Files
linux-cix/kernel
Alexei Starovoitov 63f13eb5d6 bpf: Avoid kfree_rcu() under lock in bpf_lpm_trie.
[ Upstream commit 59f2f841179aa6a0899cb9cf53659149a35749b7 ]

syzbot reported the following lock sequence:
cpu 2:
  grabs timer_base lock
    spins on bpf_lpm lock

cpu 1:
  grab rcu krcp lock
    spins on timer_base lock

cpu 0:
  grab bpf_lpm lock
    spins on rcu krcp lock

bpf_lpm lock can be the same.
timer_base lock can also be the same due to timer migration.
but rcu krcp lock is always per-cpu, so it cannot be the same lock.
Hence it's a false positive.
To avoid lockdep complaining move kfree_rcu() after spin_unlock.

Reported-by: syzbot+1fa663a2100308ab6eab@syzkaller.appspotmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240329171439.37813-1-alexei.starovoitov@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-19 06:04:27 +02:00
..
2024-06-27 13:49:13 +02:00
2023-11-28 17:19:40 +00:00
2024-06-12 11:12:52 +02:00
2023-09-19 13:21:33 -07:00
2024-06-12 11:12:52 +02:00