From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Al Viro <viro@zeniv.linux.org.uk>,
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 <linux-arm-kernel@lists.infradead.org>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-arch <linux-arch@vger.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Kostya Serebryany <kcc@google.com>,
eugenis@google.com, Lee.Smith@arm.com,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Jacob.Bramley@arm.com, Ruben.Ayrapetyan@arm.com,
cpandya@codeaurora.org
Subject: Re: [PATCH v6 11/11] arm64: annotate user pointers casts detected by sparse
Date: Thu, 6 Sep 2018 14:16:19 -0700 [thread overview]
Message-ID: <CA+55aFy2t_MHgr_CgwbhtFkL+djaCq2qMM1G+f2DwJ0qEr1URQ@mail.gmail.com> (raw)
In-Reply-To: <CA+55aFyW9N2tSb2bQvkthbVVyY6nt5yFeWQRLHp1zruBmb5ocw@mail.gmail.com>
On Thu, Sep 6, 2018 at 2:13 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> So for example:
>
> > static inline compat_uptr_t ptr_to_compat(void __user *uptr)
> > {
> > - return (u32)(unsigned long)uptr;
> > + return (u32)(__force unsigned long)uptr;
> > }
>
> this actually looks correct.
Side note: I do think that while the above is correct, the rest of the
patch shows that we might be better off simply not havign the warning
for address space changes at all for the "cast a pointer to an integer
type" case.
When you cast to a non-pointer type, the address space issue simply
doesn't exist at all, so the warning makes less sense.
It's really just he "pointer to one address space" being cast to
"pointer to another address space" that should really warn, and that
might need that "__force" thing.
Hmm? So maybe a sparse change is better for most of that patch.
Linus
next prev parent reply other threads:[~2018-09-06 21:16 UTC|newest]
Thread overview: 34+ 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 ` [PATCH v6 01/11] arm64: add type casts to untagged_addr macro 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 ` [PATCH v6 03/11] arm64: untag user addresses in access_ok and __uaccess_mask_ptr 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 ` [PATCH v6 05/11] lib, arm64: untag addrs passed to strncpy_from_user and strnlen_user 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 ` [PATCH v6 07/11] fs, arm64: untag user address in copy_mount_options 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 ` [PATCH v6 09/11] arm64: update Documentation/arm64/tagged-pointers.txt 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 ` [PATCH v6 11/11] arm64: annotate user pointers casts detected by sparse Andrey Konovalov
2018-08-31 8:11 ` Luc Van Oostenryck
2018-08-31 13:42 ` Al Viro
2018-09-03 12:34 ` Andrey Konovalov
2018-09-03 13:49 ` Vincenzo Frascino
2018-09-03 15:10 ` Luc Van Oostenryck
2018-09-04 11:27 ` Vincenzo Frascino
2018-09-05 19:03 ` Luc Van Oostenryck
2018-09-06 14:13 ` Vincenzo Frascino
2018-09-06 20:10 ` Luc Van Oostenryck
2018-09-03 13:56 ` Al Viro
2018-09-06 21:13 ` Linus Torvalds
2018-09-06 21:16 ` Linus Torvalds [this message]
2018-09-06 23:08 ` Luc Van Oostenryck
2018-09-07 15:26 ` Catalin Marinas
2018-09-07 16:30 ` Linus Torvalds
2018-09-11 16:41 ` Catalin Marinas
2018-09-17 17:01 ` Andrey Konovalov
2018-09-24 15:04 ` Andrey Konovalov
2018-09-28 17:50 ` Catalin Marinas
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
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