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authorSong Liu <songliubraving@fb.com>2020-09-30 00:29:49 +0200
committerAlexei Starovoitov <ast@kernel.org>2020-09-30 17:34:08 +0200
commit963ec27a10fa6dc700c0465e95965c0bf696a606 (patch)
tree57886dddd58d323ba777bb82fd79ee3df5f85e27 /net/bpf
parentlibbpf: Compile in PIC mode only for shared library case (diff)
downloadlinux-963ec27a10fa6dc700c0465e95965c0bf696a606.tar.xz
linux-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')
-rw-r--r--net/bpf/test_run.c21
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: