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author | Alexei Starovoitov <ast@kernel.org> | 2020-07-01 08:22:09 -0700 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2020-07-01 08:26:22 -0700 |
commit | 64f0013c073a0162a6bd31b33def10cb2b2fe6e0 (patch) | |
tree | a29d6395f179a6937340702516a4a2d5bd066e0e /kernel/trace/bpf_trace.c | |
parent | bba1dc0b55ac462d24ed1228ad49800c238cd6d7 (diff) | |
parent | c7568114bc56cf3ec0bd9eb117bbe7cad3d30e11 (diff) | |
download | linux-stable-64f0013c073a0162a6bd31b33def10cb2b2fe6e0.tar.gz linux-stable-64f0013c073a0162a6bd31b33def10cb2b2fe6e0.tar.bz2 linux-stable-64f0013c073a0162a6bd31b33def10cb2b2fe6e0.zip |
Merge branch 'bpf_get_task_stack'
Song Liu says:
====================
This set introduces a new helper bpf_get_task_stack(). The primary use case
is to dump all /proc/*/stack to seq_file via bpf_iter__task.
A few different approaches have been explored and compared:
1. A simple wrapper around stack_trace_save_tsk(), as v1 [1].
This approach introduces new syntax, which is different to existing
helper bpf_get_stack(). Therefore, this is not ideal.
2. Extend get_perf_callchain() to support "task" as argument.
This approach reuses most of bpf_get_stack(). However, extending
get_perf_callchain() requires non-trivial changes to architecture
specific code. Which is error prone.
3. Current (v2) approach, leverages most of existing bpf_get_stack(), and
uses stack_trace_save_tsk() to handle architecture specific logic.
[1] https://lore.kernel.org/netdev/20200623070802.2310018-1-songliubraving@fb.com/
Changes v4 => v5:
1. Rebase and work around git-am issue. (Alexei)
2. Update commit log for 4/4. (Yonghong)
Changes v3 => v4:
1. Simplify the selftests with bpf_iter.h. (Yonghong)
2. Add example output to commit log of 4/4. (Yonghong)
Changes v2 => v3:
1. Rebase on top of bpf-next. (Yonghong)
2. Sanitize get_callchain_entry(). (Peter)
3. Use has_callchain_buf for bpf_get_task_stack. (Andrii)
4. Other small clean up. (Yonghong, Andrii).
Changes v1 => v2:
1. Reuse most of bpf_get_stack() logic. (Andrii)
2. Fix unsigned long vs. u64 mismatch for 32-bit systems. (Yonghong)
3. Add %pB support in bpf_trace_printk(). (Daniel)
4. Fix buffer size to bytes.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/trace/bpf_trace.c')
-rw-r--r-- | kernel/trace/bpf_trace.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 5d59dda5f661..1d874d8e4384 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -376,7 +376,7 @@ static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, /* * Only limited trace_printk() conversion specifiers allowed: - * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pks %pus %s + * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pB %pks %pus %s */ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, u64, arg2, u64, arg3) @@ -420,6 +420,11 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, goto fmt_str; } + if (fmt[i + 1] == 'B') { + i++; + goto fmt_next; + } + /* disallow any further format extensions */ if (fmt[i + 1] != 0 && !isspace(fmt[i + 1]) && @@ -636,7 +641,8 @@ BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, if (fmt[i] == 'p') { if (fmt[i + 1] == 0 || fmt[i + 1] == 'K' || - fmt[i + 1] == 'x') { + fmt[i + 1] == 'x' || + fmt[i + 1] == 'B') { /* just kernel pointers */ params[fmt_cnt] = args[fmt_cnt]; fmt_cnt++; @@ -1137,6 +1143,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_ringbuf_query_proto; case BPF_FUNC_jiffies64: return &bpf_jiffies64_proto; + case BPF_FUNC_get_task_stack: + return &bpf_get_task_stack_proto; default: return NULL; } |