linux-kernel - [PATCH v3 44/57] perf: Simplify bpf_overflow

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230612093540.708955479@infradead.org>
Date:   Mon, 12 Jun 2023 11:07:57 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     torvalds@...ux-foundation.org, keescook@...omium.org,
        gregkh@...uxfoundation.org, pbonzini@...hat.com
Cc:     masahiroy@...nel.org, nathan@...nel.org, ndesaulniers@...gle.com,
        nicolas@...sle.eu, catalin.marinas@....com, will@...nel.org,
        vkoul@...nel.org, trix@...hat.com, ojeda@...nel.org,
        peterz@...radead.org, mingo@...hat.com, longman@...hat.com,
        boqun.feng@...il.com, dennis@...nel.org, tj@...nel.org,
        cl@...ux.com, acme@...nel.org, mark.rutland@....com,
        alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
        namhyung@...nel.org, irogers@...gle.com, adrian.hunter@...el.com,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de, bristot@...hat.com, vschneid@...hat.com,
        paulmck@...nel.org, frederic@...nel.org, quic_neeraju@...cinc.com,
        joel@...lfernandes.org, josh@...htriplett.org,
        mathieu.desnoyers@...icios.com, jiangshanlai@...il.com,
        rientjes@...gle.com, vbabka@...e.cz, roman.gushchin@...ux.dev,
        42.hyeyoo@...il.com, apw@...onical.com, joe@...ches.com,
        dwaipayanray1@...il.com, lukas.bulwahn@...il.com,
        john.johansen@...onical.com, paul@...l-moore.com,
        jmorris@...ei.org, serge@...lyn.com, linux-kbuild@...r.kernel.org,
        linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org,
        llvm@...ts.linux.dev, linux-perf-users@...r.kernel.org,
        rcu@...r.kernel.org, linux-security-module@...r.kernel.org,
        tglx@...utronix.de, ravi.bangoria@....com, error27@...il.com,
        luc.vanoostenryck@...il.com
Subject: [PATCH v3 44/57] perf: Simplify bpf_overflow_handler()


Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/events/core.c |   16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10288,16 +10288,14 @@ static void bpf_overflow_handler(struct
 	int ret = 0;
 
 	ctx.regs = perf_arch_bpf_user_pt_regs(regs);
-	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
-		goto out;
-	rcu_read_lock();
-	prog = READ_ONCE(event->prog);
-	if (prog) {
-		perf_prepare_sample(data, event, regs);
-		ret = bpf_prog_run(prog, &ctx);
+	if (likely(__this_cpu_inc_return(bpf_prog_active) == 1)) {
+		guard(rcu)();
+		prog = READ_ONCE(event->prog);
+		if (prog) {
+			perf_prepare_sample(data, event, regs);
+			ret = bpf_prog_run(prog, &ctx);
+		}
 	}
-	rcu_read_unlock();
-out:
 	__this_cpu_dec(bpf_prog_active);
 	if (!ret)
 		return;