From: Craig Milo Rogers <rogers@isi.edu>
To: Andrzej Hajda <a.hajda@samsung.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Linux MM <linux-mm@kvack.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andi Kleen <andi@firstfloor.org>, Andreas Mohr <andi@lisas.de>,
Mike Turquette <mturquette@linaro.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/5] kstrdup optimization
Date: Tue, 13 Jan 2015 16:10:57 -0800 [thread overview]
Message-ID: <20150114001057.GA30408@isi.edu> (raw)
In-Reply-To: <CAMuHMdV74n3v81xaLRDN_Mn_QGg14yUkXNn6JYaGH4MGgLRM2A@mail.gmail.com>
> As kfree_const() has the exact same signature as kfree(), the risk of
> accidentally passing pointers returned from kstrdup_const() to kfree() seems
> high, which may lead to memory corruption if the pointer doesn't point to
> allocated memory.
...
>> To verify if the source is in .rodata function checks if the address is between
>> sentinels __start_rodata, __end_rodata. I guess it should work with all
>> architectures.
kfree() could also check if the region being freed is in .rodata, and
ignore the call; kfree_const() would not be needed. If making this check all
the time leads to a significant decrease in performance (numbers needed here),
another option is to keep kfree_const() but add a check to kfree(), when
compiled for debugging, that issues a suitable complaint if the region being
freed is in .rodata.
Craig Milo Rogers
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WARNING: multiple messages have this Message-ID (diff)
From: Craig Milo Rogers <rogers@isi.edu>
To: Andrzej Hajda <a.hajda@samsung.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Linux MM <linux-mm@kvack.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andi Kleen <andi@firstfloor.org>, Andreas Mohr <andi@lisas.de>,
Mike Turquette <mturquette@linaro.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/5] kstrdup optimization
Date: Tue, 13 Jan 2015 16:10:57 -0800 [thread overview]
Message-ID: <20150114001057.GA30408@isi.edu> (raw)
In-Reply-To: <CAMuHMdV74n3v81xaLRDN_Mn_QGg14yUkXNn6JYaGH4MGgLRM2A@mail.gmail.com>
> As kfree_const() has the exact same signature as kfree(), the risk of
> accidentally passing pointers returned from kstrdup_const() to kfree() seems
> high, which may lead to memory corruption if the pointer doesn't point to
> allocated memory.
...
>> To verify if the source is in .rodata function checks if the address is between
>> sentinels __start_rodata, __end_rodata. I guess it should work with all
>> architectures.
kfree() could also check if the region being freed is in .rodata, and
ignore the call; kfree_const() would not be needed. If making this check all
the time leads to a significant decrease in performance (numbers needed here),
another option is to keep kfree_const() but add a check to kfree(), when
compiled for debugging, that issues a suitable complaint if the region being
freed is in .rodata.
Craig Milo Rogers
next prev parent reply other threads:[~2015-01-14 0:11 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-12 9:18 [PATCH 0/5] kstrdup optimization Andrzej Hajda
2015-01-12 9:18 ` Andrzej Hajda
2015-01-12 9:18 ` [PATCH 1/5] mm/util: add kstrdup_const Andrzej Hajda
2015-01-12 9:18 ` Andrzej Hajda
2015-01-12 17:13 ` Joe Perches
2015-01-12 17:13 ` Joe Perches
2015-01-12 9:18 ` [PATCH 2/5] kernfs: convert node name allocation to kstrdup_const Andrzej Hajda
2015-01-12 9:18 ` Andrzej Hajda
2015-01-14 14:13 ` Tejun Heo
2015-01-14 14:13 ` Tejun Heo
2015-01-14 14:37 ` [PATCH 2.5/5] kernfs: remove KERNFS_STATIC_NAME Tejun Heo
2015-01-14 14:37 ` Tejun Heo
2015-01-12 9:18 ` [PATCH 3/5] clk: convert clock name allocations to kstrdup_const Andrzej Hajda
2015-01-12 9:18 ` Andrzej Hajda
2015-01-12 23:11 ` Mike Turquette
2015-01-13 7:57 ` Andrzej Hajda
2015-01-13 7:57 ` Andrzej Hajda
2015-01-12 9:18 ` [PATCH 4/5] mm/slab: convert cache " Andrzej Hajda
2015-01-12 9:18 ` Andrzej Hajda
2015-01-12 9:18 ` [PATCH 5/5] fs/namespace: convert devname allocation " Andrzej Hajda
2015-01-12 9:18 ` Andrzej Hajda
2015-01-12 20:45 ` [PATCH 0/5] kstrdup optimization Geert Uytterhoeven
2015-01-12 20:45 ` Geert Uytterhoeven
2015-01-13 23:48 ` Andrew Morton
2015-01-13 23:48 ` Andrew Morton
2015-01-14 0:10 ` Craig Milo Rogers [this message]
2015-01-14 0:10 ` Craig Milo Rogers
2015-01-14 0:17 ` Andrew Morton
2015-01-14 0:17 ` Andrew Morton
2015-01-13 23:37 ` Andrew Morton
2015-01-13 23:37 ` Andrew Morton
2015-01-14 8:06 ` Andrzej Hajda
2015-01-14 8:06 ` Andrzej Hajda
2015-01-14 14:12 ` Tejun Heo
2015-01-14 14:12 ` Tejun Heo
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