From: Christoph Hellwig <hch@lst.de>
To: syzbot <syzbot+b4bfacdec173efaa8567@syzkaller.appspotmail.com>
Cc: hch@lst.de, iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
m.szyprowski@samsung.com, robin.murphy@arm.com,
syzkaller-bugs@googlegroups.com,
Sean Anderson <sean.anderson@linux.dev>
Subject: Re: [syzbot] [iommu?] kernel BUG in dma_alloc_attrs
Date: Wed, 16 Oct 2024 10:02:40 +0200 [thread overview]
Message-ID: <20241016080240.GA30380@lst.de> (raw)
In-Reply-To: <670ebde5.050a0220.d9b66.0154.GAE@google.com>
The problem is that the dma alloc/free tracing calls virt_to_phys
on the allocated/free memory. But that memory can be vmalloced as
in this case. I think we don't have weirdo allocators or pools any
more that are neither in the direct kernel mapping or vmalloc, so
we might be able to do an
if (is_vmalloc_addr())
page_to_phys(vmalloc_to_page()))
else
virt_to_page()
here. Or just switch to tracing the virtual address to always be
on the safe side.
next prev parent reply other threads:[~2024-10-16 8:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-15 19:09 [syzbot] [iommu?] kernel BUG in dma_alloc_attrs syzbot
2024-10-16 8:02 ` Christoph Hellwig [this message]
2024-10-17 14:31 ` Sean Anderson
2024-10-17 14:40 ` Christoph Hellwig
2024-10-17 14:48 ` Sean Anderson
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