lkml.org 
[lkml]   [2003]   [Jan]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
SubjectRe: [PATCH] fix CONFIG_DEVFS=y root=<number>
From
init/do_mounts.c: In function `do_read_dir':
init/do_mounts.c:335: warning: `n' might be used uninitialized in this function

and it loops trying to intrepret the directory listing :(

After some searching, I realized the directory contents read in were garbage,
looked at that code closer, and found the cause of the problem:

for (bytes = 0; bytes < len; bytes += n) {
- n = sys_getdents64(fd, p + n, len - bytes);
+ n = sys_getdents64(fd, p + bytes, len - bytes);


updated patch below:

# Patch from Milton Miller <miltonm@bga.com>
# Based on discovery work by Adam J. Richter <adam@yggdrasil.com>
# Cleanups by Andrew Morton (akpm@digeo.com)
#
# There's some init-time code which is supposed to read a devfs directory by
# expanding the bufer until the whole directory fits. But the logic is wrong
# and it only works if the whole directory fits into 512 bytes.
#
# So fix that up, and also clean up some coding in there, and rationalise the
# duplicated definition of linux_dirent64.
# --------------------------------------------
#
diff -Nru a/fs/readdir.c b/fs/readdir.c
--- a/fs/readdir.c Sun Jan 5 01:35:40 2003
+++ b/fs/readdir.c Sun Jan 5 01:35:40 2003
@@ -11,6 +11,7 @@
#include <linux/file.h>
#include <linux/smp_lock.h>
#include <linux/fs.h>
+#include <linux/dirent.h>
#include <linux/security.h>

#include <asm/uaccess.h>
@@ -193,17 +194,6 @@
out:
return error;
}
-
-/*
- * And even better one including d_type field and 64bit d_ino and d_off.
- */
-struct linux_dirent64 {
- u64 d_ino;
- s64 d_off;
- unsigned short d_reclen;
- unsigned char d_type;
- char d_name[0];
-};

#define ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1))

diff -Nru a/include/linux/dirent.h b/include/linux/dirent.h
--- a/include/linux/dirent.h Sun Jan 5 01:35:40 2003
+++ b/include/linux/dirent.h Sun Jan 5 01:35:40 2003
@@ -16,4 +16,17 @@
char d_name[256];
};

+#ifdef __KERNEL__
+
+struct linux_dirent64 {
+ u64 d_ino;
+ s64 d_off;
+ unsigned short d_reclen;
+ unsigned char d_type;
+ char d_name[0];
+};
+
+#endif /* __KERNEL__ */
+
+
#endif
diff -Nru a/init/do_mounts.c b/init/do_mounts.c
--- a/init/do_mounts.c Sun Jan 5 01:35:40 2003
+++ b/init/do_mounts.c Sun Jan 5 01:35:40 2003
@@ -13,6 +13,7 @@
#include <linux/suspend.h>
#include <linux/root_dev.h>
#include <linux/mount.h>
+#include <linux/dirent.h>
#include <linux/security.h>

#include <linux/nfs_fs.h>
@@ -324,22 +325,32 @@
#endif

#ifdef CONFIG_DEVFS_FS
+
+/*
+ * If the dir will fit in *buf, return its length. If it won't fit, return
+ * zero. Return -ve on error.
+ */
static int __init do_read_dir(int fd, void *buf, int len)
{
long bytes, n;
char *p = buf;
lseek(fd, 0, 0);

- for (bytes = 0, p = buf; bytes < len; bytes += n, p+=n) {
- n = sys_getdents64(fd, p, len - bytes);
+ for (bytes = 0; bytes < len; bytes += n) {
+ n = sys_getdents64(fd, p + bytes, len - bytes);
if (n < 0)
- return -1;
+ return n;
if (n == 0)
return bytes;
}
return 0;
}

+/*
+ * Try to read all of a directory. Returns the contents at *p, which
+ * is kmalloced memory. Returns the number of bytes read at *len. Returns
+ * NULL on error.
+ */
static void * __init read_dir(char *path, int *len)
{
int size;
@@ -349,7 +360,7 @@
if (fd < 0)
return NULL;

- for (size = 1<<9; size < (1<<18); size <<= 1) {
+ for (size = 1 << 9; size <= (1 << MAX_ORDER); size <<= 1) {
void *p = kmalloc(size, GFP_KERNEL);
int n;
if (!p)
@@ -361,6 +372,8 @@
return p;
}
kfree(p);
+ if (n == -EINVAL)
+ continue; /* Try a larger buffer */
if (n < 0)
break;
}
@@ -368,14 +381,6 @@
return NULL;
}
#endif
-
-struct linux_dirent64 {
- u64 d_ino;
- s64 d_off;
- unsigned short d_reclen;
- unsigned char d_type;
- char d_name[0];
-};

static int __init find_in_devfs(char *path, dev_t dev)
{
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2005-03-22 13:32    [W:0.047 / U:7.172 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site