From: Matthew Wilcox <willy@infradead.org>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-kernel@vger.kernel.org, "Jens Axboe" <axboe@kernel.dk>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Toralf Förster" <toralf.foerster@gmx.de>,
linux-mm@kvack.org
Subject: Re: [RFC PATCH 1/2] log2: handle LARGE input to __roundup_pow_of_two()
Date: Sun, 20 Dec 2020 21:23:20 +0000 [thread overview]
Message-ID: <20201220212320.GA15600@casper.infradead.org> (raw)
In-Reply-To: <20201220211037.1354-1-rdunlap@infradead.org>
On Sun, Dec 20, 2020 at 01:10:37PM -0800, Randy Dunlap wrote:
> UBSAN detected a 64-bit shift in log2.h:__roundup_pow_of_two():
> UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
> shift exponent 64 is too large for 64-bit type 'long unsigned int'
>
> This is during a call from mm/readahead.c:ondemand_readahead(),
> get_init_ra_size(), where the 'size' parameter must have been
> extremely large (or "negative").
Actually, I think it was zero, which is the real bug that should be fixed.
next prev parent reply other threads:[~2020-12-20 21:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-20 21:10 [RFC PATCH 1/2] log2: handle LARGE input to __roundup_pow_of_two() Randy Dunlap
2020-12-20 21:23 ` Matthew Wilcox [this message]
2020-12-20 22:19 ` Randy Dunlap
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201220212320.GA15600@casper.infradead.org \
--to=willy@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=rdunlap@infradead.org \
--cc=toralf.foerster@gmx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).