From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB075107A0; Thu, 4 Jul 2024 08:45:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720082737; cv=none; b=YjmuGu4H1Ka0NBX+ioQ8EfqBKCO7Yc/EcI1dJlHQtU5Woxc67u1h7Q1Ti4T86ko76X2SRbdDH9e8TdG/WLtrLWwSjD8wh8KHHopQt3l/HXpZHpAxk1OdagolhsXbKT5TNtxuATTfsOUg1rNhs0auc6L8lqwfvFq8/RYtBCEbwcA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720082737; c=relaxed/simple; bh=42P6ixEL1/t0fNcYlCm/UnkNeBXltpyRarpLhm/27Ow=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PUDu86utP7vewXhpDWSVdJmNeXwtDxq9hWOjgXa1nEdLjDn64fI4B8IXQnx3vYPrIuClg+FmqFiFh+F4ysgtTix9vCPYkaIi9CgvneEoVbygWGGNC9PQ/IfdnMRGVYSoG8Hm5+iweWxo7X8iWCVC536HwN610C+FiBQFH+C+mpk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=gE1uYFwn; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="gE1uYFwn" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=IApq68reoIapG8KugSynJUOaPB90tTvNFzIcvMXZOhA=; b=gE1uYFwnXyoI/NJJNvRZ15qHRM qP7WILc2ePpxx3GlfAfS3Lj9SOFnbI4LVY8+EYxxKQqtV7VIZj9yVbScKQn7A+zFje4ibIVH0nX6B 0xsH9o5cKMOzuzqBlfxQOtE2UjkpC+x0RfiPE3JwumDQ4cmpTho0cT2N88eoXib0IprevlI9tRDjd zGK3m+dnQht9XQDx/0iiJdR+v41+/oUYBzjrRS12eq06YjFUwQ5ku3bPy9oK6lV5r4dnZ3H5oJ48R Pg/XPQ8lXAcalRPwUx+DggZ+AZAW8zHsKBdLjIGPAo6m+TNcjYHfqzbERl8xUrCg8MIlNJyoiNLlQ RInI6XfA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1sPI5l-0000000ACcy-0RAA; Thu, 04 Jul 2024 08:45:27 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id B31713003FF; Thu, 4 Jul 2024 10:45:24 +0200 (CEST) Date: Thu, 4 Jul 2024 10:45:24 +0200 From: Peter Zijlstra To: Andrii Nakryiko Cc: Andrii Nakryiko , linux-trace-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, oleg@redhat.com, mingo@redhat.com, bpf@vger.kernel.org, jolsa@kernel.org, paulmck@kernel.org, clm@meta.com Subject: Re: [PATCH v2 04/12] uprobes: revamp uprobe refcounting and lifetime management Message-ID: <20240704084524.GC28838@noisy.programming.kicks-ass.net> References: <20240701223935.3783951-1-andrii@kernel.org> <20240701223935.3783951-5-andrii@kernel.org> <20240703133608.GO11386@noisy.programming.kicks-ass.net> <20240704080348.GP11386@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: bpf@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: <20240704080348.GP11386@noisy.programming.kicks-ass.net> On Thu, Jul 04, 2024 at 10:03:48AM +0200, Peter Zijlstra wrote: > diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c > index c98e3b3386ba..4aafb4485be7 100644 > --- a/kernel/trace/trace_uprobe.c > +++ b/kernel/trace/trace_uprobe.c > @@ -1112,7 +1112,8 @@ static void __probe_event_disable(struct trace_probe *tp) > if (!tu->inode) > continue; > > - uprobe_unregister(tu->inode, tu->offset, &tu->consumer); > + uprobe_unregister(tu->inode, tu->offset, &tu->consumer, > + list_is_last(trace_probe_probe_list(tp), &tu->tp.list) ? 0 : URF_NO_SYNC); > tu->inode = NULL; > } > } Hmm, that continue clause might ruin things. Still easy enough to add uprobe_unregister_sync() and simpy always pass URF_NO_SYNC. I really don't see why we should make this more complicated than it needs to be. diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 354cab634341..681741a51df3 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -115,7 +115,9 @@ extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern int uprobe_register_refctr(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc); extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool); -extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); +#define URF_NO_SYNC 0x01 +extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, unsigned int flags); +extern void uprobe_unregister_sync(void); extern int uprobe_mmap(struct vm_area_struct *vma); extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end); extern void uprobe_start_dup_mmap(void); @@ -165,7 +167,7 @@ uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, boo return -ENOSYS; } static inline void -uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) +uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, unsigned int flags) { } static inline int uprobe_mmap(struct vm_area_struct *vma) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 0b7574a54093..d09f7b942076 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1145,7 +1145,7 @@ __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc) * @offset: offset from the start of the file. * @uc: identify which probe if multiple probes are colocated. */ -void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) +void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, unsigned int flags) { scoped_guard (srcu, &uprobe_srcu) { struct uprobe *uprobe = find_uprobe(inode, offset); @@ -1157,10 +1157,17 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume mutex_unlock(&uprobe->register_mutex); } - synchronize_srcu(&uprobe_srcu); // XXX amortize / batch + if (!(flags & URF_NO_SYNC)) + synchronize_srcu(&uprobe_srcu); } EXPORT_SYMBOL_GPL(uprobe_unregister); +void uprobe_unregister_sync(void) +{ + synchronize_srcu(&uprobe_srcu); +} +EXPORT_SYMBOL_GPL(uprobe_unregister_sync); + /* * __uprobe_register - register a probe * @inode: the file in which the probe has to be placed. diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d1daeab1bbc1..1f6adabbb1e7 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3181,9 +3181,10 @@ static void bpf_uprobe_unregister(struct path *path, struct bpf_uprobe *uprobes, u32 i; for (i = 0; i < cnt; i++) { - uprobe_unregister(d_real_inode(path->dentry), uprobes[i].offset, - &uprobes[i].consumer); + uprobe_unregister(d_real_inode(path->dentry), uprobes[i].offset, URF_NO_SYNC); } + if (cnt > 0) + uprobe_unregister_sync(); } static void bpf_uprobe_multi_link_release(struct bpf_link *link) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index c98e3b3386ba..6b64470a1c5c 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -1104,6 +1104,7 @@ static int trace_uprobe_enable(struct trace_uprobe *tu, filter_func_t filter) static void __probe_event_disable(struct trace_probe *tp) { struct trace_uprobe *tu; + bool sync = false; tu = container_of(tp, struct trace_uprobe, tp); WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter)); @@ -1112,9 +1113,12 @@ static void __probe_event_disable(struct trace_probe *tp) if (!tu->inode) continue; - uprobe_unregister(tu->inode, tu->offset, &tu->consumer); + uprobe_unregister(tu->inode, tu->offset, &tu->consumer, URF_NO_SYNC); + sync = true; tu->inode = NULL; } + if (sync) + uprobe_unregister_sync(); } static int probe_event_enable(struct trace_event_call *call,