Re: [TRIVIAL] Error checks omitted in init_tmpfs() in mm/tiny-shmem.c

[Hareesh Nagarajan <hnagar2@gmail.com>]

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Matt Mackall wrote:
> On Mon, Oct 24, 2005 at 12:29:45AM -0500, Hareesh Nagarajan wrote:
>> The existing code in init_tmpfs() in mm/tiny-shmem.c does not handle the 
>> cases when the calls to register_filesystem() and kern_mount() fail. 
>> This patch adds those checks.
> 
> Hmm. Did you actually encounter this?

No, I haven't. I was just reading the source code when I chanced upon 
these trivial error checking omissions.

> I'd rather use BUG_ON. Passing up errors is only useful when the code
> above can and will do something useful with the information. 

[ Snip ]

> And what could the higher level, which is simply looping through init
> functions, do to handle the error? Retry? Print a warning? Better to
> stop everything outright when we encounter a problem we expect should
> never happen so it doesn't go by undiagnosed.

Makes sense. New patch attached.

Signed-off-by: Hareesh Nagarajan <hnagar2@gmail.com>

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--- linux-2.6.13.4/mm/tiny-shmem.c	2005-10-10 13:54:29.000000000 -0500
+++ linux-2.6.13.4-edit/mm/tiny-shmem.c	2005-10-24 03:43:38.614071000 -0500
@@ -31,12 +31,18 @@
 
 static int __init init_tmpfs(void)
 {
-	register_filesystem(&tmpfs_fs_type);
+	int error;
+
+	error = register_filesystem(&tmpfs_fs_type);
+	BUG_ON(error);
+
 #ifdef CONFIG_TMPFS
 	devfs_mk_dir("shm");
 #endif
 	shm_mnt = kern_mount(&tmpfs_fs_type);
-	return 0;
+	BUG_ON(IS_ERR(shm_mnt));
+
+	return error;
 }
 module_init(init_tmpfs)