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author | Masami Hiramatsu <mhiramat@kernel.org> | 2018-01-13 02:54:04 +0900 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2018-01-12 17:33:37 -0800 |
commit | b4da3340eae2c3932144be3e81ccfd4e424d87b7 (patch) | |
tree | 0a8d2bfcd4dc6a32524dc2b83d2c9169f9bf124a /kernel | |
parent | daaf24c634ab951cad3dcef28492001ef9c931d0 (diff) | |
download | linux-stable-b4da3340eae2c3932144be3e81ccfd4e424d87b7.tar.gz linux-stable-b4da3340eae2c3932144be3e81ccfd4e424d87b7.tar.bz2 linux-stable-b4da3340eae2c3932144be3e81ccfd4e424d87b7.zip |
tracing/kprobe: bpf: Check error injectable event is on function entry
Check whether error injectable event is on function entry or not.
Currently it checks the event is ftrace-based kprobes or not,
but that is wrong. It should check if the event is on the entry
of target function. Since error injection will override a function
to just return with modified return value, that operation must
be done before the target function starts making stackframe.
As a side effect, bpf error injection is no need to depend on
function-tracer. It can work with sw-breakpoint based kprobe
events too.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/Kconfig | 2 | ||||
-rw-r--r-- | kernel/trace/bpf_trace.c | 8 | ||||
-rw-r--r-- | kernel/trace/trace_kprobe.c | 9 | ||||
-rw-r--r-- | kernel/trace/trace_probe.h | 12 |
4 files changed, 16 insertions, 15 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index ae3a2d519e50..6400e1bf97c5 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -533,9 +533,7 @@ config FUNCTION_PROFILER config BPF_KPROBE_OVERRIDE bool "Enable BPF programs to override a kprobed function" depends on BPF_EVENTS - depends on KPROBES_ON_FTRACE depends on HAVE_KPROBE_OVERRIDE - depends on DYNAMIC_FTRACE_WITH_REGS default n help Allows BPF to override the execution of a probed function and diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f6d2327ecb59..1966ad3bf3e0 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -85,7 +85,7 @@ BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) { __this_cpu_write(bpf_kprobe_override, 1); regs_set_return_value(regs, rc); - arch_ftrace_kprobe_override_function(regs); + arch_kprobe_override_function(regs); return 0; } @@ -800,11 +800,11 @@ int perf_event_attach_bpf_prog(struct perf_event *event, int ret = -EEXIST; /* - * Kprobe override only works for ftrace based kprobes, and only if they - * are on the opt-in list. + * Kprobe override only works if they are on the function entry, + * and only if they are on the opt-in list. */ if (prog->kprobe_override && - (!trace_kprobe_ftrace(event->tp_event) || + (!trace_kprobe_on_func_entry(event->tp_event) || !trace_kprobe_error_injectable(event->tp_event))) return -EINVAL; diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 91f4b57dab82..3c8deb977a8b 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -88,13 +88,16 @@ static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) return nhit; } -int trace_kprobe_ftrace(struct trace_event_call *call) +bool trace_kprobe_on_func_entry(struct trace_event_call *call) { struct trace_kprobe *tk = (struct trace_kprobe *)call->data; - return kprobe_ftrace(&tk->rp.kp); + + return kprobe_on_func_entry(tk->rp.kp.addr, + tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, + tk->rp.kp.addr ? 0 : tk->rp.kp.offset); } -int trace_kprobe_error_injectable(struct trace_event_call *call) +bool trace_kprobe_error_injectable(struct trace_event_call *call) { struct trace_kprobe *tk = (struct trace_kprobe *)call->data; unsigned long addr; diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 5e54d748c84c..e101c5bb9eda 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -252,8 +252,8 @@ struct symbol_cache; unsigned long update_symbol_cache(struct symbol_cache *sc); void free_symbol_cache(struct symbol_cache *sc); struct symbol_cache *alloc_symbol_cache(const char *sym, long offset); -int trace_kprobe_ftrace(struct trace_event_call *call); -int trace_kprobe_error_injectable(struct trace_event_call *call); +bool trace_kprobe_on_func_entry(struct trace_event_call *call); +bool trace_kprobe_error_injectable(struct trace_event_call *call); #else /* uprobes do not support symbol fetch methods */ #define fetch_symbol_u8 NULL @@ -280,14 +280,14 @@ alloc_symbol_cache(const char *sym, long offset) return NULL; } -static inline int trace_kprobe_ftrace(struct trace_event_call *call) +static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call) { - return 0; + return false; } -static inline int trace_kprobe_error_injectable(struct trace_event_call *call) +static inline bool trace_kprobe_error_injectable(struct trace_event_call *call) { - return 0; + return false; } #endif /* CONFIG_KPROBE_EVENTS */ |