000200
-#define PT_ATTACHED 0x00000400 /* parent != real_parent */
#define PT_TRACE_MASK 0x000003f4
diff -puN kernel/exit.c~kill-pt_attached kernel/exit.c
--- a/kernel/exit.c~kill-pt_attached
+++ a/kernel/exit.c
@@ -1511,18 +1511,7 @@ static int wait_task_continued(struct ta
static inline int my_ptrace_child(struct task_struct *p)
{
- if (!(p->ptrace & PT_PTRACED))
- return 0;
- if (!(p->ptrace & PT_ATTACHED))
- return 1;
- /*
- * This child was PTRACE_ATTACH'd. We should be seeing it only if
- * we are the attacher. If we are the real parent, this is a race
- * inside ptrace_attach. It is waiting for the tasklist_lock,
- * which we have to switch the parent links, but has already set
- * the flags in p->ptrace.
- */
- return (p->parent != p->real_parent);
+ return p->ptrace & PT_PTRACED;
}
static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
diff -puN kernel/ptrace.c~kill-pt_attached kernel/ptrace.c
--- a/kernel/ptrace.c~kill-pt_attached
+++ a/kernel/ptrace.c
@@ -100,8 +100,7 @@ int ptrace_check_attach(struct task_stru
*/
read_lock(&tasklist_lock);
if ((child->ptrace & PT_PTRACED) && child->parent == current &&
- (!(child->ptrace & PT_ATTACHED) || child->real_parent != current)
- && child->signal != NULL) {
+ child->signal != NULL) {
ret = 0;
spin_lock_irq(&child->sighand->siglock);
if (is_task_stopped(child))
@@ -200,8 +199,7 @@ repeat:
goto bad;
/* Go */
- task->ptrace |= PT_PTRACED | ((task->real_parent != current)
- ? PT_ATTACHED : 0);
+ task->ptrace |= PT_PTRACED;
if (capable(CAP_SYS_PTRACE))
task->ptrace |= PT_PTRACE_CAP;
diff -puN kernel/signal.c~kill-pt_attached kernel/signal.c
--- a/kernel/signal.c~kill-pt_attached
+++ a/kernel/signal.c
@@ -1577,11 +1577,6 @@ static inline int may_ptrace_stop(void)
{
if (!likely(current->ptrace & PT_PTRACED))
return 0;
-
- if (unlikely(current->parent == current->real_parent &&
- (current->ptrace & PT_ATTACHED)))
- return 0;
-
/*
* Are we in the middle of do_coredump?
* If so and our tracer is also part of the coredump stopping
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
wait_task_stopped-dont-use-task_pid_nr_ns-lockless.patch
proc-remove-races-from-proc_id_readdir.patch
wait_task_stopped-pass-correct-exit_code-to.patch
use-__set_task_state-for-traced-stopped-tasks.patch
add-task_wakekill.patch
do_wait-remove-one-else-if-branch.patch
proc-implement-proc_single_file_operations.patch
proc-rewrite-do_task_stat-to-correctly-handle-pid-namespaces.patch
proc-seqfile-convert-proc_pid_statm.patch
proc-proper-pidns-handling-for-proc-self.patch
proc-fix-the-threaded-proc-self.patch
kill-pt_attached.patch
kill-my_ptrace_child.patch
ptrace_check_attach-remove-unneeded-signal-=-null-check.patch
-
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