| Message ID | 20200629055530.3244342-5-songliubraving@fb.com |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | bpf: introduce bpf_get_task_stack() | expand |
On 6/28/20 10:55 PM, Song Liu wrote: > The new test is similar to other bpf_iter tests. It dumps all > /proc/<pid>/stack to a seq_file. Here is some example output: > > pid: 2873 num_entries: 3 > [<0>] worker_thread+0xc6/0x380 > [<0>] kthread+0x135/0x150 > [<0>] ret_from_fork+0x22/0x30 > > pid: 2874 num_entries: 9 > [<0>] __bpf_get_stack+0x15e/0x250 > [<0>] bpf_prog_22a400774977bb30_dump_task_stack+0x4a/0xb3c > [<0>] bpf_iter_run_prog+0x81/0x170 > [<0>] __task_seq_show+0x58/0x80 > [<0>] bpf_seq_read+0x1c3/0x3b0 > [<0>] vfs_read+0x9e/0x170 > [<0>] ksys_read+0xa7/0xe0 > [<0>] do_syscall_64+0x4c/0xa0 > [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Note: To print the output, it is necessary to modify the selftest. I do not know what this sentence means. It seems confusing and probably not needed. > > Signed-off-by: Song Liu <songliubraving@fb.com> Acked-by: Yonghong Song <yhs@fb.com> > --- > .../selftests/bpf/prog_tests/bpf_iter.c | 17 +++++++++ > .../selftests/bpf/progs/bpf_iter_task_stack.c | 37 +++++++++++++++++++ > 2 files changed, 54 insertions(+) > create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c > index 1e2e0fced6e81..fed42755416db 100644 > --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c > +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c > @@ -5,6 +5,7 @@ > #include "bpf_iter_netlink.skel.h" > #include "bpf_iter_bpf_map.skel.h" > #include "bpf_iter_task.skel.h" > +#include "bpf_iter_task_stack.skel.h" > #include "bpf_iter_task_file.skel.h" > #include "bpf_iter_tcp4.skel.h" > #include "bpf_iter_tcp6.skel.h" > @@ -110,6 +111,20 @@ static void test_task(void) > bpf_iter_task__destroy(skel); > } > > +static void test_task_stack(void) > +{ > + struct bpf_iter_task_stack *skel; > + > + skel = bpf_iter_task_stack__open_and_load(); > + if (CHECK(!skel, "bpf_iter_task_stack__open_and_load", > + "skeleton open_and_load failed\n")) > + return; > + > + do_dummy_read(skel->progs.dump_task_stack); > + > + bpf_iter_task_stack__destroy(skel); > +} > + > static void test_task_file(void) > { > struct bpf_iter_task_file *skel; > @@ -452,6 +467,8 @@ void test_bpf_iter(void) > test_bpf_map(); > if (test__start_subtest("task")) > test_task(); > + if (test__start_subtest("task_stack")) > + test_task_stack(); > if (test__start_subtest("task_file")) > test_task_file(); > if (test__start_subtest("tcp4")) > diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c > new file mode 100644 > index 0000000000000..e40d32a2ed93d > --- /dev/null > +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c > @@ -0,0 +1,37 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (c) 2020 Facebook */ > +#include "bpf_iter.h" > +#include <bpf/bpf_helpers.h> > +#include <bpf/bpf_tracing.h> > + > +char _license[] SEC("license") = "GPL"; > + > +#define MAX_STACK_TRACE_DEPTH 64 > +unsigned long entries[MAX_STACK_TRACE_DEPTH]; > +#define SIZE_OF_ULONG (sizeof(unsigned long)) > + > +SEC("iter/task") > +int dump_task_stack(struct bpf_iter__task *ctx) > +{ > + struct seq_file *seq = ctx->meta->seq; > + struct task_struct *task = ctx->task; > + long i, retlen; > + > + if (task == (void *)0) > + return 0; > + > + retlen = bpf_get_task_stack(task, entries, > + MAX_STACK_TRACE_DEPTH * SIZE_OF_ULONG, 0); > + if (retlen < 0) > + return 0; > + > + BPF_SEQ_PRINTF(seq, "pid: %8u num_entries: %8u\n", task->pid, > + retlen / SIZE_OF_ULONG); > + for (i = 0; i < MAX_STACK_TRACE_DEPTH; i++) { > + if (retlen > i * SIZE_OF_ULONG) > + BPF_SEQ_PRINTF(seq, "[<0>] %pB\n", (void *)entries[i]); > + } > + BPF_SEQ_PRINTF(seq, "\n"); > + > + return 0; > +} >
> On Jun 29, 2020, at 8:06 AM, Yonghong Song <yhs@fb.com> wrote: > > > > On 6/28/20 10:55 PM, Song Liu wrote: >> The new test is similar to other bpf_iter tests. It dumps all >> /proc/<pid>/stack to a seq_file. Here is some example output: >> pid: 2873 num_entries: 3 >> [<0>] worker_thread+0xc6/0x380 >> [<0>] kthread+0x135/0x150 >> [<0>] ret_from_fork+0x22/0x30 >> pid: 2874 num_entries: 9 >> [<0>] __bpf_get_stack+0x15e/0x250 >> [<0>] bpf_prog_22a400774977bb30_dump_task_stack+0x4a/0xb3c >> [<0>] bpf_iter_run_prog+0x81/0x170 >> [<0>] __task_seq_show+0x58/0x80 >> [<0>] bpf_seq_read+0x1c3/0x3b0 >> [<0>] vfs_read+0x9e/0x170 >> [<0>] ksys_read+0xa7/0xe0 >> [<0>] do_syscall_64+0x4c/0xa0 >> [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> Note: To print the output, it is necessary to modify the selftest. > > I do not know what this sentence means. It seems confusing > and probably not needed. It means current do_dummy_read() doesn't check/print the contents of the seq_file: /* not check contents, but ensure read() ends without error */ while ((len = read(iter_fd, buf, sizeof(buf))) > 0) ; > >> Signed-off-by: Song Liu <songliubraving@fb.com> > > Acked-by: Yonghong Song <yhs@fb.com> Thanks! [...]
On 6/29/20 9:56 AM, Song Liu wrote: > > >> On Jun 29, 2020, at 8:06 AM, Yonghong Song <yhs@fb.com> wrote: >> >> >> >> On 6/28/20 10:55 PM, Song Liu wrote: >>> The new test is similar to other bpf_iter tests. It dumps all >>> /proc/<pid>/stack to a seq_file. Here is some example output: >>> pid: 2873 num_entries: 3 >>> [<0>] worker_thread+0xc6/0x380 >>> [<0>] kthread+0x135/0x150 >>> [<0>] ret_from_fork+0x22/0x30 >>> pid: 2874 num_entries: 9 >>> [<0>] __bpf_get_stack+0x15e/0x250 >>> [<0>] bpf_prog_22a400774977bb30_dump_task_stack+0x4a/0xb3c >>> [<0>] bpf_iter_run_prog+0x81/0x170 >>> [<0>] __task_seq_show+0x58/0x80 >>> [<0>] bpf_seq_read+0x1c3/0x3b0 >>> [<0>] vfs_read+0x9e/0x170 >>> [<0>] ksys_read+0xa7/0xe0 >>> [<0>] do_syscall_64+0x4c/0xa0 >>> [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 >>> Note: To print the output, it is necessary to modify the selftest. >> >> I do not know what this sentence means. It seems confusing >> and probably not needed. > > It means current do_dummy_read() doesn't check/print the contents of the > seq_file: > > /* not check contents, but ensure read() ends without error */ > while ((len = read(iter_fd, buf, sizeof(buf))) > 0) > ; I see. Thanks. It could be great if the commit message is more explicit about what 'modify' is. >> >>> Signed-off-by: Song Liu <songliubraving@fb.com> >> >> Acked-by: Yonghong Song <yhs@fb.com> > > Thanks! > > [...] >
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c index 1e2e0fced6e81..fed42755416db 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c @@ -5,6 +5,7 @@ #include "bpf_iter_netlink.skel.h" #include "bpf_iter_bpf_map.skel.h" #include "bpf_iter_task.skel.h" +#include "bpf_iter_task_stack.skel.h" #include "bpf_iter_task_file.skel.h" #include "bpf_iter_tcp4.skel.h" #include "bpf_iter_tcp6.skel.h" @@ -110,6 +111,20 @@ static void test_task(void) bpf_iter_task__destroy(skel); } +static void test_task_stack(void) +{ + struct bpf_iter_task_stack *skel; + + skel = bpf_iter_task_stack__open_and_load(); + if (CHECK(!skel, "bpf_iter_task_stack__open_and_load", + "skeleton open_and_load failed\n")) + return; + + do_dummy_read(skel->progs.dump_task_stack); + + bpf_iter_task_stack__destroy(skel); +} + static void test_task_file(void) { struct bpf_iter_task_file *skel; @@ -452,6 +467,8 @@ void test_bpf_iter(void) test_bpf_map(); if (test__start_subtest("task")) test_task(); + if (test__start_subtest("task_stack")) + test_task_stack(); if (test__start_subtest("task_file")) test_task_file(); if (test__start_subtest("tcp4")) diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c new file mode 100644 index 0000000000000..e40d32a2ed93d --- /dev/null +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Facebook */ +#include "bpf_iter.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +#define MAX_STACK_TRACE_DEPTH 64 +unsigned long entries[MAX_STACK_TRACE_DEPTH]; +#define SIZE_OF_ULONG (sizeof(unsigned long)) + +SEC("iter/task") +int dump_task_stack(struct bpf_iter__task *ctx) +{ + struct seq_file *seq = ctx->meta->seq; + struct task_struct *task = ctx->task; + long i, retlen; + + if (task == (void *)0) + return 0; + + retlen = bpf_get_task_stack(task, entries, + MAX_STACK_TRACE_DEPTH * SIZE_OF_ULONG, 0); + if (retlen < 0) + return 0; + + BPF_SEQ_PRINTF(seq, "pid: %8u num_entries: %8u\n", task->pid, + retlen / SIZE_OF_ULONG); + for (i = 0; i < MAX_STACK_TRACE_DEPTH; i++) { + if (retlen > i * SIZE_OF_ULONG) + BPF_SEQ_PRINTF(seq, "[<0>] %pB\n", (void *)entries[i]); + } + BPF_SEQ_PRINTF(seq, "\n"); + + return 0; +}
The new test is similar to other bpf_iter tests. It dumps all /proc/<pid>/stack to a seq_file. Here is some example output: pid: 2873 num_entries: 3 [<0>] worker_thread+0xc6/0x380 [<0>] kthread+0x135/0x150 [<0>] ret_from_fork+0x22/0x30 pid: 2874 num_entries: 9 [<0>] __bpf_get_stack+0x15e/0x250 [<0>] bpf_prog_22a400774977bb30_dump_task_stack+0x4a/0xb3c [<0>] bpf_iter_run_prog+0x81/0x170 [<0>] __task_seq_show+0x58/0x80 [<0>] bpf_seq_read+0x1c3/0x3b0 [<0>] vfs_read+0x9e/0x170 [<0>] ksys_read+0xa7/0xe0 [<0>] do_syscall_64+0x4c/0xa0 [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Note: To print the output, it is necessary to modify the selftest. Signed-off-by: Song Liu <songliubraving@fb.com> --- .../selftests/bpf/prog_tests/bpf_iter.c | 17 +++++++++ .../selftests/bpf/progs/bpf_iter_task_stack.c | 37 +++++++++++++++++++ 2 files changed, 54 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c