Re: [PATCH net] ipv4: convert fib_num_tclassid_users to atomic_t

On Wed, Dec 1, 2021 at 6:42 PM David Ahern [off-list ref] wrote:

On 12/1/21 7:26 PM, Eric Dumazet wrote:

quoted

From: Eric Dumazet <redacted>

Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.

After the change, this is no longer the case, as free_fib_info_rcu()
runs after rcu grace period, without rtnl being held.

Fixes: faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
Signed-off-by: Eric Dumazet <redacted>
Cc: David Ahern <dsahern@kernel.org>
---
 include/net/ip_fib.h     | 2 +-
 include/net/netns/ipv4.h | 2 +-
 net/ipv4/fib_frontend.c  | 2 +-
 net/ipv4/fib_rules.c     | 4 ++--
 net/ipv4/fib_semantics.c | 4 ++--
 5 files changed, 7 insertions(+), 7 deletions(-)

Thanks, Eric. Was this found by syzbot or code inspection?

Code inspection, while plumbing my dev_hold_track() and dev_put_track() helpers.

Reviewed-by: David Ahern <dsahern@kernel.org>