d184d6eb1d
The fake SIGSTOP during attach has numerous problems. PTRACE_SEIZE
is already fine, but we have basically the same problems is SIGSTOP
is sent on auto-attach, the tracer can't know if this signal signal
should be cancelled or not.
Change ptrace_event() to set JOBCTL_TRAP_STOP if the new child is
PT_SEIZED, this triggers the PTRACE_EVENT_STOP report.
Thereafter a PT_SEIZED task can never report the bogus SIGSTOP.
Test-case:
#define PTRACE_SEIZE 0x4206
#define PTRACE_SEIZE_DEVEL 0x80000000
#define PTRACE_EVENT_STOP 7
#define WEVENT(s) ((s & 0xFF0000) >> 16)
int main(void)
{
int child, grand_child, status;
long message;
child = fork();
if (!child) {
kill(getpid(), SIGSTOP);
fork();
assert(0);
return 0x23;
}
assert(ptrace(PTRACE_SEIZE, child, 0,PTRACE_SEIZE_DEVEL) == 0);
assert(wait(&status) == child);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP);
assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACEFORK) == 0);
assert(ptrace(PTRACE_CONT, child, 0,0) == 0);
assert(waitpid(child, &status, 0) == child);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGTRAP);
assert(WEVENT(status) == PTRACE_EVENT_FORK);
assert(ptrace(PTRACE_GETEVENTMSG, child, 0, &message) == 0);
grand_child = message;
assert(waitpid(grand_child, &status, 0) == grand_child);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGTRAP);
assert(WEVENT(status) == PTRACE_EVENT_STOP);
kill(child, SIGKILL);
kill(grand_child, SIGKILL);
return 0;
}
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
408 lines
14 KiB
C
408 lines
14 KiB
C
#ifndef _LINUX_PTRACE_H
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#define _LINUX_PTRACE_H
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/* ptrace.h */
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/* structs and defines to help the user use the ptrace system call. */
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/* has the defines to get at the registers. */
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#define PTRACE_TRACEME 0
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#define PTRACE_PEEKTEXT 1
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#define PTRACE_PEEKDATA 2
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#define PTRACE_PEEKUSR 3
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#define PTRACE_POKETEXT 4
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#define PTRACE_POKEDATA 5
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#define PTRACE_POKEUSR 6
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#define PTRACE_CONT 7
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#define PTRACE_KILL 8
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#define PTRACE_SINGLESTEP 9
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#define PTRACE_ATTACH 16
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#define PTRACE_DETACH 17
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#define PTRACE_SYSCALL 24
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/* 0x4200-0x4300 are reserved for architecture-independent additions. */
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#define PTRACE_SETOPTIONS 0x4200
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#define PTRACE_GETEVENTMSG 0x4201
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#define PTRACE_GETSIGINFO 0x4202
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#define PTRACE_SETSIGINFO 0x4203
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/*
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* Generic ptrace interface that exports the architecture specific regsets
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* using the corresponding NT_* types (which are also used in the core dump).
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* Please note that the NT_PRSTATUS note type in a core dump contains a full
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* 'struct elf_prstatus'. But the user_regset for NT_PRSTATUS contains just the
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* elf_gregset_t that is the pr_reg field of 'struct elf_prstatus'. For all the
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* other user_regset flavors, the user_regset layout and the ELF core dump note
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* payload are exactly the same layout.
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*
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* This interface usage is as follows:
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* struct iovec iov = { buf, len};
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*
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* ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov);
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*
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* On the successful completion, iov.len will be updated by the kernel,
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* specifying how much the kernel has written/read to/from the user's iov.buf.
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*/
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#define PTRACE_GETREGSET 0x4204
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#define PTRACE_SETREGSET 0x4205
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#define PTRACE_SEIZE 0x4206
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#define PTRACE_INTERRUPT 0x4207
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#define PTRACE_LISTEN 0x4208
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/* flags in @data for PTRACE_SEIZE */
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#define PTRACE_SEIZE_DEVEL 0x80000000 /* temp flag for development */
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/* options set using PTRACE_SETOPTIONS */
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#define PTRACE_O_TRACESYSGOOD 0x00000001
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#define PTRACE_O_TRACEFORK 0x00000002
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#define PTRACE_O_TRACEVFORK 0x00000004
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#define PTRACE_O_TRACECLONE 0x00000008
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#define PTRACE_O_TRACEEXEC 0x00000010
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#define PTRACE_O_TRACEVFORKDONE 0x00000020
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#define PTRACE_O_TRACEEXIT 0x00000040
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#define PTRACE_O_MASK 0x0000007f
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/* Wait extended result codes for the above trace options. */
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#define PTRACE_EVENT_FORK 1
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#define PTRACE_EVENT_VFORK 2
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#define PTRACE_EVENT_CLONE 3
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#define PTRACE_EVENT_EXEC 4
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#define PTRACE_EVENT_VFORK_DONE 5
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#define PTRACE_EVENT_EXIT 6
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#define PTRACE_EVENT_STOP 7
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#include <asm/ptrace.h>
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#ifdef __KERNEL__
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/*
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* Ptrace flags
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*
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* The owner ship rules for task->ptrace which holds the ptrace
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* flags is simple. When a task is running it owns it's task->ptrace
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* flags. When the a task is stopped the ptracer owns task->ptrace.
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*/
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#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
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#define PT_PTRACED 0x00000001
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#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
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#define PT_TRACESYSGOOD 0x00000004
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#define PT_PTRACE_CAP 0x00000008 /* ptracer can follow suid-exec */
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/* PT_TRACE_* event enable flags */
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#define PT_EVENT_FLAG_SHIFT 4
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#define PT_EVENT_FLAG(event) (1 << (PT_EVENT_FLAG_SHIFT + (event) - 1))
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#define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK)
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#define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
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#define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
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#define PT_TRACE_EXEC PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
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#define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
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#define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
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#define PT_TRACE_MASK 0x000003f4
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/* single stepping state bits (used on ARM and PA-RISC) */
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#define PT_SINGLESTEP_BIT 31
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#define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT)
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#define PT_BLOCKSTEP_BIT 30
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#define PT_BLOCKSTEP (1<<PT_BLOCKSTEP_BIT)
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#include <linux/compiler.h> /* For unlikely. */
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#include <linux/sched.h> /* For struct task_struct. */
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extern long arch_ptrace(struct task_struct *child, long request,
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unsigned long addr, unsigned long data);
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extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
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extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
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extern void ptrace_disable(struct task_struct *);
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extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
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extern int ptrace_request(struct task_struct *child, long request,
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unsigned long addr, unsigned long data);
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extern void ptrace_notify(int exit_code);
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extern void __ptrace_link(struct task_struct *child,
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struct task_struct *new_parent);
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extern void __ptrace_unlink(struct task_struct *child);
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extern void exit_ptrace(struct task_struct *tracer);
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#define PTRACE_MODE_READ 1
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#define PTRACE_MODE_ATTACH 2
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/* Returns 0 on success, -errno on denial. */
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extern int __ptrace_may_access(struct task_struct *task, unsigned int mode);
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/* Returns true on success, false on denial. */
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extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
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static inline int ptrace_reparented(struct task_struct *child)
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{
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return !same_thread_group(child->real_parent, child->parent);
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}
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static inline void ptrace_unlink(struct task_struct *child)
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{
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if (unlikely(child->ptrace))
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__ptrace_unlink(child);
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}
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int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
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unsigned long data);
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int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
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unsigned long data);
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/**
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* ptrace_parent - return the task that is tracing the given task
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* @task: task to consider
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*
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* Returns %NULL if no one is tracing @task, or the &struct task_struct
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* pointer to its tracer.
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*
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* Must called under rcu_read_lock(). The pointer returned might be kept
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* live only by RCU. During exec, this may be called with task_lock() held
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* on @task, still held from when check_unsafe_exec() was called.
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*/
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static inline struct task_struct *ptrace_parent(struct task_struct *task)
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{
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if (unlikely(task->ptrace))
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return rcu_dereference(task->parent);
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return NULL;
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}
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/**
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* ptrace_event_enabled - test whether a ptrace event is enabled
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* @task: ptracee of interest
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* @event: %PTRACE_EVENT_* to test
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*
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* Test whether @event is enabled for ptracee @task.
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*
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* Returns %true if @event is enabled, %false otherwise.
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*/
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static inline bool ptrace_event_enabled(struct task_struct *task, int event)
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{
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return task->ptrace & PT_EVENT_FLAG(event);
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}
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/**
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* ptrace_event - possibly stop for a ptrace event notification
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* @event: %PTRACE_EVENT_* value to report
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* @message: value for %PTRACE_GETEVENTMSG to return
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*
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* Check whether @event is enabled and, if so, report @event and @message
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* to the ptrace parent.
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*
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* Called without locks.
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*/
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static inline void ptrace_event(int event, unsigned long message)
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{
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if (unlikely(ptrace_event_enabled(current, event))) {
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current->ptrace_message = message;
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ptrace_notify((event << 8) | SIGTRAP);
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} else if (event == PTRACE_EVENT_EXEC && unlikely(current->ptrace)) {
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/* legacy EXEC report via SIGTRAP */
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send_sig(SIGTRAP, current, 0);
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}
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}
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/**
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* ptrace_init_task - initialize ptrace state for a new child
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* @child: new child task
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* @ptrace: true if child should be ptrace'd by parent's tracer
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*
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* This is called immediately after adding @child to its parent's children
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* list. @ptrace is false in the normal case, and true to ptrace @child.
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*
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* Called with current's siglock and write_lock_irq(&tasklist_lock) held.
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*/
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static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
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{
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INIT_LIST_HEAD(&child->ptrace_entry);
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INIT_LIST_HEAD(&child->ptraced);
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#ifdef CONFIG_HAVE_HW_BREAKPOINT
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atomic_set(&child->ptrace_bp_refcnt, 1);
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#endif
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child->jobctl = 0;
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child->ptrace = 0;
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child->parent = child->real_parent;
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if (unlikely(ptrace) && current->ptrace) {
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child->ptrace = current->ptrace;
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__ptrace_link(child, current->parent);
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if (child->ptrace & PT_SEIZED)
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task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
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else
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sigaddset(&child->pending.signal, SIGSTOP);
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set_tsk_thread_flag(child, TIF_SIGPENDING);
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}
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}
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/**
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* ptrace_release_task - final ptrace-related cleanup of a zombie being reaped
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* @task: task in %EXIT_DEAD state
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*
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* Called with write_lock(&tasklist_lock) held.
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*/
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static inline void ptrace_release_task(struct task_struct *task)
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{
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BUG_ON(!list_empty(&task->ptraced));
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ptrace_unlink(task);
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BUG_ON(!list_empty(&task->ptrace_entry));
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}
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#ifndef force_successful_syscall_return
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/*
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* System call handlers that, upon successful completion, need to return a
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* negative value should call force_successful_syscall_return() right before
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* returning. On architectures where the syscall convention provides for a
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* separate error flag (e.g., alpha, ia64, ppc{,64}, sparc{,64}, possibly
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* others), this macro can be used to ensure that the error flag will not get
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* set. On architectures which do not support a separate error flag, the macro
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* is a no-op and the spurious error condition needs to be filtered out by some
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* other means (e.g., in user-level, by passing an extra argument to the
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* syscall handler, or something along those lines).
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*/
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#define force_successful_syscall_return() do { } while (0)
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#endif
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/*
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* <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
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*
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* These do-nothing inlines are used when the arch does not
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* implement single-step. The kerneldoc comments are here
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* to document the interface for all arch definitions.
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*/
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#ifndef arch_has_single_step
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/**
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* arch_has_single_step - does this CPU support user-mode single-step?
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*
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* If this is defined, then there must be function declarations or
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* inlines for user_enable_single_step() and user_disable_single_step().
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* arch_has_single_step() should evaluate to nonzero iff the machine
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* supports instruction single-step for user mode.
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* It can be a constant or it can test a CPU feature bit.
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*/
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#define arch_has_single_step() (0)
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/**
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* user_enable_single_step - single-step in user-mode task
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* @task: either current or a task stopped in %TASK_TRACED
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*
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* This can only be called when arch_has_single_step() has returned nonzero.
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* Set @task so that when it returns to user mode, it will trap after the
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* next single instruction executes. If arch_has_block_step() is defined,
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* this must clear the effects of user_enable_block_step() too.
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*/
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static inline void user_enable_single_step(struct task_struct *task)
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{
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BUG(); /* This can never be called. */
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}
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/**
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* user_disable_single_step - cancel user-mode single-step
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* @task: either current or a task stopped in %TASK_TRACED
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*
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* Clear @task of the effects of user_enable_single_step() and
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* user_enable_block_step(). This can be called whether or not either
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* of those was ever called on @task, and even if arch_has_single_step()
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* returned zero.
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*/
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static inline void user_disable_single_step(struct task_struct *task)
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{
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}
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#else
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extern void user_enable_single_step(struct task_struct *);
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extern void user_disable_single_step(struct task_struct *);
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#endif /* arch_has_single_step */
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#ifndef arch_has_block_step
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/**
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* arch_has_block_step - does this CPU support user-mode block-step?
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*
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* If this is defined, then there must be a function declaration or inline
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* for user_enable_block_step(), and arch_has_single_step() must be defined
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* too. arch_has_block_step() should evaluate to nonzero iff the machine
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* supports step-until-branch for user mode. It can be a constant or it
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* can test a CPU feature bit.
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*/
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#define arch_has_block_step() (0)
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/**
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* user_enable_block_step - step until branch in user-mode task
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* @task: either current or a task stopped in %TASK_TRACED
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*
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* This can only be called when arch_has_block_step() has returned nonzero,
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* and will never be called when single-instruction stepping is being used.
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* Set @task so that when it returns to user mode, it will trap after the
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* next branch or trap taken.
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*/
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static inline void user_enable_block_step(struct task_struct *task)
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{
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BUG(); /* This can never be called. */
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}
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#else
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extern void user_enable_block_step(struct task_struct *);
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#endif /* arch_has_block_step */
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#ifdef ARCH_HAS_USER_SINGLE_STEP_INFO
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extern void user_single_step_siginfo(struct task_struct *tsk,
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struct pt_regs *regs, siginfo_t *info);
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#else
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static inline void user_single_step_siginfo(struct task_struct *tsk,
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struct pt_regs *regs, siginfo_t *info)
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{
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memset(info, 0, sizeof(*info));
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info->si_signo = SIGTRAP;
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}
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#endif
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#ifndef arch_ptrace_stop_needed
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/**
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* arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
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* @code: current->exit_code value ptrace will stop with
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* @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
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*
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* This is called with the siglock held, to decide whether or not it's
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* necessary to release the siglock and call arch_ptrace_stop() with the
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* same @code and @info arguments. It can be defined to a constant if
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* arch_ptrace_stop() is never required, or always is. On machines where
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* this makes sense, it should be defined to a quick test to optimize out
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* calling arch_ptrace_stop() when it would be superfluous. For example,
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* if the thread has not been back to user mode since the last stop, the
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* thread state might indicate that nothing needs to be done.
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*/
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#define arch_ptrace_stop_needed(code, info) (0)
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#endif
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#ifndef arch_ptrace_stop
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/**
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* arch_ptrace_stop - Do machine-specific work before stopping for ptrace
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* @code: current->exit_code value ptrace will stop with
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* @info: siginfo_t pointer (or %NULL) for signal ptrace will stop with
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*
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* This is called with no locks held when arch_ptrace_stop_needed() has
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* just returned nonzero. It is allowed to block, e.g. for user memory
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* access. The arch can have machine-specific work to be done before
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* ptrace stops. On ia64, register backing store gets written back to user
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* memory here. Since this can be costly (requires dropping the siglock),
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* we only do it when the arch requires it for this particular stop, as
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* indicated by arch_ptrace_stop_needed().
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*/
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#define arch_ptrace_stop(code, info) do { } while (0)
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#endif
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extern int task_current_syscall(struct task_struct *target, long *callno,
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unsigned long args[6], unsigned int maxargs,
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unsigned long *sp, unsigned long *pc);
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#ifdef CONFIG_HAVE_HW_BREAKPOINT
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extern int ptrace_get_breakpoints(struct task_struct *tsk);
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extern void ptrace_put_breakpoints(struct task_struct *tsk);
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#else
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static inline void ptrace_put_breakpoints(struct task_struct *tsk) { }
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#endif /* CONFIG_HAVE_HW_BREAKPOINT */
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#endif /* __KERNEL */
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#endif
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