All of lore.kernel.org
 help / color / mirror / Atom feed
From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: vbabka@suse.cz, akpm@linux-foundation.org,
	iamjoonsoo.kim@lge.com, rientjes@google.com, penberg@kernel.org,
	cl@linux.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	nathan@kernel.org, naresh.kamboju@linaro.org,
	clang-built-linux@googlegroups.com, linux-next@vger.kernel.org,
	ndesaulniers@google.com, lkft-triage@lists.linaro.org,
	sfr@canb.auug.org.au, arnd@arndb.de, akpm@linux-foundation.org
Subject: Re: [PATCH v3] mm, slub: change run-time assertion in kmalloc_index() to compile-time
Date: Sun, 16 May 2021 06:09:50 +0900	[thread overview]
Message-ID: <20210515210950.GA52841@hyeyoo> (raw)
In-Reply-To: <20210511173448.GA54466@hyeyoo>

Hello Vlastimil, recently kbuild-all test bot reported compile error on
clang 10.0.1, with defconfig.

Nathan Chancellor wrote:
> I think this happens because arch_prepare_optimized_kprobe() calls kzalloc()
> with a size of MAX_OPTINSN_SIZE, which is
> 
> #define MAX_OPTINSN_SIZE                                \
>       (((unsigned long)optprobe_template_end -        \
>          (unsigned long)optprobe_template_entry) +     \
>         MAX_OPTIMIZED_LENGTH + JMP32_INSN_SIZE)

> and the optprobe_template_{end,entry} are not evaluated as constants.
>
> I am not sure what the solution is. There seem to be a growing list of issues
> with LLVM 10 that were fixed in LLVM 11, which might necessitate requiring
> LLVM 11 and newer to build the kernel, given this affects a defconfig.
> Cheers,
> Nathan


I think it's because kmalloc compiles successfully when size is constant,
and kmalloc_index isn't. so I think compiler seems to be confused.

currently if size is non-constant, kmalloc calls dummy function __kmalloc,
which always returns NULL.

so what about changing kmalloc to do compile-time assertion too, and track
all callers that are calling kmalloc with non-constant argument.

How do you think? If you think it is the solution, I'll do that work.

  parent reply	other threads:[~2021-05-15 21:10 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-11 17:34 [PATCH v3] mm, slub: change run-time assertion in kmalloc_index() to compile-time Hyeonggon Yoo
2021-05-11 17:38 ` Hyeonggon Yoo
2021-05-11 18:08 ` Vlastimil Babka
2021-05-13  2:52 ` Andrew Morton
2021-05-13  3:12   ` Hyeonggon Yoo
2021-05-13  3:40     ` Andrew Morton
2021-05-13  6:28       ` Hyeonggon Yoo
2021-05-13  8:46         ` Marco Elver
2021-05-13  8:46           ` Marco Elver
2021-05-13  8:51         ` Vlastimil Babka
2021-05-13 10:31           ` Marco Elver
2021-05-13 11:37             ` Vlastimil Babka
2021-05-13 12:08               ` Hyeonggon Yoo
2021-05-13 12:10                 ` Hyeonggon Yoo
2021-05-13 12:03             ` Hyeonggon Yoo
2021-05-13 12:29               ` Marco Elver
2021-05-13 12:29                 ` Marco Elver
2021-05-13 12:38                 ` Hyeonggon Yoo
2021-05-13 13:08                 ` Hyeonggon Yoo
2021-05-13 12:44   ` [PATCH] kfence: test: fix for "mm, slub: change run-time assertion in kmalloc_index() to compile-time" Marco Elver
2021-05-15 21:09 ` Hyeonggon Yoo [this message]
2021-05-15 21:24   ` [PATCH v3] mm, slub: change run-time assertion in kmalloc_index() to compile-time Vlastimil Babka
2021-05-15 21:56     ` Hyeonggon Yoo
2021-05-16  6:34     ` Nathan Chancellor
2021-05-18  0:38       ` Hyeonggon Yoo
2021-05-18  0:43         ` Nathan Chancellor
2021-05-18  1:53           ` Hyeonggon Yoo
2021-05-18  9:28           ` Vlastimil Babka
2021-05-18 11:18             ` Hyeonggon Yoo
2021-05-18 11:34               ` Vlastimil Babka
2021-05-19  5:45                 ` Hyeonggon Yoo

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=20210515210950.GA52841@hyeyoo \
    --to=42.hyeyoo@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=arnd@arndb.de \
    --cc=cl@linux.com \
    --cc=clang-built-linux@googlegroups.com \
    --cc=iamjoonsoo.kim@lge.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-next@vger.kernel.org \
    --cc=lkft-triage@lists.linaro.org \
    --cc=naresh.kamboju@linaro.org \
    --cc=nathan@kernel.org \
    --cc=ndesaulniers@google.com \
    --cc=penberg@kernel.org \
    --cc=rientjes@google.com \
    --cc=sfr@canb.auug.org.au \
    --cc=vbabka@suse.cz \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.