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Thu, 01 Aug 2024 10:06:50 -0400 X-MC-Unique: PwqJlKqZN-yuHHxW4zmYrA-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4EB7D1955D4B; Thu, 1 Aug 2024 14:06:46 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.225.183]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id DE9561955D48; Thu, 1 Aug 2024 14:06:40 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 1 Aug 2024 16:06:46 +0200 (CEST) Date: Thu, 1 Aug 2024 16:06:39 +0200 From: Oleg Nesterov To: Liao Chang Cc: mhiramat@kernel.org, peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH] uprobes: Improve scalability by reducing the contention on siglock Message-ID: <20240801140639.GE4038@redhat.com> References: <20240801082407.1618451-1-liaochang1@huawei.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240801082407.1618451-1-liaochang1@huawei.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 On 08/01, Liao Chang wrote: > > @@ -2276,22 +2277,25 @@ static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) > int err = 0; > > uprobe = utask->active_uprobe; > - if (utask->state == UTASK_SSTEP_ACK) > + switch (utask->state) { > + case UTASK_SSTEP_ACK: > err = arch_uprobe_post_xol(&uprobe->arch, regs); > - else if (utask->state == UTASK_SSTEP_TRAPPED) > + break; > + case UTASK_SSTEP_TRAPPED: > arch_uprobe_abort_xol(&uprobe->arch, regs); > - else > + fallthrough; > + case UTASK_SSTEP_DENY_SIGNAL: > + set_tsk_thread_flag(current, TIF_SIGPENDING); > + break; > + default: > WARN_ON_ONCE(1); > + } Liao, at first glance this change looks "obviously wrong" to me. But let me read this patch more carefully and reply on weekend, I am a bit busy right now. Thanks, Oleg.