From: Al Viro <viro@ZenIV.linux.org.uk>
To: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Kees Cook <keescook@chromium.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Shuah Khan <shuah@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
Dmitry Vyukov <dvyukov@google.com>,
Kostya Serebryany <kcc@google.com>, Evgeniy Stepanov <eugenis@>
Subject: Re: [PATCH v6 11/11] arm64: annotate user pointers casts detected by sparse
Date: Fri, 31 Aug 2018 14:42:44 +0100 [thread overview]
Message-ID: <20180831134244.GB19965@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180831081123.6mo62xnk54pvlxmc@ltop.local>
On Fri, Aug 31, 2018 at 10:11:24AM +0200, Luc Van Oostenryck wrote:
> On Thu, Aug 30, 2018 at 01:41:16PM +0200, Andrey Konovalov wrote:
> > This patch adds __force annotations for __user pointers casts detected by
> > sparse with the -Wcast-from-as flag enabled (added in [1]).
> >
> > [1] https://github.com/lucvoo/sparse-dev/commit/5f960cb10f56ec2017c128ef9d16060e0145f292
>
> Hi,
>
> It would be nice to have some explanation for why these added __force
> are useful.
It would be even more useful if that series would either deal with
the noise for real ("that's what we intend here, that's what we intend there,
here's a primitive for such-and-such kind of cases, here we actually
ought to pass __user pointer instead of unsigned long", etc.) or left it
unmasked.
As it is, __force says only one thing: "I know the code is doing
the right thing here". That belongs in primitives, and I do *not* mean the
#define cast_to_ulong(x) ((__force unsigned long)(x))
kind.
Folks, if you don't want to deal with that - leave the warnings be.
They do carry more information than "someone has slapped __force in that place".
Al, very annoyed by that kind of information-hiding crap...
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Kees Cook <keescook@chromium.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Shuah Khan <shuah@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
Dmitry Vyukov <dvyukov@google.com>,
Kostya Serebryany <kcc@google.com>,
Evgeniy Stepanov <eugenis@google.com>,
Lee Smith <Lee.Smith@arm.com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Jacob Bramley <Jacob.Bramley@arm.com>,
Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
Chintan Pandya <cpandya@codeaurora.org>
Subject: Re: [PATCH v6 11/11] arm64: annotate user pointers casts detected by sparse
Date: Fri, 31 Aug 2018 14:42:44 +0100 [thread overview]
Message-ID: <20180831134244.GB19965@ZenIV.linux.org.uk> (raw)
Message-ID: <20180831134244.znW9hVyOQ5VPaQT3pYRGdidUUU6c3BAexPFMwlRSRUM@z> (raw)
In-Reply-To: <20180831081123.6mo62xnk54pvlxmc@ltop.local>
On Fri, Aug 31, 2018 at 10:11:24AM +0200, Luc Van Oostenryck wrote:
> On Thu, Aug 30, 2018 at 01:41:16PM +0200, Andrey Konovalov wrote:
> > This patch adds __force annotations for __user pointers casts detected by
> > sparse with the -Wcast-from-as flag enabled (added in [1]).
> >
> > [1] https://github.com/lucvoo/sparse-dev/commit/5f960cb10f56ec2017c128ef9d16060e0145f292
>
> Hi,
>
> It would be nice to have some explanation for why these added __force
> are useful.
It would be even more useful if that series would either deal with
the noise for real ("that's what we intend here, that's what we intend there,
here's a primitive for such-and-such kind of cases, here we actually
ought to pass __user pointer instead of unsigned long", etc.) or left it
unmasked.
As it is, __force says only one thing: "I know the code is doing
the right thing here". That belongs in primitives, and I do *not* mean the
#define cast_to_ulong(x) ((__force unsigned long)(x))
kind.
Folks, if you don't want to deal with that - leave the warnings be.
They do carry more information than "someone has slapped __force in that place".
Al, very annoyed by that kind of information-hiding crap...
next prev parent reply other threads:[~2018-08-31 13:42 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-30 11:41 [PATCH v6 00/11] arm64: untag user pointers passed to the kernel Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 01/11] arm64: add type casts to untagged_addr macro Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 02/11] uaccess: add untagged_addr definition for other arches Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 03/11] arm64: untag user addresses in access_ok and __uaccess_mask_ptr Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 04/11] mm, arm64: untag user addresses in mm/gup.c Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 05/11] lib, arm64: untag addrs passed to strncpy_from_user and strnlen_user Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 06/11] arm64: untag user address in __do_user_fault Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 07/11] fs, arm64: untag user address in copy_mount_options Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 08/11] usb, arm64: untag user addresses in devio Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 09/11] arm64: update Documentation/arm64/tagged-pointers.txt Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 10/11] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-30 11:41 ` [PATCH v6 11/11] arm64: annotate user pointers casts detected by sparse Andrey Konovalov
2018-08-30 11:41 ` Andrey Konovalov
2018-08-31 8:11 ` Luc Van Oostenryck
2018-08-31 8:11 ` Luc Van Oostenryck
2018-08-31 13:42 ` Al Viro [this message]
2018-08-31 13:42 ` Al Viro
2018-09-03 12:34 ` Andrey Konovalov
2018-09-03 12:34 ` Andrey Konovalov
2018-09-03 13:49 ` Vincenzo Frascino
2018-09-03 13:49 ` Vincenzo Frascino
2018-09-03 15:10 ` Luc Van Oostenryck
2018-09-03 15:10 ` Luc Van Oostenryck
2018-09-04 11:27 ` Vincenzo Frascino
2018-09-04 11:27 ` Vincenzo Frascino
2018-09-05 19:03 ` Luc Van Oostenryck
2018-09-05 19:03 ` Luc Van Oostenryck
2018-09-06 14:13 ` Vincenzo Frascino
2018-09-06 14:13 ` Vincenzo Frascino
2018-09-06 20:10 ` Luc Van Oostenryck
2018-09-06 20:10 ` Luc Van Oostenryck
2018-09-03 13:56 ` Al Viro
2018-09-03 13:56 ` Al Viro
2018-09-06 21:13 ` Linus Torvalds
2018-09-06 21:13 ` Linus Torvalds
2018-09-06 21:16 ` Linus Torvalds
2018-09-06 21:16 ` Linus Torvalds
2018-09-06 23:08 ` Luc Van Oostenryck
2018-09-06 23:08 ` Luc Van Oostenryck
2018-09-07 15:26 ` Catalin Marinas
2018-09-07 15:26 ` Catalin Marinas
2018-09-07 16:30 ` Linus Torvalds
2018-09-07 16:30 ` Linus Torvalds
2018-09-11 16:41 ` Catalin Marinas
2018-09-11 16:41 ` Catalin Marinas
2018-09-17 17:01 ` Andrey Konovalov
2018-09-17 17:01 ` Andrey Konovalov
2018-09-24 15:04 ` Andrey Konovalov
2018-09-24 15:04 ` Andrey Konovalov
2018-09-28 17:50 ` Catalin Marinas
2018-09-28 17:50 ` Catalin Marinas
2018-10-02 13:19 ` Andrey Konovalov
2018-10-02 13:19 ` Andrey Konovalov
2018-09-14 1:25 ` [LKP] [arm64] 7b5b51e7b3: kvm-unit-tests.rmap_chain.fail kernel test robot
2018-08-30 11:48 ` [PATCH v6 00/11] arm64: untag user pointers passed to the kernel Andrey Konovalov
2018-08-30 11:48 ` Andrey Konovalov
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