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| author | Song Liu <songliubraving@fb.com> | 2020-09-29 15:29:49 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-09-30 08:34:08 -0700 |
| commit | 963ec27a10fa6dc700c0465e95965c0bf696a606 (patch) | |
| tree | 57886dddd58d323ba777bb82fd79ee3df5f85e27 /net/bpf/test_run.c | |
| parent | b0efc216f577997bf563d76d51673ed79c3d5f71 (diff) | |
| download | lwn-963ec27a10fa6dc700c0465e95965c0bf696a606.tar.gz lwn-963ec27a10fa6dc700c0465e95965c0bf696a606.zip | |
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: 1b4d60ec162f ("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>
Diffstat (limited to 'net/bpf/test_run.c')
| -rw-r--r-- | net/bpf/test_run.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index fde5db93507c..c1c30a9f76f3 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -252,9 +252,7 @@ __bpf_prog_test_run_raw_tp(void *data) struct bpf_raw_tp_test_run_info *info = data; rcu_read_lock(); - migrate_disable(); info->retval = BPF_PROG_RUN(info->prog, info->ctx); - migrate_enable(); rcu_read_unlock(); } @@ -266,6 +264,7 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog, __u32 ctx_size_in = kattr->test.ctx_size_in; struct bpf_raw_tp_test_run_info info; int cpu = kattr->test.cpu, err = 0; + int current_cpu; /* doesn't support data_in/out, ctx_out, duration, or repeat */ if (kattr->test.data_in || kattr->test.data_out || @@ -293,27 +292,25 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog, info.prog = prog; + current_cpu = get_cpu(); if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 || - cpu == smp_processor_id()) { + cpu == current_cpu) { __bpf_prog_test_run_raw_tp(&info); - } else { + } else if (cpu >= nr_cpu_ids || !cpu_online(cpu)) { /* smp_call_function_single() also checks cpu_online() * after csd_lock(). However, since cpu is from user * space, let's do an extra quick check to filter out * invalid value before smp_call_function_single(). */ - if (cpu >= nr_cpu_ids || !cpu_online(cpu)) { - err = -ENXIO; - goto out; - } - + err = -ENXIO; + } else { err = smp_call_function_single(cpu, __bpf_prog_test_run_raw_tp, &info, 1); - if (err) - goto out; } + put_cpu(); - if (copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32))) + if (!err && + copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32))) err = -EFAULT; out: |