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Message-ID: <20210624092615.947779232@infradead.org>
Date: Thu, 24 Jun 2021 11:21:59 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: rjw@...ysocki.net, oleg@...hat.com, mingo@...nel.org,
vincent.guittot@...aro.org, dietmar.eggemann@....com,
rostedt@...dmis.org, mgorman@...e.de, Will Deacon <will@...nel.org>
Cc: linux-kernel@...r.kernel.org, peterz@...radead.org, tj@...nel.org,
linux-pm@...r.kernel.org
Subject: [PATCH v2 3/4] ptrace: Track __TASK_TRACED state in p->ptrace
Just like we can recover __TASK_STOPPED from p->jobctl, add some bits
to p->ptrace such that we can recover __TASK_TRACED.
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
include/linux/ptrace.h | 36 +++++++++++++++++++++---------------
include/linux/sched/signal.h | 6 ++----
kernel/ptrace.c | 25 ++++++++++++++++---------
kernel/signal.c | 1 +
4 files changed, 40 insertions(+), 28 deletions(-)
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -28,30 +28,36 @@ extern int ptrace_access_vm(struct task_
* flags. When the a task is stopped the ptracer owns task->ptrace.
*/
-#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
-#define PT_PTRACED 0x00000001
-#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
+#define PT_PTRACED 0x00000001 // 0x00000001
+#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */ // 0x00000002
#define PT_OPT_FLAG_SHIFT 3
/* PT_TRACE_* event enable flags */
#define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event)))
-#define PT_TRACESYSGOOD PT_EVENT_FLAG(0)
-#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
-#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
-#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
-#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
-#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
-#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
-#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP)
-#define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
-#define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
+#define PT_TRACESYSGOOD PT_EVENT_FLAG(0) // 0x00000008
+#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK) // 0x00000010
+#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK) // 0x00000020
+#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE) // 0x00000040
+#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC) // 0x00000080
+#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE) // 0x00000100
+#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT) // 0x00000200
+#define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP) // 0x00000400
+
+#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */// 0x00010000
+#define PT_STOPPED 0x00020000 // 0x00020000
+#define PT_STOPPED_FATAL 0x00040000 // 0x00040000
+
+#define PT_STOPPED_MASK (PT_STOPPED|PT_STOPPED_FATAL)
+
+#define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT) // 0x00800000
+#define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT) // 0x01000000
/* single stepping state bits (used on ARM and PA-RISC) */
#define PT_SINGLESTEP_BIT 31
-#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
+#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT) // 0x80000000
#define PT_BLOCKSTEP_BIT 30
-#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
+#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT) // 0x40000000
extern long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data);
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -422,10 +422,8 @@ static inline void signal_wake_up(struct
{
signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
}
-static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
-{
- signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
-}
+
+extern void ptrace_signal_wake_up(struct task_struct *t, bool resume);
void task_join_group_stop(struct task_struct *task);
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -64,6 +64,12 @@ int ptrace_access_vm(struct task_struct
return ret;
}
+void ptrace_signal_wake_up(struct task_struct *t, bool resume)
+{
+ if (resume)
+ t->ptrace &= ~PT_STOPPED_MASK;
+ signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
+}
void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
const struct cred *ptracer_cred)
@@ -197,6 +203,8 @@ static bool ptrace_freeze_traced(struct
spin_lock_irq(&task->sighand->siglock);
if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
!__fatal_signal_pending(task)) {
+ task->ptrace &= ~PT_STOPPED_MASK;
+ task->ptrace |= PT_STOPPED;
WRITE_ONCE(task->__state, __TASK_TRACED);
ret = true;
}
@@ -218,10 +226,13 @@ static void ptrace_unfreeze_traced(struc
*/
spin_lock_irq(&task->sighand->siglock);
if (READ_ONCE(task->__state) == __TASK_TRACED) {
- if (__fatal_signal_pending(task))
+ if (__fatal_signal_pending(task)) {
+ task->ptrace &= ~PT_STOPPED_MASK;
wake_up_state(task, __TASK_TRACED);
- else
+ } else {
+ task->ptrace |= PT_STOPPED_MASK;
WRITE_ONCE(task->__state, TASK_TRACED);
+ }
}
spin_unlock_irq(&task->sighand->siglock);
}
@@ -835,8 +846,6 @@ static long ptrace_get_rseq_configuratio
static int ptrace_resume(struct task_struct *child, long request,
unsigned long data)
{
- bool need_siglock;
-
if (!valid_signal(data))
return -EIO;
@@ -877,13 +886,11 @@ static int ptrace_resume(struct task_str
* status and clears the code too; this can't race with the tracee, it
* takes siglock after resume.
*/
- need_siglock = data && !thread_group_empty(current);
- if (need_siglock)
- spin_lock_irq(&child->sighand->siglock);
+ spin_lock_irq(&child->sighand->siglock);
child->exit_code = data;
+ child->ptrace &= ~PT_STOPPED_MASK;
wake_up_state(child, __TASK_TRACED);
- if (need_siglock)
- spin_unlock_irq(&child->sighand->siglock);
+ spin_unlock_irq(&child->sighand->siglock);
return 0;
}
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2195,6 +2195,7 @@ static void ptrace_stop(int exit_code, i
return;
}
+ current->ptrace |= PT_STOPPED_MASK;
set_special_state(TASK_TRACED);
/*
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