From: Segher Boessenkool <segher@kernel.crashing.org>
To: Daniel Axtens <dja@axtens.net>
Cc: linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v1 01/15] powerpc/uaccess: Remove __get_user_allowed() and unsafe_op_wrap()
Date: Mon, 1 Mar 2021 16:31:09 -0600 [thread overview]
Message-ID: <20210301223108.GE29191@gate.crashing.org> (raw)
In-Reply-To: <87im6ao7ld.fsf@dja-thinkpad.axtens.net>
On Tue, Mar 02, 2021 at 09:02:54AM +1100, Daniel Axtens wrote:
> Checkpatch does have one check that is relevant:
>
> CHECK: Macro argument reuse 'p' - possible side-effects?
> #36: FILE: arch/powerpc/include/asm/uaccess.h:482:
> +#define unsafe_get_user(x, p, e) do { \
> + if (unlikely(__get_user_nocheck((x), (p), sizeof(*(p)), false)))\
> + goto e; \
> +} while (0)
sizeof (of something other than a VLA) does not evaluate its operand.
The checkpatch warning is incorrect (well, it does say "possible" --
it just didn't find a possible problem here).
You can write
bla = sizeof *p++;
and p is *not* incremented.
Segher
next prev parent reply other threads:[~2021-03-01 22:37 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 17:50 [PATCH v1 00/15] powerpc: Cleanup of uaccess.h Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 01/15] powerpc/uaccess: Remove __get_user_allowed() and unsafe_op_wrap() Christophe Leroy
2021-03-01 22:02 ` Daniel Axtens
2021-03-01 22:31 ` Segher Boessenkool [this message]
2021-03-10 8:14 ` Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 02/15] powerpc/uaccess: Define ___get_user_instr() for ppc32 Christophe Leroy
2021-03-01 22:20 ` Daniel Axtens
2021-02-25 17:50 ` [PATCH v1 03/15] powerpc/uaccess: Remove __get/put_user_inatomic() Christophe Leroy
2021-03-01 22:42 ` Daniel Axtens
2021-03-10 8:03 ` Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 04/15] powerpc/uaccess: Move get_user_instr helpers in asm/inst.h Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 05/15] powerpc/align: Don't use __get_user_instr() on kernel addresses Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 06/15] powerpc/uaccess: Call might_fault() inconditionaly Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 07/15] powerpc/uaccess: Remove __unsafe_put_user_goto() Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 08/15] powerpc/uaccess: Remove __chk_user_ptr() in __get/put_user Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 09/15] powerpc/uaccess: Remove calls to __get_user_bad() and __put_user_bad() Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 10/15] powerpc/uaccess: Split out __get_user_nocheck() Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 11/15] powerpc/uaccess: Rename __get/put_user_check/nocheck Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 12/15] powerpc/uaccess: Refactor get/put_user() and __get/put_user() Christophe Leroy
2021-03-07 10:23 ` kernel test robot
2021-03-08 12:14 ` Christophe Leroy
2021-03-08 14:43 ` Christian König
2021-02-25 17:50 ` [PATCH v1 13/15] powerpc/uaccess: Swap clear_user() and __clear_user() Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 14/15] powerpc/uaccess: Also perform 64 bits copies in unsafe_copy_to_user() on ppc32 Christophe Leroy
2021-02-25 17:50 ` [PATCH v1 15/15] powerpc/uaccess: Move copy_mc_xxx() functions down Christophe Leroy
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