linux-kernel - Re: kmemleak for MIPS

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Message-ID: <AANLkTi=vcn5jHpk0O8XS9XJ8s5k-mCnzUwu70mFTx4=g@mail.gmail.com>
Date:	Wed, 30 Mar 2011 14:24:59 +0300
From:	Daniel Baluta <dbaluta@...acom.com>
To:	Maxin John <maxin.john@...il.com>
Cc:	naveen yadav <yad.naveen@...il.com>, linux-mips@...ux-mips.org,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Catalin Marinas <catalin.marinas@....com>,
	Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: kmemleak for MIPS

We have:

> UDP hash table entries: 128 (order: 0, 4096 bytes)
> CONFIG_BASE_SMALL=0

udp_table_init looks like:

        if (!CONFIG_BASE_SMALL)
                table->hash = alloc_large_system_hash(name, .. &table->mask);
        /*
         * Make sure hash table has the minimum size
         */

Since CONFIG_BASE_SMALL is 0, we are allocating the hash using
alloc_large_system
Then:
        if (CONFIG_BASE_SMALL || table->mask < UDP_HTABLE_SIZE_MIN - 1) {
                table->hash = kmalloc();

table->mask is 127, and UDP_HTABLE_SIZE_MIN is 256, so we are allocating again
table->hash without freeing already allocated memory.

We could free table->hash, before allocating the memory with kmalloc.
I don't fully understand the condition table->mask < UDP_HTABLE_SIZE_MIN - 1.

Eric?

thanks,
Daniel.
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