Re: Buggy commit tracked to: "Re: [PATCH 2/9] iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c"
From: Arnd Bergmann <arnd@arndb.de>
Date: 2020-10-23 13:23:45
Also in:
linux-mm
On Fri, Oct 23, 2020 at 2:46 PM David Laight [off-list ref] wrote:
From: Greg KH <gregkh@linuxfoundation.org>quoted
Sent: 22 October 2020 14:51I've rammed the code into godbolt. https://godbolt.org/z/9v5PPW Definitely a clang bug. Search for [wx]24 in the clang output. nr_segs comes in as w2 and the initial bound checks are done on w2. w24 is loaded from w2 - I don't believe this changes the high bits.
You believe wrong, "mov w24, w2" is a zero-extending operation.
Arnd