Files
linux/kernel
Dave Marchevsky 5861d1e8db bpf: Allow bpf_spin_{lock,unlock} in sleepable progs
Commit 9e7a4d9831 ("bpf: Allow LSM programs to use bpf spin locks")
disabled bpf_spin_lock usage in sleepable progs, stating:

 Sleepable LSM programs can be preempted which means that allowng spin
 locks will need more work (disabling preemption and the verifier
 ensuring that no sleepable helpers are called when a spin lock is
 held).

This patch disables preemption before grabbing bpf_spin_lock. The second
requirement above "no sleepable helpers are called when a spin lock is
held" is implicitly enforced by current verifier logic due to helper
calls in spin_lock CS being disabled except for a few exceptions, none
of which sleep.

Due to above preemption changes, bpf_spin_lock CS can also be considered
a RCU CS, so verifier's in_rcu_cs check is modified to account for this.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230821193311.3290257-7-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-25 09:23:17 -07:00
..
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