From: Christoph Hellwig <hch@infradead.org>
To: Ruihan Li <lrh2000@pku.edu.cn>
Cc: syzbot+fcf1a817ceb50935ce99@syzkaller.appspotmail.com,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, pasha.tatashin@soleen.com,
gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: usbdev_mmap causes type confusion in page_table_check
Date: Tue, 9 May 2023 06:25:42 -0700 [thread overview]
Message-ID: <ZFpJ1rs+XinCYfPs@infradead.org> (raw)
In-Reply-To: <20230507135844.1231056-1-lrh2000@pku.edu.cn>
On Sun, May 07, 2023 at 09:58:44PM +0800, Ruihan Li wrote:
> static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
> {
> // ...
> mem = usb_alloc_coherent(ps->dev, size, GFP_USER | __GFP_NOWARN,
> &dma_handle);
> // ...
> if (hcd->localmem_pool || !hcd_uses_dma(hcd)) {
> if (remap_pfn_range(vma, vma->vm_start,
> virt_to_phys(usbm->mem) >> PAGE_SHIFT,
usb_alloc_coherent and up in the DMA coherent allocator (usually
anyway), and you absolutely must never do a virt_to_phys or virt_to_page
on that return value. This code is a buggy as f**k.
next prev parent reply other threads:[~2023-05-09 13:25 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-05 0:46 [syzbot] [mm?] kernel BUG in page_table_check_clear syzbot
2023-05-07 13:58 ` usbdev_mmap causes type confusion in page_table_check Ruihan Li
2023-05-08 21:27 ` Pasha Tatashin
2023-05-08 21:36 ` Matthew Wilcox
2023-05-08 21:48 ` Pasha Tatashin
2023-05-08 21:52 ` Matthew Wilcox
2023-05-08 21:55 ` Pasha Tatashin
2023-05-08 22:46 ` David Hildenbrand
2023-05-08 23:17 ` Pasha Tatashin
2023-05-08 23:21 ` Pasha Tatashin
2023-05-08 23:37 ` David Hildenbrand
2023-05-09 0:07 ` Pasha Tatashin
2023-05-08 21:37 ` David Hildenbrand
2023-05-09 13:25 ` Christoph Hellwig [this message]
2023-05-09 14:01 ` Greg KH
2023-05-10 13:17 ` Christoph Hellwig
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