linux-kernel - Re: [PATCH] x86: endless page faults in mount_block

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Date:	Wed, 23 Apr 2008 02:18:49 +0200
From:	Henry Nestler <Henry.Ne@...or.de>
To:	linux-kernel@...r.kernel.org
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH] x86: endless page faults in mount_block_root for Linux
 2.6

An other fix would be to copy the "fs_names+offset" into a new page and
give a page alignment buffer to do_mount_root. I feel it is better to
fix the fault handler for all failed addresses, not only the mount?

--- linux-2.6.25/init/do_mounts.c
+++ linux-2.6.25/init/do_mounts.c
@@ -204,6 +204,7 @@
 void __init mount_block_root(char *name, int flags)
 {
        char *fs_names = __getname();
+       char *fs_type = __getname();
        char *p;
 #ifdef CONFIG_BLOCK
        char b[BDEVNAME_SIZE];
@@ -214,7 +215,12 @@
        get_fs_names(fs_names);
 retry:
        for (p = fs_names; *p; p += strlen(p)+1) {
-               int err = do_mount_root(name, p, flags, root_mount_data);
+               int err;
+
+               /* fs_type must size >= PAGE_SIZE or in user space */
+               strcpy(fs_type, p);
+
+               err = do_mount_root(name, fs_type, flags, root_mount_data);
                switch (err) {
                        case 0:
                                goto out;
@@ -251,6 +257,7 @@
 #endif
        panic("VFS: Unable to mount root fs on %s", b);
 out:
+       putname(fs_type);
        putname(fs_names);
 }


-- 
Henry N.
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