Re: [PATCH] fix stack usage in fs/intermezzo/journal.c

Joern Engel (joern@wohnheim.fh-wedel.de)
Fri, 14 Mar 2003 17:44:45 +0100


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; } - 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/