From f03efe49bd16c017107ff5079d08ea428e390dde Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 24 Feb 2020 15:01:35 +0100
Subject: bpf/tracing: Remove redundant preempt_disable() in __bpf_trace_run()
__bpf_trace_run() disables preemption around the BPF_PROG_RUN() invocation.
This is redundant because __bpf_trace_run() is invoked from a trace point
via __DO_TRACE() which already disables preemption _before_ invoking any of
the functions which are attached to a trace point.
Remove it and add a cant_sleep() check.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145642.847220186@linutronix.de
---
kernel/trace/bpf_trace.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
(limited to 'kernel/trace')
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index b8661bd0d028..4d42a5d05ec9 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1516,10 +1516,9 @@ void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
static __always_inline
void __bpf_trace_run(struct bpf_prog *prog, u64 *args)
{
+ cant_sleep();
rcu_read_lock();
- preempt_disable();
(void) BPF_PROG_RUN(prog, args);
- preempt_enable();
rcu_read_unlock();
}
--
cgit
From 1b7a51a63b031092b8b8acda3f6820b62a8b5e5d Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 24 Feb 2020 15:01:36 +0100
Subject: bpf/trace: Remove EXPORT from trace_call_bpf()
All callers are built in. No point to export this.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
kernel/trace/bpf_trace.c | 1 -
1 file changed, 1 deletion(-)
(limited to 'kernel/trace')
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 4d42a5d05ec9..15fafaed027c 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -119,7 +119,6 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
return ret;
}
-EXPORT_SYMBOL_GPL(trace_call_bpf);
#ifdef CONFIG_BPF_KPROBE_OVERRIDE
BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc)
--
cgit
From 70ed0706a48e3da3eb4515214fef658ff1184b9f Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@kernel.org>
Date: Mon, 24 Feb 2020 11:27:15 -0800
Subject: bpf: disable preemption for bpf progs attached to uprobe
trace_call_bpf() no longer disables preemption on its own.
All callers of this function has to do it explicitly.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/trace/trace_uprobe.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
(limited to 'kernel/trace')
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 18d16f3ef980..2a8e8e9c1c75 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1333,8 +1333,15 @@ static void __uprobe_perf_func(struct trace_uprobe *tu,
int size, esize;
int rctx;
- if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
- return;
+ if (bpf_prog_array_valid(call)) {
+ u32 ret;
+
+ preempt_disable();
+ ret = trace_call_bpf(call, regs);
+ preempt_enable();
+ if (!ret)
+ return;
+ }
esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
--
cgit
From b0a81b94cc50a112601721fcc2f91fab78d7b9f3 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 24 Feb 2020 15:01:37 +0100
Subject: bpf/trace: Remove redundant preempt_disable from trace_call_bpf()
Similar to __bpf_trace_run this is redundant because __bpf_trace_run() is
invoked from a trace point via __DO_TRACE() which already disables
preemption _before_ invoking any of the functions which are attached to a
trace point.
Remove it and add a cant_sleep() check.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145643.059995527@linutronix.de
---
kernel/trace/bpf_trace.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
(limited to 'kernel/trace')
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 15fafaed027c..07764c761073 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -83,7 +83,7 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
if (in_nmi()) /* not supported yet */
return 1;
- preempt_disable();
+ cant_sleep();
if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
/*
@@ -115,7 +115,6 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
out:
__this_cpu_dec(bpf_prog_active);
- preempt_enable();
return ret;
}
--
cgit