[PATCH 2/2] utrace: ptrace cooperation

From: Roland McGrath
Date: Mon Aug 25 2008 - 20:26:07 EST

This adds the CONFIG_UTRACE_PTRACE option under CONFIG_UTRACE.
When set, parts of ptrace are replaced so it uses the utrace
facilities for noticing events, stopping and resuming threads.

This makes ptrace play nicely with other utrace-based things
tracing the same threads. It also makes all ptrace uses rely on
some of the utrace code working right, even when you are not
using any other utrace-based things. So it's experimental and
not real well proven yet. But it's recommended if you enable
CONFIG_UTRACE and want to try new utrace things.

Signed-off-by: Roland McGrath <roland@xxxxxxxxxx>
---
include/linux/ptrace.h | 21 ++
include/linux/sched.h | 1 +
include/linux/tracehook.h | 4 +
init/Kconfig | 17 ++
kernel/ptrace.c | 604 ++++++++++++++++++++++++++++++++++++++++++++-
kernel/signal.c | 14 +-
kernel/utrace.c | 15 ++
7 files changed, 670 insertions(+), 6 deletions(-)

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index ea7416c..06eaace 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -121,6 +121,7 @@ static inline void ptrace_unlink(struct task_struct *child)
int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);

+#ifndef CONFIG_UTRACE_PTRACE
/**
* task_ptrace - return %PT_* flags that apply to a task
* @task: pointer to &task_struct in question
@@ -154,6 +155,26 @@ static inline int ptrace_event(int mask, int event, unsigned long message)
return 1;
}

+static inline void ptrace_utrace_exit(struct task_struct *task)
+{
+}
+
+#else /* CONFIG_UTRACE_PTRACE */
+
+static inline int task_ptrace(struct task_struct *task)
+{
+ return 0;
+}
+
+static inline int ptrace_event(int mask, int event, unsigned long message)
+{
+ return 0;
+}
+
+extern void ptrace_utrace_exit(struct task_struct *);
+
+#endif /* !CONFIG_UTRACE_PTRACE */
+
/**
* ptrace_init_task - initialize ptrace state for a new child
* @child: new child task
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c58f771..581c487 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1773,6 +1773,7 @@ extern int kill_pgrp(struct pid *pid, int sig, int priv);
extern int kill_pid(struct pid *pid, int sig, int priv);
extern int kill_proc_info(int, struct siginfo *, pid_t);
extern int do_notify_parent(struct task_struct *, int);
+extern void do_notify_parent_cldstop(struct task_struct *, int);
extern void force_sig(int, struct task_struct *);
extern void force_sig_specific(int, struct task_struct *);
extern int send_sig(int, struct task_struct *, int);
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 632a787..717a1c8 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -228,6 +228,8 @@ static inline void tracehook_report_exit(long *exit_code)
if (unlikely(task_utrace_flags(current) & UTRACE_EVENT(EXIT)))
utrace_report_exit(exit_code);
ptrace_event(PT_TRACE_EXIT, PTRACE_EVENT_EXIT, *exit_code);
+ if (unlikely(!list_empty(&current->ptraced)))
+ ptrace_utrace_exit(current);
}

/**
@@ -418,8 +420,10 @@ static inline void tracehook_signal_handler(int sig, siginfo_t *info,
{
if (task_utrace_flags(current))
utrace_signal_handler(current, stepping);
+#ifndef CONFIG_UTRACE_PTRACE
if (stepping)
ptrace_notify(SIGTRAP);
+#endif
}

/**
diff --git a/init/Kconfig b/init/Kconfig
index 89cbc74..a2b8ea8 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -908,6 +908,23 @@ menuconfig UTRACE
kernel interface exported to kernel modules, to track events in
user threads, extract and change user thread state.

+config UTRACE_PTRACE
+ bool "utrace-based ptrace (EXPERIMENTAL)"
+ default y if UTRACE
+ depends on UTRACE
+ help
+ This changes the implementation of ptrace() to cooperate with
+ the utrace facility. Without this option, using any utrace
+ facility on a task that anything also uses ptrace() on (i.e.
+ usual debuggers, strace, etc) can have confusing and unreliable
+ results. With this option, the ptrace() implementation is
+ changed to work via utrace facilities and the two cooperate well.
+
+ It's recommended to enable this if you are experimenting with
+ new modules that use utrace. But, disabling it makes sure that
+ using traditional ptrace() on tasks not touched by utrace will
+ not use any experimental new code that might be unreliable.
+
source "block/Kconfig"

config PREEMPT_NOTIFIERS
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 356699a..9734661 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -16,6 +16,7 @@
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/ptrace.h>
+#include <linux/utrace.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/audit.h>
@@ -38,6 +39,7 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
child->parent = new_parent;
}

+#ifndef CONFIG_UTRACE_PTRACE
/*
* Turn a tracing stop into a normal stop now, since with no tracer there
* would be no way to wake it up with SIGCONT or SIGKILL. If there was a
@@ -58,6 +60,54 @@ void ptrace_untrace(struct task_struct *child)
spin_unlock(&child->sighand->siglock);
}

+static void ptrace_finish(struct task_struct *child)
+{
+ if (task_is_traced(child))
+ ptrace_untrace(child);
+}
+
+static void ptrace_detach_task(struct task_struct *child)
+{
+ /* Architecture-specific hardware disable .. */
+ ptrace_disable(child);
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+}
+
+static void utrace_engine_put(struct utrace_attached_engine *engine)
+{
+}
+
+#else /* CONFIG_UTRACE_PTRACE */
+
+static const struct utrace_engine_ops ptrace_utrace_ops; /* forward decl */
+
+static void ptrace_detach_task(struct task_struct *child)
+{
+ struct utrace_attached_engine *engine;
+ engine = utrace_attach_task(child, UTRACE_ATTACH_MATCH_OPS,
+ &ptrace_utrace_ops, NULL);
+ if (likely(!IS_ERR(engine))) {
+ int ret = utrace_control(child, engine, UTRACE_DETACH);
+ WARN_ON(ret && ret != -ESRCH);
+ utrace_engine_put(engine);
+ }
+}
+
+void ptrace_utrace_exit(struct task_struct *task)
+{
+ struct task_struct *child;
+ read_lock(&tasklist_lock);
+ list_for_each_entry(child, &task->ptraced, ptrace_entry)
+ ptrace_detach_task(child);
+ read_unlock(&tasklist_lock);
+}
+
+static void ptrace_finish(struct task_struct *child)
+{
+}
+
+#endif /* !CONFIG_UTRACE_PTRACE */
+
/*
* unptrace a task: move it back to its original parent and
* remove it from the ptrace list.
@@ -72,10 +122,11 @@ void __ptrace_unlink(struct task_struct *child)
child->parent = child->real_parent;
list_del_init(&child->ptrace_entry);

- if (task_is_traced(child))
- ptrace_untrace(child);
+ ptrace_finish(child);
}

+#ifndef CONFIG_UTRACE_PTRACE
+
/*
* Check that we have indeed attached to the thing..
*/
@@ -113,6 +164,457 @@ int ptrace_check_attach(struct task_struct *child, int kill)
return ret;
}

+static struct utrace_attached_engine *ptrace_attach_utrace(
+ struct task_struct *task)
+{
+ return NULL;
+}
+
+static void ptrace_detach_utrace(struct task_struct *task,
+ struct utrace_attached_engine *engine)
+{
+}
+
+static int ptrace_update_utrace(struct task_struct *task,
+ struct utrace_attached_engine *engine)
+{
+ return 0;
+}
+
+#else /* CONFIG_UTRACE_PTRACE */
+
+static int ptrace_update_utrace(struct task_struct *task,
+ struct utrace_attached_engine *engine)
+{
+ unsigned long events;
+
+ /*
+ * We need this for resume handling.
+ */
+ events = UTRACE_EVENT(QUIESCE);
+
+ /*
+ * These events are always reported.
+ */
+ events |= UTRACE_EVENT(EXEC) | UTRACE_EVENT_SIGNAL_ALL;
+
+ /*
+ * We always have to examine clone events to check for CLONE_PTRACE.
+ */
+ events |= UTRACE_EVENT(CLONE);
+
+ /*
+ * PTRACE_SETOPTIONS can request more events.
+ */
+ if (task->ptrace & PT_TRACE_EXIT)
+ events |= UTRACE_EVENT(EXIT);
+
+ if (!engine) {
+ int ret;
+ engine = utrace_attach_task(task, UTRACE_ATTACH_MATCH_OPS,
+ &ptrace_utrace_ops, NULL);
+ if (IS_ERR(engine))
+ return -ESRCH;
+ ret = utrace_set_events(task, engine, events);
+ utrace_engine_put(engine);
+ return ret;
+ }
+
+ return utrace_set_events(task, engine, events);
+}
+
+static int ptrace_unsafe_exec(struct utrace_attached_engine *engine,
+ struct task_struct *task)
+{
+ if (task->ptrace & PT_PTRACE_CAP)
+ return LSM_UNSAFE_PTRACE_CAP;
+
+ return LSM_UNSAFE_PTRACE;
+}
+
+static struct task_struct *ptrace_tracer_task(
+ struct utrace_attached_engine *engine, struct task_struct *target)
+{
+ return target->parent;
+}
+
+static void ptrace_set_action(struct task_struct *task,
+ enum utrace_resume_action action,
+ enum utrace_syscall_action syscall)
+{
+ task->ptrace &= ~((UTRACE_SYSCALL_MASK | UTRACE_RESUME_MASK) << 16);
+ task->ptrace |= ((UTRACE_RESUME - action) | syscall) << 16;
+}
+
+static enum utrace_resume_action ptrace_resume_action(struct task_struct *task)
+{
+ return UTRACE_RESUME - ((task->ptrace >> 16) & UTRACE_RESUME_MASK);
+}
+
+static enum utrace_syscall_action ptrace_syscall_action(
+ struct task_struct *task)
+{
+ return (task->ptrace >> 16) & UTRACE_SYSCALL_MASK;
+}
+
+static u32 utrace_ptrace_report(u32 action, struct task_struct *task, int code)
+{
+ /*
+ * Special kludge magic in utrace.c (utrace_stop) sees this
+ * and calls do_notify_parent_cldstop() for us. This kludge
+ * is necessary to keep that wakeup after we enter TASK_TRACED.
+ */
+ ptrace_set_action(task, UTRACE_STOP, 0);
+
+ task->exit_code = code;
+
+ return action | UTRACE_STOP;
+}
+
+static u32 utrace_ptrace_event(struct task_struct *task,
+ int event, unsigned long msg)
+{
+ task->ptrace_message = msg;
+ return utrace_ptrace_report(0, task, (event << 8) | SIGTRAP);
+}
+
+static u32 ptrace_report_exec(enum utrace_resume_action action,
+ struct utrace_attached_engine *engine,
+ struct task_struct *task,
+ const struct linux_binfmt *fmt,
+ const struct linux_binprm *bprm,
+ struct pt_regs *regs)
+{
+ if (task->ptrace & PT_TRACE_EXEC)
+ return utrace_ptrace_event(task, PTRACE_EVENT_EXEC, 0);
+
+ /*
+ * Old-fashioned ptrace'd exec just posts a plain signal.
+ */
+ send_sig(SIGTRAP, task, 0);
+ return UTRACE_RESUME;
+}
+
+static u32 ptrace_report_exit(enum utrace_resume_action action,
+ struct utrace_attached_engine *engine,
+ struct task_struct *task,
+ long orig_code, long *code)
+{
+ return utrace_ptrace_event(task, PTRACE_EVENT_EXIT, *code);
+}
+
+#define PT_VFORKING PT_DTRACE /* reuse obsolete bit */
+
+static u32 ptrace_report_clone(enum utrace_resume_action action,
+ struct utrace_attached_engine *engine,
+ struct task_struct *parent,
+ unsigned long clone_flags,
+ struct task_struct *child)
+{
+ int event;
+ struct utrace_attached_engine *child_engine;
+
+ /*
+ * To simulate vfork-done tracing, we'll have to catch the
+ * parent's syscall-exit event for this vfork/clone system call.
+ * Since PTRACE_SETOPTIONS can enable PTRACE_O_TRACEVFORKDONE
+ * during the PTRACE_EVENT_VFORK stop, we must do this if either
+ * is enabled right now.
+ */
+ if ((clone_flags & CLONE_VFORK) &&
+ (parent->ptrace & (PT_TRACE_VFORK | PT_TRACE_VFORK_DONE))) {
+ if (!(engine->flags & UTRACE_EVENT(SYSCALL_EXIT))) {
+ int ret = utrace_set_events(parent, engine,
+ engine->flags |
+ UTRACE_EVENT(SYSCALL_EXIT));
+ WARN_ON(ret);
+ }
+ parent->ptrace |= PT_VFORKING;
+ }
+
+ if (clone_flags & CLONE_UNTRACED)
+ return UTRACE_RESUME;
+
+ event = 0;
+ if (clone_flags & CLONE_VFORK) {
+ if (parent->ptrace & PT_TRACE_VFORK)
+ event = PTRACE_EVENT_VFORK;
+ } else if ((clone_flags & CSIGNAL) != SIGCHLD) {
+ if (parent->ptrace & PT_TRACE_CLONE)
+ event = PTRACE_EVENT_CLONE;
+ } else if (parent->ptrace & PT_TRACE_FORK) {
+ event = PTRACE_EVENT_FORK;
+ }
+
+ if (!event)
+ return UTRACE_RESUME;
+
+ /*
+ * Any of these reports implies auto-attaching the new child.
+ */
+ child_engine = utrace_attach_task(child, UTRACE_ATTACH_CREATE |
+ UTRACE_ATTACH_EXCLUSIVE |
+ UTRACE_ATTACH_MATCH_OPS,
+ &ptrace_utrace_ops, NULL);
+ if (unlikely(IS_ERR(child_engine))) {
+ WARN_ON(1); /* XXX */
+ } else {
+ /* XXX already set by old ptrace code
+ task_lock(child);
+ child->ptrace = parent->ptrace;
+ child->parent = parent->parent;
+ task_unlock(child);
+ */
+ ptrace_update_utrace(child, child_engine);
+ utrace_engine_put(child_engine);
+ }
+
+ return utrace_ptrace_event(parent, event, child->pid);
+}
+
+
+static u32 ptrace_report_syscall(u32 action, struct task_struct *task)
+{
+ int code = SIGTRAP;
+ if (task->ptrace & PT_TRACESYSGOOD)
+ code |= 0x80;
+ return utrace_ptrace_report(action, task, code);
+}
+
+static u32 ptrace_report_syscall_entry(u32 action,
+ struct utrace_attached_engine *engine,
+ struct task_struct *task,
+ struct pt_regs *regs)
+{
+ /*
+ * If we're doing PTRACE_SYSEMU, just punt here and report
+ * at the exit stop instead.
+ */
+ if (ptrace_syscall_action(task))
+ return UTRACE_SYSCALL_ABORT | UTRACE_RESUME;
+
+ return ptrace_report_syscall(UTRACE_SYSCALL_RUN, task);
+}
+
+static u32 ptrace_report_syscall_exit(enum utrace_resume_action action,
+ struct utrace_attached_engine *engine,
+ struct task_struct *task,
+ struct pt_regs *regs)
+{
+ if (!(engine->flags & UTRACE_EVENT(SYSCALL_ENTRY))) {
+ /*
+ * We were not really using PTRACE_SYSCALL.
+ * SYSCALL_EXIT was only caught for vfork-done tracing.
+ */
+ int ret = utrace_set_events(
+ task, engine,
+ engine->flags & ~UTRACE_EVENT(SYSCALL_EXIT));
+ WARN_ON(ret);
+ WARN_ON(!(task->ptrace & PT_VFORKING));
+ task->ptrace &= ~PT_VFORKING;
+ return utrace_ptrace_event(task, PTRACE_EVENT_VFORK_DONE, 0);
+ }
+
+ if (task->ptrace & PT_VFORKING) {
+ /*
+ * If we're reporting vfork-done, we'll have to
+ * remember to report syscall-exit after that.
+ */
+ if (task->ptrace & PT_TRACE_VFORK_DONE)
+ return utrace_ptrace_event(task,
+ PTRACE_EVENT_VFORK_DONE, 0);
+ task->ptrace &= ~PT_VFORKING;
+ }
+
+ if (unlikely(ptrace_syscall_action(task)) &&
+ unlikely(ptrace_resume_action(task) == UTRACE_SINGLESTEP))
+ /*
+ * This is PTRACE_SYSEMU_SINGLESTEP.
+ * Kludge: Prevent arch code from sending a SIGTRAP
+ * after tracehook_report_syscall_exit() returns.
+ */
+ user_disable_single_step(task);
+
+ return ptrace_report_syscall(0, task);
+}
+
+static u32 ptrace_resumed(struct task_struct *task, struct pt_regs *regs,
+ siginfo_t *info, struct k_sigaction *return_ka)
+{
+ /*
+ * This is not a new signal, but just a notification we
+ * asked for. Either we're stopping after another report
+ * like exec or syscall, or we're resuming.
+ */
+ if (ptrace_resume_action(task) == UTRACE_STOP)
+ return UTRACE_SIGNAL_REPORT | UTRACE_STOP;
+
+ /*
+ * We're resuming. If there's no signal to deliver, just go.
+ * If we were given a signal, deliver it now.
+ */
+ task->last_siginfo = NULL;
+ if (!task->exit_code)
+ return UTRACE_SIGNAL_REPORT | ptrace_resume_action(task);
+
+ /* Update the siginfo structure if the signal has
+ changed. If the debugger wanted something
+ specific in the siginfo structure then it should
+ have updated *info via PTRACE_SETSIGINFO. */
+ if (task->exit_code != info->si_signo) {
+ info->si_signo = task->exit_code;
+ info->si_errno = 0;
+ info->si_code = SI_USER;
+ info->si_pid = task_pid_vnr(task->parent);
+ info->si_uid = task->parent->uid;
+ }
+
+ task->exit_code = 0;
+
+ spin_lock_irq(&task->sighand->siglock);
+ *return_ka = task->sighand->action[info->si_signo - 1];
+ spin_unlock_irq(&task->sighand->siglock);
+
+ return UTRACE_SIGNAL_DELIVER | ptrace_resume_action(task);
+}
+
+static u32 ptrace_report_signal(u32 action,
+ struct utrace_attached_engine *engine,
+ struct task_struct *task,
+ struct pt_regs *regs,
+ siginfo_t *info,
+ const struct k_sigaction *orig_ka,
+ struct k_sigaction *return_ka)
+{
+ /*
+ * Deal with a pending vfork-done event. We'll stop again now
+ * for the syscall-exit report that was replaced with vfork-done.
+ */
+ if (unlikely(task->ptrace & PT_VFORKING)) {
+ task->ptrace &= ~PT_VFORKING;
+ if ((engine->flags & UTRACE_EVENT(SYSCALL_ENTRY)) &&
+ utrace_signal_action(action) == UTRACE_SIGNAL_REPORT) {
+ /*
+ * Make sure we get another report on wakeup.
+ */
+ int x = utrace_control(task, engine, UTRACE_INTERRUPT);
+ WARN_ON(x);
+ return ptrace_report_syscall(UTRACE_SIGNAL_REPORT,
+ task);
+ }
+ }
+
+ switch (utrace_signal_action(action)) {
+ default:
+ break;
+ case UTRACE_SIGNAL_HANDLER:
+ /*
+ * A handler was set up. If we are stepping, pretend
+ * another SIGTRAP arrived.
+ */
+ if (ptrace_resume_action(task) == UTRACE_SINGLESTEP ||
+ ptrace_resume_action(task) == UTRACE_BLOCKSTEP) {
+ memset(info, 0, sizeof *info);
+ info->si_signo = SIGTRAP;
+ info->si_code = SIGTRAP;
+ info->si_pid = task_pid_vnr(task);
+ info->si_uid = task->uid;
+ break;
+ }
+ /* Fall through. */
+ case UTRACE_SIGNAL_REPORT:
+ return ptrace_resumed(task, regs, info, return_ka);
+ }
+
+ task->last_siginfo = info;
+ return utrace_ptrace_report(UTRACE_SIGNAL_IGN, task, info->si_signo);
+}
+
+static u32 ptrace_report_quiesce(u32 action,
+ struct utrace_attached_engine *engine,
+ struct task_struct *task,
+ unsigned long event)
+{
+ /*
+ * Make sure we deal with a pending vfork-done event (see above).
+ */
+ if (unlikely(task->ptrace & PT_VFORKING))
+ return UTRACE_INTERRUPT;
+
+ task->last_siginfo = NULL;
+ return ptrace_resume_action(task);
+}
+
+static const struct utrace_engine_ops ptrace_utrace_ops = {
+ .tracer_task = ptrace_tracer_task,
+ .unsafe_exec = ptrace_unsafe_exec,
+ .report_signal = ptrace_report_signal,
+ .report_quiesce = ptrace_report_quiesce,
+ .report_exec = ptrace_report_exec,
+ .report_exit = ptrace_report_exit,
+ .report_clone = ptrace_report_clone,
+ .report_syscall_entry = ptrace_report_syscall_entry,
+ .report_syscall_exit = ptrace_report_syscall_exit,
+};
+
+/*
+ * Detach the utrace engine.
+ */
+static void ptrace_detach_utrace(struct task_struct *task,
+ struct utrace_attached_engine *engine)
+{
+ int ret = utrace_control(task, engine, UTRACE_DETACH);
+ WARN_ON(ret && ret != -ESRCH);
+}
+
+/*
+ * Attach a utrace engine for ptrace and set up its event mask.
+ * Returns the engine pointer or an IS_ERR() pointer.
+ */
+static struct utrace_attached_engine *ptrace_attach_utrace(
+ struct task_struct *child)
+{
+ struct utrace_attached_engine *engine;
+ engine = utrace_attach_task(child, UTRACE_ATTACH_CREATE |
+ UTRACE_ATTACH_EXCLUSIVE |
+ UTRACE_ATTACH_MATCH_OPS,
+ &ptrace_utrace_ops, NULL);
+ if (IS_ERR(engine))
+ return engine;
+ if (likely(!ptrace_update_utrace(child, engine)))
+ return engine;
+ ptrace_detach_utrace(child, engine);
+ utrace_engine_put(engine);
+ return ERR_PTR(-ESRCH);
+}
+
+int ptrace_check_attach(struct task_struct *child, int kill)
+{
+ struct utrace_attached_engine *engine;
+ struct utrace_examiner exam;
+ int ret;
+
+ engine = utrace_attach_task(child, UTRACE_ATTACH_MATCH_OPS,
+ &ptrace_utrace_ops, NULL);
+ if (IS_ERR(engine))
+ return -ESRCH;
+
+ /*
+ * Make sure our engine has already stopped the child.
+ * Then wait for it to be off the CPU.
+ */
+ ret = 0;
+ if (utrace_control(child, engine, UTRACE_STOP) ||
+ utrace_prepare_examine(child, engine, &exam))
+ ret = -ESRCH;
+
+ utrace_engine_put(engine);
+
+ return ret;
+}
+
+#endif /* !CONFIG_UTRACE_PTRACE */
+
int __ptrace_may_access(struct task_struct *task, unsigned int mode)
{
/* May we inspect the given task?
@@ -156,6 +658,7 @@ int ptrace_attach(struct task_struct *task)
{
int retval;
unsigned long flags;
+ struct utrace_attached_engine *engine;

audit_ptrace(task);

@@ -163,6 +666,13 @@ int ptrace_attach(struct task_struct *task)
if (same_thread_group(task, current))
goto out;

+ engine = ptrace_attach_utrace(task);
+ if (unlikely(IS_ERR(engine))) {
+ if (PTR_ERR(engine) == -ESRCH)
+ retval = -ESRCH;
+ goto out;
+ }
+
repeat:
/*
* Nasty, nasty.
@@ -202,6 +712,11 @@ repeat:
bad:
write_unlock_irqrestore(&tasklist_lock, flags);
task_unlock(task);
+ if (!IS_ERR(engine)) {
+ if (retval)
+ ptrace_detach_utrace(task, engine);
+ utrace_engine_put(engine);
+ }
out:
return retval;
}
@@ -221,9 +736,7 @@ int ptrace_detach(struct task_struct *child, unsigned int data)
if (!valid_signal(data))
return -EIO;

- /* Architecture-specific hardware disable .. */
- ptrace_disable(child);
- clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+ ptrace_detach_task(child);

write_lock_irq(&tasklist_lock);
/* protect against de_thread()->release_task() */
@@ -309,6 +822,8 @@ static int ptrace_setoptions(struct task_struct *child, long data)
if (data & PTRACE_O_TRACEEXIT)
child->ptrace |= PT_TRACE_EXIT;

+ ptrace_update_utrace(child, NULL);
+
return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
}

@@ -367,6 +882,7 @@ static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
#define is_sysemu_singlestep(request) 0
#endif

+#ifndef CONFIG_UTRACE_PTRACE
static int ptrace_resume(struct task_struct *child, long request, long data)
{
if (!valid_signal(data))
@@ -401,6 +917,76 @@ static int ptrace_resume(struct task_struct *child, long request, long data)

return 0;
}
+#else /* CONFIG_UTRACE_PTRACE */
+static int ptrace_resume(struct task_struct *child, long request, long data)
+{
+ struct utrace_attached_engine *engine;
+ enum utrace_resume_action action;
+ enum utrace_syscall_action syscall;
+ int ret = 0;
+
+ if (!valid_signal(data))
+ return -EIO;
+
+ engine = utrace_attach_task(child, UTRACE_ATTACH_MATCH_OPS,
+ &ptrace_utrace_ops, NULL);
+ if (IS_ERR(engine))
+ return -ESRCH;
+
+ syscall = UTRACE_SYSCALL_RUN;
+#ifdef PTRACE_SYSEMU
+ if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
+ syscall = UTRACE_SYSCALL_ABORT;
+#endif
+
+ if (syscall != UTRACE_SYSCALL_RUN || request == PTRACE_SYSCALL) {
+ if (!(engine->flags & UTRACE_EVENT_SYSCALL) &&
+ utrace_set_events(child, engine,
+ engine->flags | UTRACE_EVENT_SYSCALL))
+ ret = -ESRCH;
+ } else if (engine->flags & UTRACE_EVENT(SYSCALL_ENTRY)) {
+ if (utrace_set_events(child, engine,
+ engine->flags & ~UTRACE_EVENT_SYSCALL))
+ ret = -ESRCH;
+ }
+
+ action = UTRACE_RESUME;
+ if (is_singleblock(request)) {
+ if (unlikely(!arch_has_block_step()))
+ ret = -EIO;
+ action = UTRACE_BLOCKSTEP;
+ } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
+ if (unlikely(!arch_has_single_step()))
+ ret = -EIO;
+ action = UTRACE_SINGLESTEP;
+ }
+
+ if (!ret) {
+ child->exit_code = data;
+
+ ptrace_set_action(child, action, syscall);
+
+ if (task_is_stopped(child)) {
+ spin_lock_irq(&child->sighand->siglock);
+ child->signal->flags &= ~SIGNAL_STOP_STOPPED;
+ spin_unlock_irq(&child->sighand->siglock);
+ }
+
+ /*
+ * To resume with a signal we must hit ptrace_report_signal.
+ */
+ if (data)
+ action = UTRACE_INTERRUPT;
+
+ if (utrace_control(child, engine, action))
+ ret = -ESRCH;
+ }
+
+ utrace_engine_put(engine);
+
+ return ret;
+}
+#endif /* !CONFIG_UTRACE_PTRACE */

int ptrace_request(struct task_struct *child, long request,
long addr, long data)
@@ -480,6 +1066,11 @@ int ptrace_request(struct task_struct *child, long request,
int ptrace_traceme(void)
{
int ret = -EPERM;
+ struct utrace_attached_engine *engine;
+
+ engine = ptrace_attach_utrace(current);
+ if (unlikely(IS_ERR(engine)))
+ return ret;

/*
* Are we already being traced?
@@ -513,6 +1104,9 @@ repeat:
write_unlock_irqrestore(&tasklist_lock, flags);
}
task_unlock(current);
+ if (ret)
+ ptrace_detach_utrace(current, engine);
+ utrace_engine_put(engine);
return ret;
}

diff --git a/kernel/signal.c b/kernel/signal.c
index e661b01..1effefc 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1415,7 +1415,7 @@ int do_notify_parent(struct task_struct *tsk, int sig)
return ret;
}

-static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
+void do_notify_parent_cldstop(struct task_struct *tsk, int why)
{
struct siginfo info;
unsigned long flags;
@@ -1470,6 +1470,8 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
spin_unlock_irqrestore(&sighand->siglock, flags);
}

+#ifndef CONFIG_UTRACE_PTRACE
+
static inline int may_ptrace_stop(void)
{
if (!likely(current->ptrace & PT_PTRACED))
@@ -1602,6 +1604,8 @@ void ptrace_notify(int exit_code)
spin_unlock_irq(&current->sighand->siglock);
}

+#endif /* !CONFIG_UTRACE_PTRACE */
+
static void
finish_stop(int stop_count)
{
@@ -1679,6 +1683,7 @@ static int do_signal_stop(int signr)
return 1;
}

+#ifndef CONFIG_UTRACE_PTRACE
static int ptrace_signal(int signr, siginfo_t *info,
struct pt_regs *regs, void *cookie)
{
@@ -1717,6 +1722,13 @@ static int ptrace_signal(int signr, siginfo_t *info,

return signr;
}
+#else
+static int ptrace_signal(int signr, siginfo_t *info,
+ struct pt_regs *regs, void *cookie)
+{
+ return signr;
+}
+#endif

int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
struct pt_regs *regs, void *cookie)
diff --git a/kernel/utrace.c b/kernel/utrace.c
index 918e7cf..aad2181 100644
--- a/kernel/utrace.c
+++ b/kernel/utrace.c
@@ -501,6 +501,21 @@ static bool utrace_stop(struct task_struct *task, struct utrace *utrace)
spin_unlock_irq(&task->sighand->siglock);
spin_unlock(&utrace->lock);

+#ifdef CONFIG_UTRACE_PTRACE
+ /*
+ * If ptrace is among the reasons for this stop, do its
+ * notification now. This could not just be done in
+ * ptrace's own event report callbacks because it has to
+ * be done after we are in TASK_TRACED. This makes the
+ * synchronization with ptrace_do_wait() work right.
+ */
+ if ((task->ptrace >> 16) == UTRACE_RESUME - UTRACE_STOP) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(task, CLD_TRAPPED);
+ read_unlock(&tasklist_lock);
+ }
+#endif
+
schedule();

/*
--
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