From: Florian Westphal <fw@strlen.de>
To: Stefano Brivio <sbrivio@redhat.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>,
kernel test robot <lkp@intel.com>,
Florian Westphal <fw@strlen.de>,
stable@vger.kernel.org, netfilter-devel@vger.kernel.org
Subject: Re: [PATCH nf] nft_set_pipapo: Disable preemption before getting per-CPU pointer
Date: Mon, 8 Jun 2020 10:56:52 +0200 [thread overview]
Message-ID: <20200608085652.GP28263@breakpoint.cc> (raw)
In-Reply-To: <45861d795de2db1494b40bb2cc13bb36b4dacf72.1591606165.git.sbrivio@redhat.com>
Stefano Brivio <sbrivio@redhat.com> wrote:
> The lkp kernel test robot reports, with CONFIG_DEBUG_PREEMPT enabled:
[..]
> diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
> index 8b5acc6910fd..8c04388296b0 100644
> --- a/net/netfilter/nft_set_pipapo.c
> +++ b/net/netfilter/nft_set_pipapo.c
> @@ -1242,7 +1242,9 @@ static int nft_pipapo_insert(const struct net *net, const struct nft_set *set,
> end += NFT_PIPAPO_GROUPS_PADDED_SIZE(f);
> }
>
> - if (!*this_cpu_ptr(m->scratch) || bsize_max > m->bsize_max) {
> + if (!*get_cpu_ptr(m->scratch) || bsize_max > m->bsize_max) {
> + put_cpu_ptr(m->scratch);
> +
> err = pipapo_realloc_scratch(m, bsize_max);
> if (err)
> return err;
> @@ -1250,6 +1252,8 @@ static int nft_pipapo_insert(const struct net *net, const struct nft_set *set,
> this_cpu_write(nft_pipapo_scratch_index, false);
Won't that mean that this_cpu_write() can occur on a different CPU than
the get_cpu_ptr() ptr check was done on?
next prev parent reply other threads:[~2020-06-08 8:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-08 8:50 [PATCH nf] nft_set_pipapo: Disable preemption before getting per-CPU pointer Stefano Brivio
2020-06-08 8:56 ` Florian Westphal [this message]
2020-06-08 9:05 ` Stefano Brivio
2020-06-09 21:48 ` Pablo Neira Ayuso
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