From: Yinghai Lu <yinghai@kernel.org> To: Vineet Gupta <Vineet.Gupta1@synopsys.com>, "H. Peter Anvin" <hpa@zytor.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Chris Zankel <chris@zankel.net>, Max Filippov <jcmvbkbc@gmail.com>, Marc Gauthier <marc@tensilica.com>, Tejun Heo <tj@kernel.org>, Wanpeng Li <liwanp@linux.vnet.ibm.com>, Ingo Molnar <mingo@kernel.org>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] memblock: add assertion for zero allocation size Date: Thu, 21 Feb 2013 11:27:16 -0800 [thread overview] Message-ID: <CAE9FiQXSPHjRsCWcHpz7s1gQjNGuj5_X_YE2Ln=EA7_-Ka_cNg@mail.gmail.com> (raw) In-Reply-To: <1361471962-25164-2-git-send-email-vgupta@synopsys.com> [+Cc: hpa] On Thu, Feb 21, 2013 at 10:39 AM, Vineet Gupta <Vineet.Gupta1@synopsys.com> wrote: > This came to light when calling memblock allocator from arc port (for > copying flattended DT). If a "0" alignment is passed, the allocator > round_up() call incorrectly rounds up the size to 0. > > round_up(num, alignto) => ((num - 1) | (alignto -1)) + 1 > > While the obvious allocation failure causes kernel to panic, it is > better to BUG_ON() if effective size for allocation (as passed by caller > and/or computed after alignemtn rounding) is zero. should we just make align to 1 instead of 0 ? or BUG_ON(!align) instead? > > Signed-off-by: Vineet Gupta <vgupta@synopsys.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Tejun Heo <tj@kernel.org> > Cc: Yinghai Lu <yinghai@kernel.org> > Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > mm/memblock.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index 1bcd9b9..32b36d0 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -824,6 +824,8 @@ static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size, > /* align @size to avoid excessive fragmentation on reserved array */ > size = round_up(size, align); > > + BUG_ON(!size); > + > found = memblock_find_in_range_node(0, max_addr, size, align, nid); > if (found && !memblock_reserve(found, size)) > return found; > -- > 1.7.4.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
WARNING: multiple messages have this Message-ID (diff)
From: Yinghai Lu <yinghai@kernel.org> To: Vineet Gupta <Vineet.Gupta1@synopsys.com>, "H. Peter Anvin" <hpa@zytor.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Chris Zankel <chris@zankel.net>, Max Filippov <jcmvbkbc@gmail.com>, Marc Gauthier <marc@tensilica.com>, Tejun Heo <tj@kernel.org>, Wanpeng Li <liwanp@linux.vnet.ibm.com>, Ingo Molnar <mingo@kernel.org>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] memblock: add assertion for zero allocation size Date: Thu, 21 Feb 2013 11:27:16 -0800 [thread overview] Message-ID: <CAE9FiQXSPHjRsCWcHpz7s1gQjNGuj5_X_YE2Ln=EA7_-Ka_cNg@mail.gmail.com> (raw) In-Reply-To: <1361471962-25164-2-git-send-email-vgupta@synopsys.com> [+Cc: hpa] On Thu, Feb 21, 2013 at 10:39 AM, Vineet Gupta <Vineet.Gupta1@synopsys.com> wrote: > This came to light when calling memblock allocator from arc port (for > copying flattended DT). If a "0" alignment is passed, the allocator > round_up() call incorrectly rounds up the size to 0. > > round_up(num, alignto) => ((num - 1) | (alignto -1)) + 1 > > While the obvious allocation failure causes kernel to panic, it is > better to BUG_ON() if effective size for allocation (as passed by caller > and/or computed after alignemtn rounding) is zero. should we just make align to 1 instead of 0 ? or BUG_ON(!align) instead? > > Signed-off-by: Vineet Gupta <vgupta@synopsys.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Tejun Heo <tj@kernel.org> > Cc: Yinghai Lu <yinghai@kernel.org> > Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > mm/memblock.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index 1bcd9b9..32b36d0 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -824,6 +824,8 @@ static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size, > /* align @size to avoid excessive fragmentation on reserved array */ > size = round_up(size, align); > > + BUG_ON(!size); > + > found = memblock_find_in_range_node(0, max_addr, size, align, nid); > if (found && !memblock_reserve(found, size)) > return found; > -- > 1.7.4.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2013-02-21 19:27 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <1361471962-25164-1-git-send-email-vgupta@synopsys.com> 2013-02-21 18:39 ` [PATCH 1/2] memblock: add assertion for zero allocation size Vineet Gupta 2013-02-21 18:39 ` Vineet Gupta 2013-02-21 19:27 ` Yinghai Lu [this message] 2013-02-21 19:27 ` Yinghai Lu 2013-02-21 19:33 ` Vineet Gupta 2013-02-21 19:33 ` Vineet Gupta 2013-02-21 19:36 ` Tejun Heo 2013-02-21 19:36 ` Tejun Heo 2013-02-21 19:43 ` Vineet Gupta 2013-02-21 19:43 ` Vineet Gupta 2013-02-21 20:10 ` [PATCH v2 1/2] memblock: add assertion for zero allocation alignment Vineet Gupta 2013-02-21 20:10 ` Vineet Gupta 2013-02-21 20:31 ` Yinghai Lu 2013-02-21 20:31 ` Yinghai Lu 2013-02-21 20:47 ` Vineet Gupta 2013-02-21 20:47 ` Vineet Gupta 2013-02-21 20:52 ` [PATCH v3 " Vineet Gupta 2013-02-21 20:52 ` Vineet Gupta 2013-02-21 20:53 ` Tejun Heo 2013-02-21 20:53 ` Tejun Heo 2013-03-04 11:15 ` Vineet Gupta 2013-03-04 11:15 ` Vineet Gupta 2013-02-21 18:39 ` [PATCH 2/2] xtensa: Flat DeviceTree copy not future-safe Vineet Gupta 2013-02-21 20:06 ` Max Filippov 2013-05-29 13:10 ` Fwd: " Vineet Gupta 2013-05-31 1:01 ` Max Filippov
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