fs: add backtrace to where file opens

Signed-off-by: Xu Xingliang <xuxingliang@xiaomi.com>

boards/sim/sim/sim/configs/citest/defconfig

@@ -49,6 +49,7 @@ CONFIG_FRAME_POINTER=y
 CONFIG_FSUTILS_PASSWD=y
 CONFIG_FSUTILS_PASSWD_READONLY=y
 CONFIG_FS_AIO=y
+CONFIG_FS_BACKTRACE=8
 CONFIG_FS_BINFS=y
 CONFIG_FS_FAT=y
 CONFIG_FS_HOSTFS=y

fs/inode/fs_files.c

@@ -30,6 +30,7 @@
 #include <sched.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <stdio.h>
 
 #include <nuttx/fs/fs.h>
 #include <nuttx/kmalloc.h>
@@ -460,6 +461,8 @@ found:
       inode_addref(inode);
     }
 
+  FS_ADD_BACKTRACE(filep);
+
 #ifdef CONFIG_FDCHECK
   return fdcheck_protect(i * CONFIG_NFILE_DESCRIPTORS_PER_BLOCK + j);
 #else
@@ -487,6 +490,27 @@ int file_allocate(FAR struct inode *inode, int oflags, off_t pos,
                                 pos, priv, minfd, addref);
 }
 
+FAR char *file_dump_backtrace(FAR struct file *filep, FAR char *buffer,
+                              size_t len)
+{
+#if CONFIG_FS_BACKTRACE > 0
+  FAR const char *format = "%0*p ";
+  int k;
+
+  buffer[0] = '\0';
+  for (k = 0; k < CONFIG_FS_BACKTRACE && filep->f_backtrace[k]; k++)
+    {
+      snprintf(buffer + k * FS_BACKTRACE_WIDTH,
+               len - k * FS_BACKTRACE_WIDTH,
+               format, FS_BACKTRACE_WIDTH - 1,
+               filep->f_backtrace[k]);
+    }
+#else
+  buffer[0] = '\0';
+#endif
+  return buffer;
+}
+
 /****************************************************************************
  * Name: files_duplist
  *

fs/inode/inode.h

@@ -32,6 +32,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <dirent.h>
+#include <sched.h>
 
 #include <nuttx/kmalloc.h>
 #include <nuttx/fs/fs.h>
@@ -65,6 +66,23 @@
     } \
   while (0)
 
+#if CONFIG_FS_BACKTRACE > 0
+#  define FS_ADD_BACKTRACE(filep) \
+     do \
+       { \
+          int n = sched_backtrace(_SCHED_GETTID(), filep->f_backtrace, \
+                                  CONFIG_FS_BACKTRACE, \
+                                  CONFIG_FS_BACKTRACE_SKIP); \
+          if (n < CONFIG_FS_BACKTRACE) \
+            { \
+              (filep->f_backtrace)[n] = NULL; \
+            } \
+       } \
+     while (0)
+#else
+#  define FS_ADD_BACKTRACE(filep)
+#endif
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/

fs/procfs/fs_procfsproc.c

@@ -1244,8 +1244,6 @@ static ssize_t proc_groupfd(FAR struct proc_file_s *procfile,
                             size_t buflen, off_t offset)
 {
   FAR struct task_group_s *group = tcb->group;
-  FAR struct file *filep;
-  char path[PATH_MAX];
   size_t remaining;
   size_t linesize;
   size_t copysize;
@@ -1253,6 +1251,10 @@ static ssize_t proc_groupfd(FAR struct proc_file_s *procfile,
   int count;
   int i;
 
+  FAR struct file *filep;
+  char path[PATH_MAX];
+  char backtrace[FS_BACKTRACE_BUFFER_LEN];
+
   DEBUGASSERT(group != NULL);
 
   count = files_countlist(&group->tg_filelist);
@@ -1265,8 +1267,14 @@ static ssize_t proc_groupfd(FAR struct proc_file_s *procfile,
   totalsize = 0;
 
   linesize   = procfs_snprintf(procfile->line, STATUS_LINELEN,
-                               "\n%-3s %-7s %-4s %-9s %s\n",
+                               "\n%-3s %-7s %-4s %-9s %-14s %s\n",
-                               "FD", "OFLAGS", "TYPE", "POS", "PATH");
+                               "FD", "OFLAGS", "TYPE", "POS", "PATH",
+#if CONFIG_FS_BACKTRACE > 0
+                               "BACKTRACE"
+#else
+                               ""
+#endif
+                               );
   copysize   = procfs_memcpy(procfile->line, linesize, buffer, remaining,
                              &offset);
 
@@ -1298,12 +1306,22 @@ static ssize_t proc_groupfd(FAR struct proc_file_s *procfile,
         }
 
       linesize   = procfs_snprintf(procfile->line, STATUS_LINELEN,
-                                   "%-3d %-7d %-4x %-9ld %s\n",
+                                   "%-3d %-7d %-4x %-9ld %-14s %s\n",
                                    i, filep->f_oflags,
                                    INODE_GET_TYPE(filep->f_inode),
-                                   (long)filep->f_pos, path);
+                                   (long)filep->f_pos, path,
+                                   file_dump_backtrace(filep,
+                                                       backtrace,
+                                                       sizeof(backtrace)
+                                                      )
+                                  );
       copysize   = procfs_memcpy(procfile->line, linesize,
                                  buffer, remaining, &offset);
+      if (linesize + 1 == STATUS_LINELEN)
+        {
+          procfile->line[STATUS_LINELEN - 2] = '\n';
+          linesize = STATUS_LINELEN;
+        }
 
       totalsize += copysize;
       buffer    += copysize;

fs/vfs/Kconfig

@@ -64,3 +64,16 @@ config SIGNAL_FD_NPOLLWAITERS
 		Maximum number of threads that can be waiting on poll()
 
 endif # SIGNAL_FD
+
+config FS_BACKTRACE
+	int "VFS backtrace"
+	default 0
+	---help---
+		Add backtrace to vfs file open.
+
+config FS_BACKTRACE_SKIP
+	int "Backtrace to skip"
+	default 2
+	depends on FS_BACKTRACE > 0
+	---help---
+		Skip depth of backtrace.

fs/vfs/fs_dup2.c

@@ -174,6 +174,7 @@ int file_dup3(FAR struct file *filep1, FAR struct file *filep2, int flags)
   filep2->f_tag_fdcheck = filep1->f_tag_fdcheck;
 #endif
 
+  FS_ADD_BACKTRACE(filep2);
   return OK;
 }
 

include/nuttx/fs/fs.h

@@ -164,6 +164,9 @@
 #define CH_STAT_ATIME      (1 << 3)
 #define CH_STAT_MTIME      (1 << 4)
 
+#define FS_BACKTRACE_WIDTH      (sizeof(uintptr_t) * 2 + 3) /* 3: ' 0x' prefix */
+#define FS_BACKTRACE_BUFFER_LEN (CONFIG_FS_BACKTRACE * FS_BACKTRACE_WIDTH + 1)
+
 /****************************************************************************
  * Public Type Definitions
  ****************************************************************************/
@@ -475,6 +478,10 @@ struct file
 #ifdef CONFIG_FDCHECK
   uint8_t           f_tag_fdcheck; /* File owner fdcheck tag, init to 0 */
 #endif
+
+#if CONFIG_FS_BACKTRACE > 0
+  FAR void         *f_backtrace[CONFIG_FS_BACKTRACE]; /* Backtrace to while file opens */
+#endif
 };
 
 /* This defines a two layer array of files indexed by the file descriptor.
@@ -946,6 +953,20 @@ int file_allocate_from_tcb(FAR struct tcb_s *tcb, FAR struct inode *inode,
 int file_allocate(FAR struct inode *inode, int oflags, off_t pos,
                   FAR void *priv, int minfd, bool addref);
 
+/****************************************************************************
+ * Name: file_dump_backtrace
+ *
+ * Description:
+ *   Dump the backtrace of the file open to given buffer.
+ *
+ * Returned Value:
+ *     Returns the backtrace string, it could be empty.
+ *
+ ****************************************************************************/
+
+FAR char *file_dump_backtrace(FAR struct file *filep, FAR char *buffer,
+                              size_t len);
+
 /****************************************************************************
  * Name: file_dup
  *