Patch "netfilter: nft_set_pipapo_avx2: disable softinterrupts" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    netfilter: nft_set_pipapo_avx2: disable softinterrupts

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     netfilter-nft_set_pipapo_avx2-disable-softinterrupts.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b9c122a3a2a0b2611a60a22d4fbb830c9b588048
Author: Florian Westphal <fw@xxxxxxxxx>
Date:   Fri Jul 19 13:19:26 2024 +0200

    netfilter: nft_set_pipapo_avx2: disable softinterrupts
    
    [ Upstream commit a16909ae9982e931841c456061cb57fbaec9c59e ]
    
    We need to disable softinterrupts, else we get following problem:
    
    1. pipapo_avx2 called from process context; fpu usable
    2. preempt_disable() called, pcpu scratchmap in use
    3. softirq handles rx or tx, we re-enter pipapo_avx2
    4. fpu busy, fallback to generic non-avx version
    5. fallback reuses scratch map and index, which are in use
       by the preempted process
    
    Handle this same way as generic version by first disabling
    softinterrupts while the scratchmap is in use.
    
    Fixes: f0b3d338064e ("netfilter: nft_set_pipapo_avx2: Add irq_fpu_usable() check, fallback to non-AVX2 version")
    Cc: Stefano Brivio <sbrivio@xxxxxxxxxx>
    Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
    Reviewed-by: Stefano Brivio <sbrivio@xxxxxxxxxx>
    Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/netfilter/nft_set_pipapo_avx2.c b/net/netfilter/nft_set_pipapo_avx2.c
index 8910a5ac7ed12..b8d3c3213efee 100644
--- a/net/netfilter/nft_set_pipapo_avx2.c
+++ b/net/netfilter/nft_set_pipapo_avx2.c
@@ -1139,8 +1139,14 @@ bool nft_pipapo_avx2_lookup(const struct net *net, const struct nft_set *set,
 	bool map_index;
 	int i, ret = 0;
 
-	if (unlikely(!irq_fpu_usable()))
-		return nft_pipapo_lookup(net, set, key, ext);
+	local_bh_disable();
+
+	if (unlikely(!irq_fpu_usable())) {
+		bool fallback_res = nft_pipapo_lookup(net, set, key, ext);
+
+		local_bh_enable();
+		return fallback_res;
+	}
 
 	m = rcu_dereference(priv->match);
 
@@ -1155,6 +1161,7 @@ bool nft_pipapo_avx2_lookup(const struct net *net, const struct nft_set *set,
 	scratch = *raw_cpu_ptr(m->scratch);
 	if (unlikely(!scratch)) {
 		kernel_fpu_end();
+		local_bh_enable();
 		return false;
 	}
 
@@ -1235,6 +1242,7 @@ bool nft_pipapo_avx2_lookup(const struct net *net, const struct nft_set *set,
 	if (i % 2)
 		scratch->map_index = !map_index;
 	kernel_fpu_end();
+	local_bh_enable();
 
 	return ret >= 0;
 }