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From: Jeffin Philip <jeffinphilip14@gmail.com>
To: gregkh@linuxfoundation.org
Cc: christophe.jaillet@wanadoo.fr, felipe.balbi@linux.intel.com,
	jeffinphilip14@gmail.com, kees@kernel.org,
	linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
	stable@vger.kernel.org,
	syzbot+791be35f1fbcc85d06d7@syzkaller.appspotmail.com
Subject: Re: [PATCH] usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()
Date: Mon, 17 Aug 2026 18:32:08 +0530	[thread overview]
Message-ID: <20260817130208.17219-1-jeffinphilip14@gmail.com> (raw)
In-Reply-To: <2026081701-glitzy-hush-b284@gregkh>

On Mon, 17 Aug 2026 13:10:27 +0200, Greg KH wrote:
>But that is probably a bad idea, right?  Shouldn't we fix that error
>first?

Thanks for the review. Don't quite understand what I need to fix here
(respectfully), should we harden the buffhds null check to include 
ZERO_SIZE_PTRs too, something like this should suffice?:

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 640d3bcb7bf0..98643d53cc7a 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -2747,11 +2747,11 @@ int fsg_common_set_num_buffers(struct fsg_common *common, unsigned int n)
 	struct fsg_buffhd *bh, *buffhds;
 	int i;
  
 	buffhds = kzalloc_objs(*buffhds, n);
-	if (!buffhds)
+	if (ZERO_OR_NULL_PTR(buffhds))
 		return -ENOMEM;
 
 	/* Data buffers cyclic list */

Thanks,
Jeffin.

  reply	other threads:[~2026-08-17 13:02 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-17 11:08 Jeffin Philip
2026-08-17 11:10 ` Greg KH
2026-08-17 13:02   ` Jeffin Philip [this message]
2026-08-17 13:15     ` Greg KH
2026-08-17 14:01 ` Alan Stern
2026-08-17 16:03   ` Jeffin Philip
2026-08-17 16:09     ` Jeffin Philip
2026-08-17 16:49       ` Alan Stern

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