Re: [PATCH] usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()

From: Jeffin Philip

Date: Mon Aug 17 2026 - 09:07:02 EST


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.