Re: [PATCH -stable,6.1 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)

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:  d6fc62cb7e09f 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
     
      ## include/net/netfilter/nf_tables.h ##
     @@ include/net/netfilter/nf_tables.h: struct nft_rule_blob {
    +  *	@use: number of jump references to this chain
    +  *	@flags: bitmask of enum nft_chain_flags
       *	@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 {
    + 	struct nft_rule_blob		__rcu *blob_gen_0;
     @@ include/net/netfilter/nf_tables.h: struct nft_chain {
      	char				*name;
      	u16				udlen;
---

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-6.6.y        |  Success    |  Success   |