ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP

User mode linux is the last user of the PT_DTRACE flag. Using the flag to indicate single stepping is a little confusing and worse changing tsk->ptrace without locking could potentionally cause problems. So use a thread info flag with a better name instead of flag in tsk->ptrace. Remove the definition PT_DTRACE as uml is the last user.

Eric W. Biederman committed 4 years ago

Commit c200e4b1 parent e71ba126 files · +10 −9Browse files

Unified · Split

6 files

arch/um/include/asm/thread_info.h +2 −0
arch/um/kernel/exec.c +1 −1
arch/um/kernel/process.c +1 −1
arch/um/kernel/ptrace.c +4 −4
arch/um/kernel/signal.c +2 −2
include/linux/ptrace.h +0 −1

arch/um/include/asm/thread_info.h+2−0

@@ -60,6 +60,7 @@ static inline struct thread_info *current_thread_info(void) · 59 unmodified lines
60	60	#define TIF_RESTORE_SIGMASK 7
61	61	#define TIF_NOTIFY_RESUME 8
62	62	#define TIF_SECCOMP 9 /* secure computing */
	63	+#define TIF_SINGLESTEP 10 /* single stepping userspace */
63	64
64	65	#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
65	66	#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
@@ -68,5 +69,6 @@ static inline struct thread_info *current_thread_info(void) · 2 unmodified lines
68	69	#define _TIF_MEMDIE (1 << TIF_MEMDIE)
69	70	#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
70	71	#define _TIF_SECCOMP (1 << TIF_SECCOMP)
	72	+#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
71	73
72	74	#endif

arch/um/kernel/exec.c+1−1

@@ -43,7 +43,7 @@ void start_thread(struct pt_regs *regs, unsigned long eip, unsigned long esp) · 42 unmodified lines
43	43	{
44	44	PT_REGS_IP(regs) = eip;
45	45	PT_REGS_SP(regs) = esp;
46		− current->ptrace &= ~PT_DTRACE;
	46	+ clear_thread_flag(TIF_SINGLESTEP);
47	47	#ifdef SUBARCH_EXECVE1
48	48	SUBARCH_EXECVE1(regs->regs);
49	49	#endif

arch/um/kernel/process.c+1−1

@@ -335,7 +335,7 @@ int singlestepping(void * t) · 334 unmodified lines
335	335	{
336	336	struct task_struct *task = t ? t : current;
337	337
338		− if (!(task->ptrace & PT_DTRACE))
	338	+ if (!test_thread_flag(TIF_SINGLESTEP))
339	339	return 0;
340	340
341	341	if (task->thread.singlestep_syscall)

arch/um/kernel/ptrace.c+4−4

@@ -11,7 +11,7 @@ · 10 unmodified lines
11	11
12	12	void user_enable_single_step(struct task_struct *child)
13	13	{
14		− child->ptrace \|= PT_DTRACE;
	14	+ set_tsk_thread_flag(child, TIF_SINGLESTEP);
15	15	child->thread.singlestep_syscall = 0;
16	16
17	17	#ifdef SUBARCH_SET_SINGLESTEPPING
@@ -21,7 +21,7 @@ void user_enable_single_step(struct task_struct *child) · 3 unmodified lines
21	21
22	22	void user_disable_single_step(struct task_struct *child)
23	23	{
24		− child->ptrace &= ~PT_DTRACE;
	24	+ clear_tsk_thread_flag(child, TIF_SINGLESTEP);
25	25	child->thread.singlestep_syscall = 0;
26	26
27	27	#ifdef SUBARCH_SET_SINGLESTEPPING
@@ -120,7 +120,7 @@ static void send_sigtrap(struct uml_pt_regs *regs, int error_code) · 92 unmodified lines
120	120	}
121	121
122	122	/*
123		− * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
	123	+ * XXX Check TIF_SINGLESTEP for singlestepping check and
124	124	* PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
125	125	*/
126	126	int syscall_trace_enter(struct pt_regs *regs)
@@ -144,7 +144,7 @@ void syscall_trace_leave(struct pt_regs *regs) · 17 unmodified lines
144	144	audit_syscall_exit(regs);
145	145
146	146	/* Fake a debug trap */
147		− if (ptraced & PT_DTRACE)
	147	+ if (test_thread_flag(TIF_SINGLESTEP))
148	148	send_sigtrap(&regs->regs, 0);
149	149
150	150	if (!test_thread_flag(TIF_SYSCALL_TRACE))

arch/um/kernel/signal.c+2−2

@@ -53,7 +53,7 @@ static void handle_signal(struct ksignal ksig, struct pt_regs regs) · 52 unmodified lines
53	53	unsigned long sp;
54	54	int err;
55	55
56		− if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
	56	+ if (test_thread_flag(TIF_SINGLESTEP) && (current->ptrace & PT_PTRACED))
57	57	singlestep = 1;
58	58
59	59	/* Did we come from a system call? */
@@ -128,7 +128,7 @@ void do_signal(struct pt_regs *regs) · 68 unmodified lines
128	128	* on the host. The tracing thread will check this flag and
129	129	* PTRACE_SYSCALL if necessary.
130	130	*/
131		− if (current->ptrace & PT_DTRACE)
	131	+ if (test_thread_flag(TIF_SINGLESTEP))
132	132	current->thread.singlestep_syscall =
133	133	is_syscall(PT_REGS_IP(&current->thread.regs));
134	134

include/linux/ptrace.h+0−1

@@ -30,7 +30,6 @@ extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr, · 29 unmodified lines
30	30
31	31	#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
32	32	#define PT_PTRACED 0x00000001
33		−#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
34	33
35	34	#define PT_OPT_FLAG_SHIFT 3
36	35	/* PT_TRACE_* event enable flags */