1 files changed, 377 insertions, 0 deletions

diff --git a/kernel/monitor_kernel_task.c b/kernel/monitor_kernel_task.c
new file mode 100644
index 0000000..3b57152
--- /dev/null
+++ b/kernel/monitor_kernel_task.c
@@ -0,0 +1,377 @@
+#include "monitor_kernel_task.h"
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/syscall.h> // for syscall_get_nr
+#include <linux/irq.h>
+#include <linux/sched/mm.h> // for get_task_mm
+#include <linux/syscalls.h>
+#include <linux/tracehook.h>
+
+struct stack_trace {
+  unsigned int nr_entries, max_entries;
+  unsigned long *entries;
+  int skip; /* input argument: How many entries to skip */
+};
+
+struct stack_frame_user {
+  const void __user *next_fp;
+  unsigned long ret_addr;
+};
+
+static inline int diag_get_task_type(struct task_struct *tsk) {
+  if (orig_get_task_type)
+    return orig_get_task_type(&tsk->se);
+  return 0;
+}
+
+static inline int orig_diag_cgroup_name(struct cgroup *cgrp, char *buf,
+                                        size_t buflen) {
+  if (orig_kernfs_name && cgrp && cgrp->kn) {
+    return orig_kernfs_name(cgrp->kn, buf, buflen);
+  } else {
+    return 0;
+  }
+}
+
+static inline mm_info *find_mm_info(mm_tree *mm_tree, struct mm_struct *mm) {
+  mm_info *info;
+  if (mm == NULL)
+    return NULL;
+  info = radix_tree_lookup(&mm_tree->mm_tree, (unsigned long)mm);
+  return info;
+}
+
+static void __diag_cgroup_name(struct task_struct *tsk, char *buf,
+                               unsigned int count, int cgroup) {
+  int cgroup_id = cpuacct_cgrp_id;
+
+  memset(buf, 0, count);
+
+  if (cgroup == 1) {
+    cgroup_id = cpuset_cgrp_id;
+  }
+
+  if (tsk && tsk->cgroups && tsk->cgroups->subsys &&
+      tsk->cgroups->subsys[cgroup_id] &&
+      tsk->cgroups->subsys[cgroup_id]->cgroup) {
+    orig_diag_cgroup_name(tsk->cgroups->subsys[cgroup_id]->cgroup, buf, count);
+  }
+}
+
+static void diag_cgroup_name(struct task_struct *tsk, char *buf,
+                             unsigned int count, int cgroup) {
+  __diag_cgroup_name(tsk, buf, count, cgroup);
+}
+
+static int copy_stack_frame(const void __user *fp,
+                            struct stack_frame_user *frame) {
+  int ret;
+
+  ret = 1;
+  pagefault_disable();
+  if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
+    ret = 0;
+  pagefault_enable();
+
+  return ret;
+}
+
+static int copy_stack_frame_remote(struct task_struct *tsk,
+                                   const void __user *fp,
+                                   struct stack_frame_user *frame) {
+  int ret;
+  struct mm_struct *mm;
+
+  mm = get_task_mm(tsk);
+  if (!mm)
+    return 0;
+
+  ret = orig_access_remote_vm(mm, (unsigned long)fp, frame, sizeof(*frame), 0);
+  mmput(mm);
+
+  return ret;
+}
+
+static inline void save_stack_trace_user_remote(struct task_struct *tsk,
+                                                struct stack_trace *trace) {
+  const struct pt_regs *regs = task_pt_regs(tsk);
+  const void __user *fp = (const void __user *)regs->bp;
+  int count = 0;
+
+  if (in_atomic() || irqs_disabled()) {
+    return;
+  }
+
+  if (trace->nr_entries < trace->max_entries)
+    trace->entries[trace->nr_entries++] = regs->ip;
+
+  while (trace->nr_entries < trace->max_entries) {
+    struct stack_frame_user frame;
+
+    frame.next_fp = NULL;
+    frame.ret_addr = 0;
+
+    if (!copy_stack_frame_remote(tsk, fp, &frame)) {
+      break;
+    }
+
+    if ((unsigned long)fp < regs->sp)
+      break;
+
+    if (frame.ret_addr) {
+      trace->entries[trace->nr_entries++] = frame.ret_addr;
+    } else
+      break;
+
+    if (fp == frame.next_fp)
+      break;
+    fp = frame.next_fp;
+
+    count++;
+    /**
+     * 线上环境发现这里有hardlockup，这里强制退出
+     */
+    if (count >= trace->max_entries || count >= 100)
+      break;
+  }
+}
+
+static inline void __save_stack_trace_user(struct stack_trace *trace) {
+  const struct pt_regs *regs = task_pt_regs(current);
+  const void __user *fp = (const void __user *)regs->bp;
+  int count = 0;
+
+  if (trace->nr_entries < trace->max_entries)
+    trace->entries[trace->nr_entries++] = regs->ip;
+
+  while (trace->nr_entries < trace->max_entries) {
+    struct stack_frame_user frame;
+
+    frame.next_fp = NULL;
+    frame.ret_addr = 0;
+    if (!copy_stack_frame(fp, &frame))
+      break;
+    if ((unsigned long)fp < regs->sp)
+      break;
+    if (frame.ret_addr) {
+      trace->entries[trace->nr_entries++] = frame.ret_addr;
+    }
+    if (fp == frame.next_fp)
+      break;
+    fp = frame.next_fp;
+    count++;
+    /**
+     * 线上环境发现这里有hardlockup，这里强制退出
+     */
+    if (count >= trace->max_entries || count >= 100)
+      break;
+  }
+}
+
+void perfect_save_stack_trace_user(struct stack_trace *trace) {
+  /*
+   * Trace user stack if we are not a kernel thread
+   */
+  if (current->mm) {
+    __save_stack_trace_user(trace);
+  }
+  if (trace->nr_entries < trace->max_entries)
+    trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
+void diagnose_save_stack_trace_user(unsigned long *backtrace) {
+  struct stack_trace trace;
+
+  memset(&trace, 0, sizeof(trace));
+  memset(backtrace, 0, BACKTRACE_DEPTH2 * sizeof(unsigned long));
+  trace.max_entries = BACKTRACE_DEPTH2;
+  trace.entries = backtrace;
+  perfect_save_stack_trace_user(&trace);
+}
+
+void diagnose_save_stack_trace_user_remote(struct task_struct *tsk,
+                                           unsigned long *backtrace) {
+  struct stack_trace trace;
+
+  memset(&trace, 0, sizeof(trace));
+  memset(backtrace, 0, BACKTRACE_DEPTH2 * sizeof(unsigned long));
+  trace.max_entries = BACKTRACE_DEPTH2;
+  trace.entries = backtrace;
+
+  /*
+   * Trace user stack if we are not a kernel thread
+   */
+  if (tsk->mm) {
+    save_stack_trace_user_remote(tsk, &trace);
+  }
+  if (trace.nr_entries < trace.max_entries)
+    trace.entries[trace.nr_entries++] = ULONG_MAX;
+}
+
+void diag_task_brief(struct task_struct *tsk, task_detail *detail) {
+  struct pid_namespace *ns;
+  struct pt_regs *task_regs;
+  struct task_struct *leader;
+  struct pt_regs *irq_regs;
+
+  if (!detail)
+    return;
+
+  memset(detail, 0, sizeof(task_detail));
+
+  if (!tsk || tsk->exit_state == EXIT_ZOMBIE) // zombie
+    return;
+  leader = tsk->group_leader;
+  if (!leader || leader->exit_state == EXIT_ZOMBIE) {
+    return;
+  }
+
+  if (tsk != current) { // not current task
+    detail->user_mode = -1;
+    detail->syscallno = -1;
+  } else if (!tsk->mm) { // current task but kernel thread
+    detail->user_mode = 0;
+    detail->syscallno = -1;
+  } else {                     // current task and user thread
+    irq_regs = get_irq_regs(); // get current irq regs
+    task_regs = task_pt_regs(tsk);
+
+    if ((irq_regs && user_mode(irq_regs)) ||
+        (task_regs && user_mode(task_regs))) {
+      detail->user_mode = 1; // user mode
+    } else {
+      detail->user_mode = 0; // kernel mode
+    }
+
+    if (task_regs) {
+      detail->syscallno = syscall_get_nr(tsk, task_regs); // get syscall no
+    }
+  }
+
+  if (tsk->sched_class == orig_idle_sched_class) // idle task
+    detail->sys_task = 2;
+  else if (!tsk->mm) // kernel thread
+    detail->sys_task = 1;
+  else
+    detail->sys_task = 0;
+
+  detail->pid = tsk->pid;                      // pid
+  detail->tgid = tsk->tgid;                    // tgid
+  detail->state = tsk->__state;                // state
+  detail->task_type = diag_get_task_type(tsk); // task type
+  ns = task_active_pid_ns(tsk);                // container pid
+  if (ns && ns != &init_pid_ns) {
+    detail->container_pid = task_pid_nr_ns(tsk, ns);
+    detail->container_tgid = task_tgid_nr_ns(tsk, ns);
+  } else {
+    detail->container_pid = tsk->pid;
+    detail->container_tgid = tsk->tgid;
+  }
+  strncpy(detail->comm, tsk->comm, TASK_COMM_LEN);
+  detail->comm[TASK_COMM_LEN - 1] = 0; // comm name
+  diag_cgroup_name(tsk, detail->cgroup_buf, CGROUP_NAME_LEN, 0);
+  diag_cgroup_name(tsk, detail->cgroup_cpuset, CGROUP_NAME_LEN, 1);
+
+  detail->cgroup_buf[CGROUP_NAME_LEN - 1] = 0;    // cgroup name
+  detail->cgroup_cpuset[CGROUP_NAME_LEN - 1] = 0; // cgroup cpuset name
+}
+
+void diag_task_user_stack(struct task_struct *tsk, user_stack_detail *detail) {
+  struct pt_regs *regs;
+  unsigned long sp, ip, bp;
+  struct task_struct *leader;
+
+  if (!detail)
+    return;
+
+  detail->stack[0] = 0;
+  if (!tsk || !tsk->mm)
+    return;
+
+  leader = tsk->group_leader;
+  if (!leader || !leader->mm || leader->exit_state == EXIT_ZOMBIE) {
+    return;
+  }
+
+  sp = 0;
+  ip = 0;
+  bp = 0;
+  regs = task_pt_regs(tsk);
+  if (regs) {
+    sp = regs->sp;
+#if defined(DIAG_ARM64)
+    ip = regs->pc;
+    bp = regs->sp;
+#else
+    ip = regs->ip;
+    bp = regs->bp;
+#endif
+  }
+#if defined(DIAG_ARM64)
+  detail->regs = regs->user_regs;
+#else
+  detail->regs = *regs;
+#endif
+  detail->sp = sp;
+  detail->ip = ip;
+  detail->bp = bp;
+
+  if (tsk == current) {
+    diagnose_save_stack_trace_user(detail->stack);
+  } else {
+    diagnose_save_stack_trace_user_remote(tsk, detail->stack);
+  }
+}
+
+void diag_task_kern_stack(struct task_struct *tsk, kern_stack_detail *detail) {
+  orig_stack_trace_save_tsk(tsk, detail->stack, BACKTRACE_DEPTH2, 0);
+}
+
+void dump_proc_chains_argv(int style, struct task_struct *tsk, mm_tree *mm_tree,
+                           proc_chains_detail *detail) {
+  struct task_struct *walker;
+  mm_info *mm_info;
+  int cnt = 0;
+  int i = 0;
+  struct task_struct *leader;
+
+  for (i = 0; i < PROCESS_CHAINS_COUNT; i++) {
+    detail->chains[i][0] = 0;
+    detail->tgid[i] = 0;
+  }
+  if (style == 0)
+    return;
+
+  if (!tsk || !tsk->mm)
+    return;
+
+  leader = tsk->group_leader;
+  if (!leader || !leader->mm ||
+      leader->exit_state == EXIT_ZOMBIE) { // leader is zombie or no mm
+    return;
+  }
+
+  rcu_read_lock();
+  walker = tsk;
+
+  while (walker->pid > 0) {
+    if (!thread_group_leader(walker))
+      walker = rcu_dereference(walker->group_leader);
+    mm_info = find_mm_info(mm_tree, walker->mm);
+    if (mm_info) {
+      if (mm_info->cgroup_buf[0] == 0)
+        diag_cgroup_name(walker, mm_info->cgroup_buf, 255, 0);
+      strncpy(detail->chains[cnt], mm_info->argv, PROCESS_ARGV_LEN);
+      detail->full_argv[cnt] = 1;
+    } else {
+      strncpy(detail->chains[cnt], walker->comm, TASK_COMM_LEN);
+      detail->full_argv[cnt] = 0;
+    }
+    detail->tgid[cnt] = walker->pid;
+    walker = rcu_dereference(walker->real_parent);
+    cnt++;
+    if (cnt >= PROCESS_CHAINS_COUNT)
+      break;
+  }
+  rcu_read_unlock();
+}
\ No newline at end of file