diff options
| author | Ning Ding <dingning04@gmail.com> | 2026-08-05 16:39:33 -0700 |
|---|---|---|
| committer | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2026-08-06 15:46:43 +0200 |
| commit | d65739bf93be5160c1e0af00064874bbe262d5b6 (patch) | |
| tree | aba6421ef0054537a2d66515aefb898148cb4b30 /tools | |
| parent | 7d008cde75c07713cf5bb9371d187a0ad3a37a4c (diff) | |
| download | linux-next-d65739bf93be5160c1e0af00064874bbe262d5b6.tar.gz linux-next-d65739bf93be5160c1e0af00064874bbe262d5b6.zip | |
bpf: Account for preempt and IRQ state in RCU protection
Disabling preemption or local IRQs keeps the current CPU in an RCU
read-side critical section, but in_rcu_cs() does not account for either
state. The verifier therefore rejects safe kptr accesses and invalidates
pointers when another RCU source ends.
Include preemption-disabled and IRQ-disabled state in in_rcu_cs().
Invalidate RCU-protected pointers on RCU unlock, preempt enable, or IRQ
restore only after the final protection ends.
Signed-off-by: Ning Ding <dingning04@gmail.com>
Link: https://lore.kernel.org/bpf/20260805233940.3966981-2-dingning04@gmail.com
[ kkd: Simplify was_in_rcu_cs on spin unlock and adjust the selftest. ]
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/cpumask_failure.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/tools/testing/selftests/bpf/progs/cpumask_failure.c b/tools/testing/selftests/bpf/progs/cpumask_failure.c index 74b4cd4bcdbb..4628feb53d86 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_failure.c +++ b/tools/testing/selftests/bpf/progs/cpumask_failure.c @@ -116,9 +116,9 @@ int BPF_PROG(test_cpumask_null, struct task_struct *task, u64 clone_flags) return 0; } -SEC("tp_btf/task_newtask") +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") __failure __msg("R2 must be a rcu pointer") -int BPF_PROG(test_global_mask_out_of_rcu, struct task_struct *task, u64 clone_flags) +int BPF_PROG(test_global_mask_out_of_rcu) { struct bpf_cpumask *local, *prev; @@ -133,6 +133,10 @@ int BPF_PROG(test_global_mask_out_of_rcu, struct task_struct *task, u64 clone_fl return 0; } + /* + * Use a sleepable program so explicit RCU is the only source of RCU + * protection. + */ bpf_rcu_read_lock(); local = global_mask; if (!local) { |