From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7785425F99F for ; Sat, 3 Oct 2026 00:24:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790987075; cv=none; b=G9boPbptnnyI9MofZyK5UoE7mJ+1XJoVqCTnAr2/xcfcxE1SRMS/SEx6Rs4HpNFYrGsEDx4BWyLOq7Yiv14BxeveH/Vqwezt9u5GFah5dOOtVoQGBswn+yzWV/+/+aP9nh9OM8uOZmgoQuXyOcIreDUi/txQsyGofMTW4KYgQ20= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790987075; c=relaxed/simple; bh=LHNt0q8ITEJWpeoIOMFW4aGpkmBnNFsIk7DmHwVsRcw=; h=Date:From:To:Cc:Subject:Message-Id:Mime-Version:Content-Type; b=HJ4VDAm3AXzmreXiFWx8y/fTmGusryldFMPJOCvXOTFwriNXn3HX89F5utmRxNgN8zB4XzxawwrC8ZhIEeUYHj6eJ+FkYnKOQ6pfxf2jC9Lfvf23xJHHWffVgnT+JphDJ3t2eus5JpI76ukS3IPLwbyPJmPX/Yc+8c2HmQE4f8o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=INDdHu0o; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="INDdHu0o" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C2B41F000FF; Sat, 3 Oct 2026 00:24:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790987072; bh=aKa+6vV6kkTqtq9G2KZj/NeNI4iyajbFnzjmlwkUFPQ=; h=Date:From:To:Cc:Subject; b=INDdHu0op5saSf6BpebXK/5RQpbmmWu1S9sAri7PiGmmCQ7oLajhiqBBre6m4lx6L w9VuH7ffB8p633s4wgGtgApOC9UN80A8RocsfQXiGtOt2J7YzB1327SbpX4ML1Uebc BHs2esF+oyBKD6VYwH4JuGt+Cwy0dgJBNjc1tM6rP0uro0EqTvSJ/yAvjHBanc+Leh AhblQAJycB960PnV4bAdUbP/4zwygaLe1V82AdqTBbGNBiXbyZC325lCik2kw0OZ1e rtD5lW3DLE+52mCHZiDRnDK1bd3302KMpy3d75RWfsSMU03wWTw0tuu9DIII4168id ECokhRULSR8VQ== Date: Sat, 3 Oct 2026 09:24:28 +0900 From: Masami Hiramatsu (Google) To: Linus Torvalds Cc: Leon Hwang , Masami Hiramatsu (Google) , Steven Rostedt , Masami Hiramatsu , linux-kernel@vger.kernel.org Subject: [GIT PULL] probes: Fixes for v7.3-rc5 Message-Id: <20261003092428.77fca44f8fa79bf95a1711c1@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Hi Linus, Probes fixes for v7.3-rc5: - fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching(): Exit handlers early if !rcu_is_watching() to prevent potential use-after-free during unregistration in idle/quiescent states. Switch to guard(rcu_sched_notrace) to avoid fast-path lockdep overhead and recursion while ensuring safe grace period synchronization. - kprobes: Skip disarmed probes when checking optkprobe overlap: Continue past disarmed or unprepared probes in get_optimized_kprobe() to find active optimized probes. This avoids overwriting active jump displacements which can lead to panic. Please pull the latest probes-fixes-v7.3-rc5 tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git probes-fixes-v7.3-rc5 Tag SHA1: 6306ca9d4f07bccf04980b6a4031476e36037f3b Head SHA1: 7a39c732a22ec4a369af9e19fbe3d666ec83eec4 Leon Hwang (1): kprobes: Skip disarmed probes when checking optkprobe overlap Masami Hiramatsu (Google) (1): fprobe: Use guard(rcu_sched_notrace) and check rcu_is_watching() ---- kernel/kprobes.c | 8 +++++--- kernel/trace/fprobe.c | 26 ++++++++++++++++---------- 2 files changed, 21 insertions(+), 13 deletions(-) --------------------------- diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 4edd8ca5c657..e787e4948c8b 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -496,14 +496,16 @@ static bool kprobe_queued(struct kprobe *p) static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr) { int i; - struct kprobe *p = NULL; + struct kprobe *p; struct optimized_kprobe *op; /* Don't check i == 0, since that is a breakpoint case. */ - for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++) + for (i = 1; i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++) { p = get_kprobe(addr - i); + /* A disabled probe can have prepared, but inactive, optinsns. */ + if (!p || !kprobe_optready(p) || kprobe_disarmed(p)) + continue; - if (p && kprobe_optready(p)) { op = container_of(p, struct optimized_kprobe, kp); if (arch_within_optimized_kprobe(op, addr)) return p; diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 9f2d98181779..da286619c5d8 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -47,6 +47,10 @@ static struct rhltable fprobe_ip_table; static DEFINE_MUTEX(fprobe_mutex); static struct fgraph_ops fprobe_graph_ops; +DEFINE_LOCK_GUARD_0(rcu_sched_notrace, + rcu_read_lock_sched_notrace(), + rcu_read_unlock_sched_notrace()) + static u32 fprobe_node_hashfn(const void *data, u32 len, u32 seed) { return hash_ptr(*(unsigned long **)data, 32); @@ -329,16 +333,14 @@ static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip, struct fprobe *fp; int bit; + if (!rcu_is_watching()) + return; + bit = ftrace_test_recursion_trylock(ip, parent_ip); if (bit < 0) return; - /* - * ftrace_test_recursion_trylock() disables preemption, but - * rhltable_lookup() checks whether rcu_read_lcok is held. - * So we take rcu_read_lock() here. - */ - rcu_read_lock(); + guard(rcu_sched_notrace)(); head = rhltable_lookup(&fprobe_ip_table, &ip, fprobe_rht_params); rhl_for_each_entry_rcu(node, pos, head, hlist) { @@ -353,7 +355,6 @@ static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip, else __fprobe_handler(ip, parent_ip, fp, fregs, NULL); } - rcu_read_unlock(); ftrace_test_recursion_unlock(bit); } NOKPROBE_SYMBOL(fprobe_ftrace_entry); @@ -567,10 +568,13 @@ static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops struct fprobe *fp; int used, ret; + if (!rcu_is_watching()) + return 0; + if (WARN_ON_ONCE(!fregs)) return 0; - guard(rcu)(); + guard(rcu_sched_notrace)(); head = rhltable_lookup(&fprobe_ip_table, &func, fprobe_rht_params); reserved_words = 0; rhl_for_each_entry_rcu(node, pos, head, hlist) { @@ -665,13 +669,16 @@ static void fprobe_return(struct ftrace_graph_ret *trace, int size, curr; int size_words; + if (!rcu_is_watching()) + return; + fgraph_data = (unsigned long *)fgraph_retrieve_data(gops->idx, &size); if (WARN_ON_ONCE(!fgraph_data)) return; size_words = SIZE_IN_LONG(size); ret_ip = ftrace_regs_get_instruction_pointer(fregs); - preempt_disable_notrace(); + guard(rcu_sched_notrace)(); curr = 0; while (size_words > curr) { @@ -687,7 +694,6 @@ static void fprobe_return(struct ftrace_graph_ret *trace, } curr += size; } - preempt_enable_notrace(); } NOKPROBE_SYMBOL(fprobe_return); -- Masami Hiramatsu (Google)