tracing: Map all PIDs to command lines

[android-x86/kernel.git] / kernel / trace / trace.c

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index bca0b6d..4eea58a 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1935,14 +1935,13 @@ static void tracing_stop_tr(struct trace_array *tr)
 
 static int trace_save_cmdline(struct task_struct *tsk)
 {
-       unsigned pid, idx;
+       unsigned tpid, idx;
 
        /* treat recording of idle task as a success */
        if (!tsk->pid)
                return 1;
 
-       if (unlikely(tsk->pid > PID_MAX_DEFAULT))
-               return 0;
+       tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
 
        /*
         * It's not the end of the world if we don't get
@@ -1953,26 +1952,15 @@ static int trace_save_cmdline(struct task_struct *tsk)
        if (!arch_spin_trylock(&trace_cmdline_lock))
                return 0;
 
-       idx = savedcmd->map_pid_to_cmdline[tsk->pid];
+       idx = savedcmd->map_pid_to_cmdline[tpid];
        if (idx == NO_CMDLINE_MAP) {
                idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
 
-               /*
-                * Check whether the cmdline buffer at idx has a pid
-                * mapped. We are going to overwrite that entry so we
-                * need to clear the map_pid_to_cmdline. Otherwise we
-                * would read the new comm for the old pid.
-                */
-               pid = savedcmd->map_cmdline_to_pid[idx];
-               if (pid != NO_CMDLINE_MAP)
-                       savedcmd->map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
-
-               savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
-               savedcmd->map_pid_to_cmdline[tsk->pid] = idx;
-
+               savedcmd->map_pid_to_cmdline[tpid] = idx;
                savedcmd->cmdline_idx = idx;
        }
 
+       savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
        set_cmdline(idx, tsk->comm);
 
        arch_spin_unlock(&trace_cmdline_lock);
@@ -1983,6 +1971,7 @@ static int trace_save_cmdline(struct task_struct *tsk)
 static void __trace_find_cmdline(int pid, char comm[])
 {
        unsigned map;
+       int tpid;
 
        if (!pid) {
                strcpy(comm, "<idle>");
@@ -1994,16 +1983,16 @@ static void __trace_find_cmdline(int pid, char comm[])
                return;
        }
 
-       if (pid > PID_MAX_DEFAULT) {
-               strcpy(comm, "<...>");
-               return;
+       tpid = pid & (PID_MAX_DEFAULT - 1);
+       map = savedcmd->map_pid_to_cmdline[tpid];
+       if (map != NO_CMDLINE_MAP) {
+               tpid = savedcmd->map_cmdline_to_pid[map];
+               if (tpid == pid) {
+                       strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
+                       return;
+               }
        }
-
-       map = savedcmd->map_pid_to_cmdline[pid];
-       if (map != NO_CMDLINE_MAP)
-               strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
-       else
-               strcpy(comm, "<...>");
+       strcpy(comm, "<...>");
 }
 
 void trace_find_cmdline(int pid, char comm[])