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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
> Sent: 22 October 2020 14:51

I'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.
There are no references to w24, just x24.
So the kmalloc_array() is passed 'huge' and will fail.
The iov_iter_init also gets the 64bit value.

Note that the gcc code has a sign-extend copy of w2.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)






[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux