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 B8FF955C33E for ; Tue, 8 Sep 2026 13:37:18 +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=1788874651; cv=none; b=KJOmjlTYiAzEoB1IrKgIGTuYYWLQZAGqyRNNp0wa0gMIU1WYL2cMREyvxb3TtmWxcUXw/Amnb7lH+O27oQsepIDvBfzibYvgwm+jtw7oaIqFEAEe9IicxPkOFmTpb5bEIZwjFdcqIFlobNffG/lAHKjXSvr7jzAEkWr3qJ997QU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788874651; c=relaxed/simple; bh=Uz48aSjYuL0qoRQNcVJXbDtoFGJ8aS6P/iFpIYsLoHI=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=bAEAjxdgsWVLK1KyL4GH2zwGo4JkmFNqrPvDkTLuSCNN1QrxiAvVuELgBtELlCUAwVCRsutcGWK4poeECg9QJ69ctxLEgydcrohrBCHuX/i0BSSvW5QTeGX024sIqvhvUvsjVgH3Kb1siwKQE+lqf7oTZ2TWA+UHWf0mpRestzE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=euQuW4dr; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="euQuW4dr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B7DE1F00A3E; Tue, 8 Sep 2026 13:37:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788874637; bh=TObTgOH3f/TRAc3thnDiiDD4vqKTjbPQL87bG+G1+iI=; h=Subject:To:Cc:From:Date; b=euQuW4drLgncWlcFGOHGh+Y9Sc6Y1g7og6b3n1XZNlt8J4MLpl6hjmsjs6vk+QSgo 54PX+P2iukKy+PWnqNlHW52VsLf21mNYjBvZnj+IvNjdrUF7PFd7RF62z01m1AiNo7 af2w9vCDBJN42Z9Pjf10kZvz3ZsNczTmr/ww4nH4= Subject: FAILED: patch "[PATCH] kprobes: Protect kprobe_blacklist with RCU" failed to apply to 5.15-stable tree To: mhiramat@kernel.org,sashiko-bot@kernel.org Cc: From: Date: Tue, 08 Sep 2026 15:32:33 +0200 Message-ID: <2026090833-aptitude-antibody-c550@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 0c4256196b3a105307e2235fbfd85e768bbcdd0f # git commit -s git send-email --to '' --in-reply-to '2026090833-aptitude-antibody-c550@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 0c4256196b3a105307e2235fbfd85e768bbcdd0f Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Sun, 30 Aug 2026 23:27:23 +0900 Subject: [PATCH] kprobes: Protect kprobe_blacklist with RCU __within_kprobe_blacklist() traverses kprobe_blacklist without holding kprobe_mutex. When a module is unloaded, kprobe_remove_area_blacklist() removes blacklist entries and immediately frees them with kfree(). A concurrent call to within_kprobe_blacklist() can therefore dereference freed memory. Furthermore, within_kprobe_blacklist() can be called in atomic or non-preemptible contexts where the sleeping kprobe_mutex cannot be taken. Protect kprobe_blacklist with RCU. Use guard(rcu)() and list_for_each_entry_rcu() for traversal, list_add_tail_rcu() for insertions, list_del_rcu() for deletions, and kfree_rcu() to reclaim entries safely after a grace period. Link: https://lore.kernel.org/all/178810004323.64882.16493230858653316962.stgit@devnote2/ Fixes: 376e242429bf ("kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist") Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260807155802.F06041F000E9@smtp.kernel.org/ Assisted-by: Antigravity:gemini-3.7-flash Signed-off-by: Masami Hiramatsu (Google) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 8c4f3bb24429..e6de7ae55bda 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -181,6 +181,7 @@ struct kprobe_blacklist_entry { struct list_head list; unsigned long start_addr; unsigned long end_addr; + struct rcu_head rcu; }; #ifdef CONFIG_KPROBES diff --git a/kernel/kprobes.c b/kernel/kprobes.c index bfc89083daa9..6337da5cab9e 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1447,8 +1447,14 @@ static bool __within_kprobe_blacklist(unsigned long addr) /* * If 'kprobe_blacklist' is defined, check the address and * reject any probe registration in the prohibited area. + * Note: this can return true during transition period where + * (start_addr, end_addr) in the black list is shrinking + * but old entry has not been removed yet. This is acceptable + * because the worst case is that we reject more probes than + * we should. */ - list_for_each_entry(ent, &kprobe_blacklist, list) { + guard(rcu)(); + list_for_each_entry_rcu(ent, &kprobe_blacklist, list) { if (addr >= ent->start_addr && addr < ent->end_addr) return true; } @@ -2509,7 +2515,7 @@ int kprobe_add_ksym_blacklist(unsigned long entry) ent->start_addr = entry; ent->end_addr = entry + size; INIT_LIST_HEAD(&ent->list); - list_add_tail(&ent->list, &kprobe_blacklist); + list_add_tail_rcu(&ent->list, &kprobe_blacklist); return (int)size; } @@ -2603,8 +2609,8 @@ static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { if (ent->start_addr < start || ent->start_addr >= end) continue; - list_del(&ent->list); - kfree(ent); + list_del_rcu(&ent->list); + kfree_rcu(ent, rcu); } }