linux-kernel - Re: [PATCH v2] ras: cec: Fix debugfs error checking

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20251120122222.GAaR8H_iCA0YxuyUvN@fat_crate.local>
Date: Thu, 20 Nov 2025 13:22:22 +0100
From: Borislav Petkov <bp@...en8.de>
To: Haotian Zhang <vulab@...as.ac.cn>
Cc: tony.luck@...el.com, qiuxu.zhuo@...el.com, linux-edac@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] ras: cec: Fix debugfs error checking

On Thu, Nov 20, 2025 at 04:07:08PM +0800, Haotian Zhang wrote:
> The debugfs_create_dir() and debugfs_create_file() functions return
> ERR_PTR() on error, not NULL. The current null-checks fail to detect
> errors because ERR_PTR() encodes error codes as non-null pointer values.
> 
> Replace the null-checks with IS_ERR() for all debugfs_create_dir() and
> debugfs_create_file() and ras_get_debugfs_root calls to properly
> handle errors.
> 
> Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector")

git show 011d82611172:fs/debugfs/inode.c
...
struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
{
        struct dentry *dentry = start_creating(name, parent);
        struct inode *inode;
 
        if (IS_ERR(dentry))
                return NULL;
		^^^^^^^^^^^

So it used to return NULL at the time.

However,

/**     
 * debugfs_create_file - create a file in the debugfs filesystem

	...

 * NOTE: it's expected that most callers should _ignore_ the errors returned
 * by this function. Other debugfs functions handle the fact that the "dentry"
 * passed to them could be an error and they don't crash in that case.
 * Drivers should generally work fine even if debugfs fails to init anyway.
 */

and the _dir() one has the same note. I've been hesitant to remove that error
handling in cec.c until now but I think we can safely zap it. It is
unnecessary clutter by now.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette