Re: + usb-gadgetfs-do-not-warn-about-excessively-large-memory-allocations.patch added to mm-nonmm-unstable branch

["Vlastimil Babka (SUSE)" <vbabka@kernel.org>]

On 8/21/26 00:37, Andrew Morton wrote:
> The patch titled
>      Subject: USB: gadgetfs: do not WARN about excessively large memory allocations
> has been added to the -mm mm-nonmm-unstable branch.  Its filename is
>      usb-gadgetfs-do-not-warn-about-excessively-large-memory-allocations.patch
> 
> This patch will shortly appear at
>      https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/usb-gadgetfs-do-not-warn-about-excessively-large-memory-allocations.patch
> 
> This patch will later appear in the mm-nonmm-unstable branch at
>     git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> 
> Before you just go and hit "reply", please:
>    a) Consider who else should be cc'ed
>    b) Prefer to cc a suitable mailing list as well
>    c) Ideally: find the original patch on the mailing list and do a
>       reply-to-all to that, adding suitable additional cc's
> 
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
> 
> The -mm tree is included into linux-next via various
> branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> and is updated there most days
> 
> ------------------------------------------------------
> From: Zi Yan <ziy@nvidia.com>
> Subject: USB: gadgetfs: do not WARN about excessively large memory allocations
> Date: Thu, 20 Aug 2026 09:19:12 -0400
> 
> GadgetFS passes an excessively large user input len to kmalloc and kmalloc
> gives a WARN (see below for details).  Suppress it by passing __GFP_NOWARN
> to kmalloc used by both ep_write_iter() and ep_read_iter().  Follow the
> same method as commit 4f2629ea67e72 ("USB: usbfs: Don't WARN about
> excessively large memory allocations").
> 
> kmalloc is used to allocate physically contiguous memory for kernel
> allocations.  For requests larger than KMALLOC_MAX_CACHE_SIZE, kmalloc
> uses the page allocator and can only support up to KMALLOC_MAX_SIZE.  For
> request sizes bigger than KMALLOC_MAX_SIZE, the page allocator can emit a
> WARN because kmalloc allocates an order greater than MAX_PAGE_ORDER.
> 
> Link: https://lore.kernel.org/DKTTMAS94IMH.2C6ERY0ZIVWVZ@nvidia.com
> Fixes: b3c466ce5129 ("page allocator: do not sanity check order in the fast=
>  path")
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> Reported-by: syzbot+805630f1453e490427fa@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/all/6a820ebc.9ebadd4d.20b15e.001b.GAE@googl=
> e.com/
> Tested-by: syzbot+805630f1453e490427fa@syzkaller.appspotmail.com
> Acked-by: Alan Stern <stern@rowland.harvard.edu>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Vlastimil Babka <vbabka@kernel.org>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>

> ---
> 
>  drivers/usb/gadget/legacy/inode.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> --- a/drivers/usb/gadget/legacy/inode.c~usb-gadgetfs-do-not-warn-about-excessively-large-memory-allocations
> +++ a/drivers/usb/gadget/legacy/inode.c
> @@ -604,7 +604,7 @@ ep_read_iter(struct kiocb *iocb, struct
>  		return -EBADMSG;
>  	}
>  
> -	buf = kmalloc(len, GFP_KERNEL);
> +	buf = kmalloc(len, GFP_KERNEL | __GFP_NOWARN);
>  	if (unlikely(!buf)) {
>  		mutex_unlock(&epdata->lock);
>  		return -ENOMEM;
> @@ -666,7 +666,7 @@ ep_write_iter(struct kiocb *iocb, struct
>  		return -EBADMSG;
>  	}
>  
> -	buf = kmalloc(len, GFP_KERNEL);
> +	buf = kmalloc(len, GFP_KERNEL | __GFP_NOWARN);
>  	if (unlikely(!buf)) {
>  		mutex_unlock(&epdata->lock);
>  		return -ENOMEM;
> _
> 
> Patches currently in -mm which might be from ziy@nvidia.com are
> 
> mm-huge_memory-use-folios-memcg-inside-__folio_split.patch
> xarray-honor-xa_flags_account-in-xas_split_alloc.patch
> usb-gadgetfs-do-not-warn-about-excessively-large-memory-allocations.patch
>