sched/tcb: add a reference count to the TCB to prevent it from being deleted.

To replace the large lock with smaller ones and reduce the large locks related to the TCB,
in many scenarios, we only need to ensure that the TCB won't be released
instead of locking, thus reducing the possibility of lock recursion.

Signed-off-by: hujun5 <hujun5@xiaomi.com>

Author: hujun260

arch/risc-v/src/common/riscv_exception.c

@@ -111,6 +111,7 @@ int riscv_exception(int mcause, void *regs, void *args)
       _alert("Segmentation fault in %s (PID %d: %s)\n", get_task_name(ptcb),
              tcb->pid, get_task_name(tcb));
 
+      nxsched_put_tcb(ptcb);
       tcb->flags |= TCB_FLAG_FORCED_CANCEL;
 
       /* Return to _exit function in privileged mode with argument SIGSEGV */

boards/arm/stm32/nucleo-f302r8/scripts/ld.script

@@ -30,7 +30,7 @@
 
 MEMORY
 {
-  flash (rx) : ORIGIN = 0x08000000, LENGTH = 64K
+  flash (rx) : ORIGIN = 0x08000000, LENGTH = 96K
   sram (rwx) : ORIGIN = 0x20000000, LENGTH = 16K
 }
 

boards/arm/stm32/nucleo-g431rb/scripts/ld.script

@@ -47,7 +47,7 @@
 
 MEMORY
 {
-    flash (rx) : ORIGIN = 0x08000000, LENGTH = 128K
+    flash (rx) : ORIGIN = 0x08000000, LENGTH = 256K
     sram (rwx) : ORIGIN = 0x20000000, LENGTH = 22K
 }
 

drivers/note/note_driver.c

@@ -2109,6 +2109,7 @@ FAR char *note_get_taskname(pid_t pid, FAR char *buf, size_t len)
   if (tcb != NULL)
     {
       strlcpy(buf, tcb->name, len);
+      nxsched_put_tcb(tcb);
       return buf;
     }
 

drivers/syslog/vsyslog.c

@@ -36,6 +36,7 @@
 #include <nuttx/streams.h>
 #include <nuttx/syslog/syslog.h>
 
+#include "sched/sched.h"
 #include "syslog.h"
 
 /****************************************************************************

fs/inode/fs_files.c

@@ -255,6 +255,7 @@ static void task_fssync(FAR struct tcb_s *tcb, FAR void *arg)
           ctcb = nxsched_get_tcb(pid);
           if (ctcb == NULL || ctcb->group == NULL || ctcb != tcb)
             {
+              nxsched_put_tcb(ctcb);
               return;
             }
 
@@ -264,6 +265,8 @@ static void task_fssync(FAR struct tcb_s *tcb, FAR void *arg)
               file_fsync(filep);
               file_put(filep);
             }
+
+          nxsched_put_tcb(ctcb);
         }
     }
 }

fs/procfs/fs_procfs.c

@@ -942,8 +942,7 @@ static int procfs_readdir(FAR struct inode *mountpt,
           /* Verify that the pid still refers to an active task/thread */
 
           pid_t pid = level0->pid[index];
-          FAR struct tcb_s *tcb = nxsched_get_tcb(pid);
-          if (!tcb)
+          if (!nxsched_verify_pid(pid))
             {
               ferr("ERROR: PID %d is no longer valid\n", pid);
               return -ENOENT;

fs/procfs/fs_procfsmeminfo.c

@@ -539,6 +539,7 @@ static ssize_t memdump_write(FAR struct file *filep, FAR const char *buffer,
         }
 
       tcb->flags |= TCB_FLAG_HEAP_DUMP;
+      nxsched_put_tcb(tcb);
       return buflen;
     }
   else if ((p = strstr(buffer, "off")) != NULL)
@@ -552,6 +553,7 @@ static ssize_t memdump_write(FAR struct file *filep, FAR const char *buffer,
         }
 
       tcb->flags &= ~TCB_FLAG_HEAP_DUMP;
+      nxsched_put_tcb(tcb);
       return buflen;
     }
 #endif

fs/procfs/fs_procfsproc.c

@@ -62,6 +62,7 @@
 #include <nuttx/lib/lib.h>
 
 #include "fs_heap.h"
+#include "sched/sched.h"
 
 #if !defined(CONFIG_SCHED_CPULOAD_NONE) || defined(CONFIG_SCHED_CRITMONITOR)
 #  include <nuttx/clock.h>
@@ -1462,7 +1463,6 @@ static int proc_open(FAR struct file *filep, FAR const char *relpath,
 {
   FAR struct proc_file_s *procfile;
   FAR const struct proc_node_s *node;
-  FAR struct tcb_s *tcb;
   FAR char *ptr;
   unsigned long tmp;
   pid_t pid;
@@ -1508,9 +1508,7 @@ static int proc_open(FAR struct file *filep, FAR const char *relpath,
   /* Now verify that a task with this task/thread ID exists */
 
   pid = (pid_t)tmp;
-
-  tcb = nxsched_get_tcb(pid);
-  if (tcb == NULL)
+  if (!nxsched_verify_pid(pid))
     {
       ferr("ERROR: PID %d is no longer valid\n", pid);
       return -ENOENT;
@@ -1663,6 +1661,8 @@ static ssize_t proc_read(FAR struct file *filep, FAR char *buffer,
 
   leave_critical_section(flags);
 
+  nxsched_put_tcb(tcb);
+
   /* Update the file offset */
 
   if (ret > 0)
@@ -1714,6 +1714,7 @@ static ssize_t proc_write(FAR struct file *filep, FAR const char *buffer,
         break;
     }
 
+  nxsched_put_tcb(tcb);
   return ret;
 }
 
@@ -1769,7 +1770,6 @@ static int proc_opendir(FAR const char *relpath,
 {
   FAR struct proc_dir_s *procdir;
   FAR const struct proc_node_s *node;
-  FAR struct tcb_s *tcb;
   unsigned long tmp;
   FAR char *ptr;
   pid_t pid;
@@ -1819,9 +1819,7 @@ static int proc_opendir(FAR const char *relpath,
   /* Now verify that a task with this task/thread ID exists */
 
   pid = (pid_t)tmp;
-
-  tcb = nxsched_get_tcb(pid);
-  if (tcb == NULL)
+  if (!nxsched_verify_pid(pid))
     {
       ferr("ERROR: PID %d is not valid\n", pid);
       return -ENOENT;
@@ -1911,7 +1909,6 @@ static int proc_readdir(FAR struct fs_dirent_s *dir,
 {
   FAR struct proc_dir_s *procdir;
   FAR const struct proc_node_s *node = NULL;
-  FAR struct tcb_s *tcb;
   unsigned int index;
   pid_t pid;
   int ret;
@@ -1939,9 +1936,7 @@ static int proc_readdir(FAR struct fs_dirent_s *dir,
       /* Verify that the pid still refers to an active task/thread */
 
       pid = procdir->pid;
-
-      tcb = nxsched_get_tcb(pid);
-      if (tcb == NULL)
+      if (!nxsched_verify_pid(pid))
         {
           ferr("ERROR: PID %d is no longer valid\n", pid);
           return -ENOENT;
@@ -2013,7 +2008,6 @@ static int proc_rewinddir(struct fs_dirent_s *dir)
 static int proc_stat(const char *relpath, struct stat *buf)
 {
   FAR const struct proc_node_s *node;
-  FAR struct tcb_s *tcb;
   unsigned long tmp;
   FAR char *ptr;
   pid_t pid;
@@ -2057,9 +2051,7 @@ static int proc_stat(const char *relpath, struct stat *buf)
   /* Now verify that a task with this task/thread ID exists */
 
   pid = (pid_t)tmp;
-
-  tcb = nxsched_get_tcb(pid);
-  if (tcb == NULL)
+  if (!nxsched_verify_pid(pid))
     {
       ferr("ERROR: PID %d is no longer valid\n", pid);
       return -ENOENT;

include/nuttx/mm/mm.h

@@ -152,7 +152,7 @@
     ((node) != NULL && (dump)->pid == (node)->pid)
 #  define MM_DUMP_LEAK(dump, node) \
     ((node) != NULL && (dump)->pid == PID_MM_LEAK && (node)->pid >= 0 && \
-     nxsched_get_tcb((node)->pid) == NULL)
+    !nxsched_verify_pid((node)->pid))
 #else
 #  define MM_DUMP_ALLOC(dump,node)  ((dump)->pid == PID_MM_ALLOC)
 #  define MM_DUMP_SEQNO(dump,node)  (true)