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bpf: fix raw_tp test run in preempt kernel
In preempt kernel, BPF_PROG_TEST_RUN on raw_tp triggers:
[ 35.874974] BUG: using smp_processor_id() in preemptible [00000000]
code: new_name/87
[ 35.893983] caller is bpf_prog_test_run_raw_tp+0xd4/0x1b0
[ 35.900124] CPU: 1 PID: 87 Comm: new_name Not tainted 5.9.0-rc6-g615bd02bf #1
[ 35.907358] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.10.2-1ubuntu1 04/01/2014
[ 35.916941] Call Trace:
[ 35.919660] dump_stack+0x77/0x9b
[ 35.923273] check_preemption_disabled+0xb4/0xc0
[ 35.928376] bpf_prog_test_run_raw_tp+0xd4/0x1b0
[ 35.933872] ? selinux_bpf+0xd/0x70
[ 35.937532] __do_sys_bpf+0x6bb/0x21e0
[ 35.941570] ? find_held_lock+0x2d/0x90
[ 35.945687] ? vfs_write+0x150/0x220
[ 35.949586] do_syscall_64+0x2d/0x40
[ 35.953443] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fix this by calling migrate_disable() before smp_processor_id().
Fixes: 1b4d60ec16
("bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
parent
b0efc216f5
commit
963ec27a10
@ -252,9 +252,7 @@ __bpf_prog_test_run_raw_tp(void *data)
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struct bpf_raw_tp_test_run_info *info = data;
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rcu_read_lock();
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migrate_disable();
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info->retval = BPF_PROG_RUN(info->prog, info->ctx);
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migrate_enable();
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rcu_read_unlock();
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}
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@ -266,6 +264,7 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
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__u32 ctx_size_in = kattr->test.ctx_size_in;
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struct bpf_raw_tp_test_run_info info;
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int cpu = kattr->test.cpu, err = 0;
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int current_cpu;
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/* doesn't support data_in/out, ctx_out, duration, or repeat */
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if (kattr->test.data_in || kattr->test.data_out ||
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@ -293,27 +292,25 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
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info.prog = prog;
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current_cpu = get_cpu();
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if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 ||
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cpu == smp_processor_id()) {
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cpu == current_cpu) {
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__bpf_prog_test_run_raw_tp(&info);
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} else {
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} else if (cpu >= nr_cpu_ids || !cpu_online(cpu)) {
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/* smp_call_function_single() also checks cpu_online()
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* after csd_lock(). However, since cpu is from user
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* space, let's do an extra quick check to filter out
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* invalid value before smp_call_function_single().
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*/
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if (cpu >= nr_cpu_ids || !cpu_online(cpu)) {
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err = -ENXIO;
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goto out;
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}
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err = -ENXIO;
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} else {
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err = smp_call_function_single(cpu, __bpf_prog_test_run_raw_tp,
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&info, 1);
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if (err)
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goto out;
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}
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put_cpu();
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if (copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
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if (!err &&
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copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
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err = -EFAULT;
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out:
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