RE: Buggy commit tracked to: "Re: [PATCH 2/9] iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c"

From
David Laight <hidden>
Date
2020-11-02 09:08:10
Also in
io-uring, keyrings, linux-arch, linux-arm-kernel, linux-block, linux-fsdevel, linux-mips, linux-mm, linux-s390, linux-scsi, linux-security-module, linuxppc-dev, lkml, sparclinux
Reply to
'Greg KH', 2020-10-23
From: 'Greg KH'
Sent: 23 October 2020 15:47

On Fri, Oct 23, 2020 at 02:39:24PM +0000, David Laight wrote:
quoted
From: David Hildenbrand
quoted
Sent: 23 October 2020 15:33
...
quoted
I just checked against upstream code generated by clang 10 and it
properly discards the upper 32bit via a mov w23 w2.

So at least clang 10 indeed properly assumes we could have garbage and
masks it off.

Maybe the issue is somewhere else, unrelated to nr_pages ... or clang 11
behaves differently.
We'll need the disassembly from a failing kernel image.
It isn't that big to hand annotate.
I've worked around the merge at the moment in the android tree, but it
is still quite reproducable, and will try to get a .o file to
disassemble on Monday or so...
Did this get properly resolved?

	David

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Thread (54 messages) 54 messages, 9 authors, last reply 2020-11-02
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