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SubjectRe: [PATCH] fix stack usage in fs/intermezzo/journal.c
On Fri, 14 March 2003 08:09:30 -0800, Randy.Dunlap wrote:
>
> I guess one of us needs some guidance here.
> I thought that sizeof(*buf) == 1 here, not 4096. Anybody?
> I don't see how sizeof() can determine the kmalloc-ed size,
> so I would use BUF_SIZE instead, with
> #define BUF_SIZE 4096

I'd love to say you're wrong, but you're not. New patch is below.
FUNCTION_NAME_BUFSIZE should have less name collision than BUF_SIZE,
but someone who knows intermezzo better than me might find a much
nicer name.

Jörn

--
Jörn Engel
mailto: joern@wohnheim.fh-wedel.de
http://wohnheim.fh-wedel.de/~joern
Phone: +49 179 6704074

--- linux-2.5.64/fs/intermezzo/journal.c Mon Feb 24 20:05:05 2003
+++ linux-2.5.64-i2o/fs/intermezzo/journal.c Fri Mar 14 17:37:18 2003
@@ -1239,12 +1239,15 @@
return izo_rcvd_write(fset, &rec);
}

+/* FIXME: should the below go into some header file? */
+#define PRESTO_COPY_KML_TAIL_BUFSIZE 4096
struct file * presto_copy_kml_tail(struct presto_file_set *fset,
unsigned long int start)
{
struct file *f;
int len;
loff_t read_off, write_off, bytes;
+ char *buf;

ENTRY;

@@ -1255,15 +1258,18 @@
return f;
}

+ buf = kmalloc(PRESTO_COPY_KML_TAIL_BUFSIZE, GFP_KERNEL);
+ if (!buf)
+ return ERR_PTR(-ENOMEM);
+
write_off = 0;
read_off = start;
bytes = fset->fset_kml.fd_offset - start;
while (bytes > 0) {
- char buf[4096];
int toread;

- if (bytes > sizeof(buf))
- toread = sizeof(buf);
+ if (bytes > PRESTO_COPY_KML_TAIL_BUFSIZE)
+ toread = PRESTO_COPY_KML_TAIL_BUFSIZE;
else
toread = bytes;

@@ -1274,6 +1280,7 @@

if (presto_fwrite(f, buf, len, &write_off) != len) {
filp_close(f, NULL);
+ kfree(buf);
EXIT;
return ERR_PTR(-EIO);
}
@@ -1281,6 +1288,7 @@
bytes -= len;
}

+ kfree(buf);
EXIT;
return f;
}
@@ -1584,12 +1592,14 @@
return error;
}

+/* FIXME: should the below go into some header file? */
+#define PRESTO_GET_FILEID_BUFSIZE 4096
int presto_get_fileid(int minor, struct presto_file_set *fset,
struct dentry *dentry)
{
int opcode = KML_OPCODE_GET_FILEID;
struct rec_info rec;
- char *buffer, *path, *logrecord, record[4096]; /*include path*/
+ char *buffer, *path, *logrecord, *record; /*include path*/
struct dentry *root;
__u32 uid, gid, pathlen;
int error, size;
@@ -1597,6 +1607,10 @@

ENTRY;

+ record = kmalloc(PRESTO_GET_FILEID_BUFSIZE, GFP_KERNEL);
+ if (!record)
+ return -ENOMEM;
+
root = fset->fset_dentry;

uid = cpu_to_le32(dentry->d_inode->i_uid);
@@ -1610,7 +1624,7 @@
sizeof(struct kml_suffix);

CDEBUG(D_FILE, "kml size: %d\n", size);
- if ( size > sizeof(record) )
+ if ( size > PRESTO_GET_FILEID_BUFSIZE )
CERROR("InterMezzo: BUFFER OVERFLOW in %s!\n", __FUNCTION__);

memset(&rec, 0, sizeof(rec));
@@ -1633,6 +1647,7 @@
fset->fset_name);

BUFF_FREE(buffer);
+ kfree(record);
EXIT;
return error;
}
-
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