From: Rafael David Tinoco <rafael.tinoco@linaro.org>
To: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Rafael David Tinoco <rafael.tinoco@linaro.org>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
Mark Brown <broonie@kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Nitin Gupta <ngupta@vflare.org>, Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH 1/2] mm/zsmalloc.c: check encoded object value overflow for PAE
Date: Thu, 25 Oct 2018 09:37:59 -0300 [thread overview]
Message-ID: <CABdQkv_cC4ixEFr91zyg-S21O5_7U8FV7=g7ZMRqGcQyhrwzaQ@mail.gmail.com> (raw)
In-Reply-To: <20181025120006.GY30658@n2100.armlinux.org.uk>
> MAX_PHYSMEM_BITS is a definition for sparsemem, and is only visible
> when sparsemem is enabled. When sparsemem is disabled, asm/sparsemem.h
> is not included (and should not be included) which means there is no
> MAX_PHYSMEM_BITS definition.
Missed that part :\, tks.
> I don't think zsmalloc.c should be (ab)using MAX_PHYSMEM_BITS, and
> your description above makes it sound like you expect it to always be
> defined.
>
> If we want to have a definition for this, we shouldn't be playing
> fragile games like:
>
> #ifndef MAX_POSSIBLE_PHYSMEM_BITS
> #ifdef MAX_PHYSMEM_BITS
> #define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS
> #else
> /*
> * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just
> * be PAGE_SHIFT
> */
> #define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG
> #endif
> #endif
>
> but instead insist that MAX_PHYSMEM_BITS is defined _everywhere_.
Is it okay to propose using only MAX_PHYSMEM_BITS for zsmalloc (like
it was before commit 02390b87) instead, and make sure *at least* ARM
32/64 and x86/x64, for now, have it defined outside sparsemem headers
as well ? This way I can WARN_ONCE(), instead of BUG(), when specific
arch does not define it - enforcing behavior - showing BITS_PER_LONG
is being used instead of MAX_PHYSMEM_BITS (warning, at least once, for
the possibility of an overflow, like the issue showed in here).
next prev parent reply other threads:[~2018-10-25 12:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-25 1:27 [PATCH 1/2] mm/zsmalloc.c: check encoded object value overflow for PAE Rafael David Tinoco
2018-10-25 1:27 ` [PATCH 2/2] mm/zsmalloc.c: fix zsmalloc ARM LPAE support Rafael David Tinoco
2018-10-25 5:29 ` [PATCH 1/2] mm/zsmalloc.c: check encoded object value overflow for PAE Sergey Senozhatsky
2018-10-25 11:03 ` Rafael David Tinoco
2018-10-25 12:00 ` Russell King - ARM Linux
2018-10-25 12:37 ` Rafael David Tinoco [this message]
2018-10-25 13:43 ` Russell King - ARM Linux
2018-11-21 0:11 ` [PATCH v2] mm/zsmalloc.c: Fix zsmalloc 32-bit PAE support Rafael David Tinoco
2018-11-21 0:18 ` Rafael David Tinoco
2018-11-27 20:33 ` Rafael David Tinoco
2018-11-29 2:53 ` Sergey Senozhatsky
2018-10-25 12:42 ` [PATCH 1/2] mm/zsmalloc.c: check encoded object value overflow for PAE kbuild test robot
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