Re: [PATCH -stable,5.15 2/3] netfilter: nf_tables: wait for rcu grace period on net_device removal

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
ℹ️ This is part 2/3 of a series
⚠️ Found follow-up fixes in mainline

The upstream commit SHA1 provided is correct: c03d278fdf35e73dd0ec543b9b556876b9d9a8dc

Status in newer kernel trees:
6.14.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (different SHA1: bfd05c68e4c6)
6.1.y | Not found

Found fixes commits:
b04df3da1b5c netfilter: nf_tables: do not defer rule destruction via call_rcu

Note: The patch differs from the upstream commit:
---
1:  c03d278fdf35e ! 1:  14e8d506ade73 netfilter: nf_tables: wait for rcu grace period on net_device removal
    @@ Metadata
      ## Commit message ##
         netfilter: nf_tables: wait for rcu grace period on net_device removal
     
    +    commit c03d278fdf35e73dd0ec543b9b556876b9d9a8dc upstream.
    +
         8c873e219970 ("netfilter: core: free hooks with call_rcu") removed
         synchronize_net() call when unregistering basechain hook, however,
         net_device removal event handler for the NFPROTO_NETDEV was not updated
    @@ Commit message
         Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
     
      ## include/net/netfilter/nf_tables.h ##
    -@@ include/net/netfilter/nf_tables.h: struct nft_rule_blob {
    -  *	@name: name of the chain
    -  *	@udlen: user data length
    -  *	@udata: user data in the chain
    -+ *	@rcu_head: rcu head for deferred release
    -  *	@blob_next: rule blob pointer to the next in the chain
    -  */
    - struct nft_chain {
     @@ include/net/netfilter/nf_tables.h: struct nft_chain {
      	char				*name;
      	u16				udlen;
    @@ include/net/netfilter/nf_tables.h: struct nft_chain {
     +	struct rcu_head			rcu_head;
      
      	/* Only used during control plane commit phase: */
    - 	struct nft_rule_blob		*blob_next;
    + 	struct nft_rule			**rules_next;
     @@ include/net/netfilter/nf_tables.h: static inline void nft_use_inc_restore(u32 *use)
       *	@sets: sets in the table
       *	@objects: stateful objects in the table
---

NOTE: These results are for this patch alone. Full series testing will be
performed when all parts are received.

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |