On 9/29/20 11:45 PM, Song Liu wrote:
On Sep 29, 2020, at 8:23 PM, Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote:
On Tue, Sep 29, 2020 at 5:20 PM Song Liu <songliubraving@xxxxxx> 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@xxxxxxxxxx>
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
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
