* [PATCH v2 bpf-next] bpf: fix raw_tp test run in preempt kernel
@ 2020-09-30 0:20 Song Liu
2020-09-30 3:23 ` Alexei Starovoitov
0 siblings, 1 reply; 5+ messages in thread
From: Song Liu @ 2020-09-30 0:20 UTC (permalink / raw)
To: netdev, bpf; +Cc: kernel-team, ast, daniel, john.fastabend, kpsingh, Song Liu
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>
---
Changes v1 => v2:
1. Keep rcu_read_lock/unlock() in original places. (Alexei)
2. Use get_cpu() instead of smp_processor_id(). (Alexei)
---
net/bpf/test_run.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index fde5db93507c4..c1c30a9f76f34 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;
- }
-
+ } 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:
--
2.24.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2 bpf-next] bpf: fix raw_tp test run in preempt kernel
2020-09-30 0:20 [PATCH v2 bpf-next] bpf: fix raw_tp test run in preempt kernel Song Liu
@ 2020-09-30 3:23 ` Alexei Starovoitov
2020-09-30 6:45 ` Song Liu
0 siblings, 1 reply; 5+ messages in thread
From: Alexei Starovoitov @ 2020-09-30 3:23 UTC (permalink / raw)
To: Song Liu
Cc: Network Development, bpf, Kernel Team, Alexei Starovoitov,
Daniel Borkmann, John Fastabend, KP Singh
On Tue, Sep 29, 2020 at 5:20 PM Song Liu <songliubraving@fb.com> wrote:
>
> 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>
>
> ---
> Changes v1 => v2:
> 1. Keep rcu_read_lock/unlock() in original places. (Alexei)
> 2. Use get_cpu() instead of smp_processor_id(). (Alexei)
Applying: bpf: fix raw_tp test run in preempt kernel
Using index info to reconstruct a base tree...
error: patch failed: net/bpf/test_run.c:293
error: net/bpf/test_run.c: patch does not apply
error: Did you hand edit your patch?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 bpf-next] bpf: fix raw_tp test run in preempt kernel
2020-09-30 3:23 ` Alexei Starovoitov
@ 2020-09-30 6:45 ` Song Liu
2020-09-30 15:35 ` Alexei Starovoitov
0 siblings, 1 reply; 5+ messages in thread
From: Song Liu @ 2020-09-30 6:45 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: Network Development, bpf, Kernel Team, Alexei Starovoitov,
Daniel Borkmann, John Fastabend, KP Singh
> On Sep 29, 2020, at 8:23 PM, Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>
> On Tue, Sep 29, 2020 at 5:20 PM Song Liu <songliubraving@fb.com> wrote:
>>
>> 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>
>>
>> ---
>> Changes v1 => v2:
>> 1. Keep rcu_read_lock/unlock() in original places. (Alexei)
>> 2. Use get_cpu() instead of smp_processor_id(). (Alexei)
>
> Applying: bpf: fix raw_tp test run in preempt kernel
> Using index info to reconstruct a base tree...
> error: patch failed: net/bpf/test_run.c:293
> error: net/bpf/test_run.c: patch does not apply
> error: Did you hand edit your patch?
This is so weird. I cannot apply it myself. :(
[localhost] g co -b bpf-next-temp
Switched to a new branch 'bpf-next-temp'
[localhost] g format-patch -b HEAD~1 --subject-prefix "PATCH v3 bpf-next"
0001-bpf-fix-raw_tp-test-run-in-preempt-kernel.patch
[localhost] g reset --hard HEAD~1
HEAD is now at b0efc216f5779 libbpf: Compile in PIC mode only for shared library case
[localhost] g am 0001-bpf-fix-raw_tp-test-run-in-preempt-kernel.patch
Applying: bpf: fix raw_tp test run in preempt kernel
error: patch failed: net/bpf/test_run.c:293
error: net/bpf/test_run.c: patch does not apply
Patch failed at 0001 bpf: fix raw_tp test run in preempt kernel
hint: Use 'git am --show-current-patch' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Any hint on how to fix this? Alternatively, could you please pull the
change from
https://git.kernel.org/pub/scm/linux/kernel/git/song/linux.git raw_tp_preempt_fix
Thanks,
Song
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 bpf-next] bpf: fix raw_tp test run in preempt kernel
2020-09-30 6:45 ` Song Liu
@ 2020-09-30 15:35 ` Alexei Starovoitov
2020-09-30 15:48 ` Song Liu
0 siblings, 1 reply; 5+ messages in thread
From: Alexei Starovoitov @ 2020-09-30 15:35 UTC (permalink / raw)
To: Song Liu, Alexei Starovoitov
Cc: Network Development, bpf, Kernel Team, Alexei Starovoitov,
Daniel Borkmann, John Fastabend, KP Singh
On 9/29/20 11:45 PM, Song Liu wrote:
>
>
>> On Sep 29, 2020, at 8:23 PM, Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>>
>> On Tue, Sep 29, 2020 at 5:20 PM Song Liu <songliubraving@fb.com> wrote:
>>>
>>> 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>
>>>
>>> ---
>>> Changes v1 => v2:
>>> 1. Keep rcu_read_lock/unlock() in original places. (Alexei)
>>> 2. Use get_cpu() instead of smp_processor_id(). (Alexei)
>>
>> Applying: bpf: fix raw_tp test run in preempt kernel
>> Using index info to reconstruct a base tree...
>> error: patch failed: net/bpf/test_run.c:293
>> error: net/bpf/test_run.c: patch does not apply
>> error: Did you hand edit your patch?
>
> This is so weird. I cannot apply it myself. :(
>
> [localhost] g co -b bpf-next-temp
> Switched to a new branch 'bpf-next-temp'
>
> [localhost] g format-patch -b HEAD~1 --subject-prefix "PATCH v3 bpf-next"
> 0001-bpf-fix-raw_tp-test-run-in-preempt-kernel.patch
could you try without -b ?
> [localhost] g reset --hard HEAD~1
> HEAD is now at b0efc216f5779 libbpf: Compile in PIC mode only for shared library case
>
> [localhost] g am 0001-bpf-fix-raw_tp-test-run-in-preempt-kernel.patch
> Applying: bpf: fix raw_tp test run in preempt kernel
> error: patch failed: net/bpf/test_run.c:293
> error: net/bpf/test_run.c: patch does not apply
> Patch failed at 0001 bpf: fix raw_tp test run in preempt kernel
> hint: Use 'git am --show-current-patch' to see the failed patch
> When you have resolved this problem, run "git am --continue".
> If you prefer to skip this patch, run "git am --skip" instead.
> To restore the original branch and stop patching, run "git am --abort".
very odd indeed.
> Any hint on how to fix this? Alternatively, could you please pull the
> change from
>
> https://git.kernel.org/pub/scm/linux/kernel/git/song/linux.git raw_tp_preempt_fix
pulled. thanks
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 bpf-next] bpf: fix raw_tp test run in preempt kernel
2020-09-30 15:35 ` Alexei Starovoitov
@ 2020-09-30 15:48 ` Song Liu
0 siblings, 0 replies; 5+ messages in thread
From: Song Liu @ 2020-09-30 15:48 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: Alexei Starovoitov, Network Development, bpf, Kernel Team,
Alexei Starovoitov, Daniel Borkmann, John Fastabend, KP Singh
> On Sep 30, 2020, at 8:35 AM, Alexei Starovoitov <ast@fb.com> wrote:
>
> On 9/29/20 11:45 PM, Song Liu wrote:
>>> On Sep 29, 2020, at 8:23 PM, Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>>>
>>> On Tue, Sep 29, 2020 at 5:20 PM Song Liu <songliubraving@fb.com> wrote:
>>>>
>>>> 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>
>>>>
>>>> ---
>>>> Changes v1 => v2:
>>>> 1. Keep rcu_read_lock/unlock() in original places. (Alexei)
>>>> 2. Use get_cpu() instead of smp_processor_id(). (Alexei)
>>>
>>> Applying: bpf: fix raw_tp test run in preempt kernel
>>> Using index info to reconstruct a base tree...
>>> error: patch failed: net/bpf/test_run.c:293
>>> error: net/bpf/test_run.c: patch does not apply
>>> error: Did you hand edit your patch?
>> This is so weird. I cannot apply it myself. :(
>> [localhost] g co -b bpf-next-temp
>> Switched to a new branch 'bpf-next-temp'
>> [localhost] g format-patch -b HEAD~1 --subject-prefix "PATCH v3 bpf-next"
>> 0001-bpf-fix-raw_tp-test-run-in-preempt-kernel.patch
>
> could you try without -b ?
Yes! -b is the problem here.
I think the right way to format-patch is to use --ignore-space-at-eol
instead of -b.
Thanks,
Song
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-09-30 15:48 UTC | newest]
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2020-09-30 0:20 [PATCH v2 bpf-next] bpf: fix raw_tp test run in preempt kernel Song Liu
2020-09-30 3:23 ` Alexei Starovoitov
2020-09-30 6:45 ` Song Liu
2020-09-30 15:35 ` Alexei Starovoitov
2020-09-30 15:48 ` Song Liu
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