From: Thomas Gleixner <tglx@linutronix.de>
To: Uros Bizjak <ubizjak@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
kernel test robot <lkp@intel.com>,
oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org,
Arjan van de Ven <arjan@linux.intel.com>,
x86@kernel.org, Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Sparse Mailing-list <linux-sparse@vger.kernel.org>
Subject: Re: arch/x86/include/asm/processor.h:698:16: sparse: sparse: incorrect type in initializer (different address spaces)
Date: Sun, 03 Mar 2024 21:10:50 +0100 [thread overview]
Message-ID: <87bk7vuldh.ffs@tglx> (raw)
In-Reply-To: <CAFULd4bVEUBEidTLbHNzRaJbSjXm99yC8LT=jdzFWb7xnuFH7g@mail.gmail.com>
On Sun, Mar 03 2024 at 20:03, Uros Bizjak wrote:
> On Sun, Mar 3, 2024 at 5:31 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>> I did not follow the __set_gs work closely, so I don't know whether Uros
>> ever tried to actually mark the per CPU variable __set_gs right away,
>> which would obviously catch the above 'foo' nonsense.
>
> No, because [1]:
>
> "gcc does not provide a way to remove segment qualifiers, which is needed
> to use typeof() to create local instances of the per-cpu variable. For
> this reason, do not use the segment qualifier for per-cpu variables, and
> do casting using the segment qualifier instead."
Right. I just figured that out myself when playing with it in user
space.
That's so sad because it would provide us compiler based __percpu
validation.
Right now this simply does not work and __verify_pcp_ptr(ptr) is not
doing anything except when sparse looks at it.
Sigh.
tglx
next prev parent reply other threads:[~2024-03-03 20:10 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-01 20:12 arch/x86/include/asm/processor.h:698:16: sparse: sparse: incorrect type in initializer (different address spaces) kernel test robot
2024-03-01 21:57 ` Thomas Gleixner
2024-03-01 22:26 ` Thomas Gleixner
2024-03-02 9:43 ` Philip Li
2024-03-02 11:37 ` Thomas Gleixner
2024-03-02 15:44 ` Thomas Gleixner
2024-03-02 22:00 ` Thomas Gleixner
2024-03-02 22:49 ` Linus Torvalds
2024-03-03 16:31 ` Thomas Gleixner
2024-03-03 19:03 ` Uros Bizjak
2024-03-03 20:10 ` Thomas Gleixner [this message]
2024-03-03 20:21 ` Uros Bizjak
2024-03-03 20:24 ` Uros Bizjak
2024-03-03 21:19 ` Uros Bizjak
2024-03-03 23:49 ` Thomas Gleixner
2024-03-04 5:42 ` Uros Bizjak
2024-03-04 7:07 ` Thomas Gleixner
2024-04-02 11:43 ` Uros Bizjak
2024-04-03 17:57 ` Nathan Chancellor
2024-04-04 6:56 ` Uros Bizjak
2024-04-29 21:30 ` [RFC PATCH] Use x86 named address spaces to catch "sparse: incorrect type in initializer (different address spaces)" __percpu errors Uros Bizjak
2024-03-02 12:53 ` arch/x86/include/asm/processor.h:698:16: sparse: sparse: incorrect type in initializer (different address spaces) Yujie Liu
-- strict thread matches above, loose matches on Subject: below --
2024-01-09 20:00 kernel test robot
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