From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 472C3365A19; Tue, 12 May 2026 18:10:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778609445; cv=none; b=g9Jn9d1UjP1OAQSGP73VBgJdFJbmd524XWufVrXmcLI0xhuRzN7gAkGWnpHqdptg3b5TDX9prWYufdO/pRTbOIlmGs59zHAQD2kgL8/0bgQaGfldpqbxtug1IAmbNWm+zYwZUqYAZ7gpVkBLRJ9VTAyS031OZ40miUb95P1YlgQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778609445; c=relaxed/simple; bh=irruQICVob6U5EVWdLIBSaU6k9mJy6rvFNWbfgJwhz8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c+HXJSh/v31o55iCfULqdhltBGlEwu/AsxawEgtRDTL7EKdfGuRG6UAIhOyuQkyysuSmxxxjKHaFP42osJ1Ye41YfVpMkxHzNDJ8tuYGRez5E8+ckcuLq3jYBeQpAt/klZA+PTsANbA+gaaIoMr39HUW5T9SMpn4JKszIewnac0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=aMFJwZ3o; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="aMFJwZ3o" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D18AEC2BCB0; Tue, 12 May 2026 18:10:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778609445; bh=irruQICVob6U5EVWdLIBSaU6k9mJy6rvFNWbfgJwhz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aMFJwZ3oBnlJuALv4jUOLwxQV+/II6ltxFMlDTz675AbGdJ2JbXCXMFBg4V8QJels c/RlIpZ0+enYR3fJtMNpOH347ylCUY95xhGiUrf64akfAZfRHmwHkEDx/MQRDLNH0c NYNiRi67cjyDlaocjokCEZA/p3fw0wfYcOx8M9ng= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Masami Hiramatsu (Google)" Subject: [PATCH 7.0 161/307] tracing/fprobe: Remove fprobe from hash in failure path Date: Tue, 12 May 2026 19:39:16 +0200 Message-ID: <20260512173943.521380133@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260512173940.117428952@linuxfoundation.org> References: <20260512173940.117428952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Masami Hiramatsu (Google) commit 845947aca6814f5723ed65e556eb5ee09493f05b upstream. When register_fprobe_ips() fails, it tries to remove a list of fprobe_hash_node from fprobe_ip_table, but it missed to remove fprobe itself from fprobe_table. Moreover, when removing the fprobe_hash_node which is added to rhltable once, it must use kfree_rcu() after removing from rhltable. To fix these issues, this reuses unregister_fprobe() internal code to rollback the half-way registered fprobe. Link: https://lore.kernel.org/all/177669366417.132053.17874946321744910456.stgit@mhiramat.tok.corp.google.com/ Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/fprobe.c | 90 ++++++++++++++++++++++++++------------------------ 1 file changed, 47 insertions(+), 43 deletions(-) --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -79,20 +79,27 @@ static const struct rhashtable_params fp }; /* Node insertion and deletion requires the fprobe_mutex */ -static int insert_fprobe_node(struct fprobe_hlist_node *node) +static int insert_fprobe_node(struct fprobe_hlist_node *node, struct fprobe *fp) { + int ret; + lockdep_assert_held(&fprobe_mutex); - return rhltable_insert(&fprobe_ip_table, &node->hlist, fprobe_rht_params); + ret = rhltable_insert(&fprobe_ip_table, &node->hlist, fprobe_rht_params); + /* Set the fprobe pointer if insertion was successful. */ + if (!ret) + WRITE_ONCE(node->fp, fp); + return ret; } /* Return true if there are synonims */ static bool delete_fprobe_node(struct fprobe_hlist_node *node) { - lockdep_assert_held(&fprobe_mutex); bool ret; - /* Avoid double deleting */ + lockdep_assert_held(&fprobe_mutex); + + /* Avoid double deleting and non-inserted nodes */ if (READ_ONCE(node->fp) != NULL) { WRITE_ONCE(node->fp, NULL); rhltable_remove(&fprobe_ip_table, &node->hlist, @@ -755,7 +762,6 @@ static int fprobe_init(struct fprobe *fp fp->hlist_array = hlist_array; hlist_array->fp = fp; for (i = 0; i < num; i++) { - hlist_array->array[i].fp = fp; addr = ftrace_location(addrs[i]); if (!addr) { fprobe_fail_cleanup(fp); @@ -819,6 +825,8 @@ int register_fprobe(struct fprobe *fp, c } EXPORT_SYMBOL_GPL(register_fprobe); +static int unregister_fprobe_nolock(struct fprobe *fp); + /** * register_fprobe_ips() - Register fprobe to ftrace by address. * @fp: A fprobe data structure to be registered. @@ -845,28 +853,25 @@ int register_fprobe_ips(struct fprobe *f if (ret) return ret; - hlist_array = fp->hlist_array; if (fprobe_is_ftrace(fp)) ret = fprobe_ftrace_add_ips(addrs, num); else ret = fprobe_graph_add_ips(addrs, num); - - if (!ret) { - add_fprobe_hash(fp); - for (i = 0; i < hlist_array->size; i++) { - ret = insert_fprobe_node(&hlist_array->array[i]); - if (ret) - break; - } - /* fallback on insert error */ - if (ret) { - for (i--; i >= 0; i--) - delete_fprobe_node(&hlist_array->array[i]); - } + if (ret) { + fprobe_fail_cleanup(fp); + return ret; } - if (ret) - fprobe_fail_cleanup(fp); + hlist_array = fp->hlist_array; + ret = add_fprobe_hash(fp); + for (i = 0; i < hlist_array->size && !ret; i++) + ret = insert_fprobe_node(&hlist_array->array[i], fp); + + if (ret) { + unregister_fprobe_nolock(fp); + /* In error case, wait for clean up safely. */ + synchronize_rcu(); + } return ret; } @@ -910,27 +915,12 @@ bool fprobe_is_registered(struct fprobe return true; } -/** - * unregister_fprobe() - Unregister fprobe. - * @fp: A fprobe data structure to be unregistered. - * - * Unregister fprobe (and remove ftrace hooks from the function entries). - * - * Return 0 if @fp is unregistered successfully, -errno if not. - */ -int unregister_fprobe(struct fprobe *fp) +static int unregister_fprobe_nolock(struct fprobe *fp) { - struct fprobe_hlist *hlist_array; + struct fprobe_hlist *hlist_array = fp->hlist_array; unsigned long *addrs = NULL; - int ret = 0, i, count; + int i, count; - mutex_lock(&fprobe_mutex); - if (!fp || !fprobe_registered(fp)) { - ret = -EINVAL; - goto out; - } - - hlist_array = fp->hlist_array; addrs = kcalloc(hlist_array->size, sizeof(unsigned long), GFP_KERNEL); if (!addrs) { ret = -ENOMEM; /* TODO: Fallback to one-by-one loop */ @@ -952,12 +942,26 @@ int unregister_fprobe(struct fprobe *fp) kfree_rcu(hlist_array, rcu); fp->hlist_array = NULL; + kfree(addrs); -out: - mutex_unlock(&fprobe_mutex); + return 0; +} - kfree(addrs); - return ret; +/** + * unregister_fprobe() - Unregister fprobe. + * @fp: A fprobe data structure to be unregistered. + * + * Unregister fprobe (and remove ftrace hooks from the function entries). + * + * Return 0 if @fp is unregistered successfully, -errno if not. + */ +int unregister_fprobe(struct fprobe *fp) +{ + guard(mutex)(&fprobe_mutex); + if (!fp || !fprobe_registered(fp)) + return -EINVAL; + + return unregister_fprobe_nolock(fp); } EXPORT_SYMBOL_GPL(unregister_fprobe);