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 83D1B372B39 for ; Mon, 31 Aug 2026 16:43:17 +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=1788194598; cv=none; b=BYgJb7YN82GqFfJdRCzmEAa7njxUHaQ6pFQTKNiNERICoJFope4vFSAwIrBa7NwNg2vOBnsc6APk5rHeBc0n64MS7GJABOwXZlnLQPGpJx+5rKqvYj7SGHRXqemQStCzDwBlpAg1y90ZmLjOdKUHAcj8wHHJ7usHbXypGbMLiG8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788194598; c=relaxed/simple; bh=yGI65JIB8GJgRprwvlTdcQ7TYnzfTNyBVEQ0tE9O+uA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jAdK+N1AgUFsrcd07occ1FVsjoeoBYgLNAkuK6eiEfXPgBV8PYvfDX6lsRO9AEwxbRALQNDOU5Pwis+xWsdK8hOe0773OTjRzUC8G74Swj9aMn+GjGABdO2Aw/g2gyN8nKzRId5KlJ+BkYq93n9ldlrDE9qfPYtJ3NUTNF3E2TI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PtJCBrJS; 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="PtJCBrJS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E78D91F00A3D; Mon, 31 Aug 2026 16:43:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788194597; bh=r9wluAFJS2Nqh+s4Pox+cpkqMASsj+3Aw+nqrka43x4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PtJCBrJStJoEpJuVC8FQpLCI/BfDi/j9vi8InnDJTXxyJx867e5BqS9LHmGmOEuuY o9+5iejLVAM8h6SMG5dI2l/yJk6KiiX04ogzi1vkr0IWjImwDR8R5d+/GBDq+E0JkZ mcgoN1NpGCfWRuUhs7qoFRtswofe8GfJFGpBrpryaWzZZwamR582nhaw3OrW++jHTT 1Gb5fZhwEK6fk7tnED5JWG4DMpOb+/nwEApfozkJvkhf3QxSNmIP7NkxGgsU+72BAm H+DMbvevfFZ2qxku5dJpDbHOQp+vhg51JrDYy8gJHCxx9VaryYD60ATvKSIQO5zUmz +Po1HJOu+dXxw== From: Sasha Levin To: stable@vger.kernel.org Cc: Miklos Szeredi , zdi-disclosures@trendmicro.com, Sasha Levin Subject: [PATCH 6.18.y 3/3] fuse: fix race between interrupt and resend Date: Mon, 31 Aug 2026 12:43:13 -0400 Message-ID: <20260831164313.270365-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260831164313.270365-1-sashal@kernel.org> References: <2026083132-jaybird-willed-acf3@gregkh> <20260831164313.270365-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Miklos Szeredi [ Upstream commit ed9c881f3b498383f73c42712b359419da42a7b0 ] After commit f8fce75fedf7 ("fuse: clear intr_entry in fuse_resend and fuse_remove_pending_req") the WARN_ON(!list_empty(&req->intr_entry)) in fuse_request_free() still triggers due to the following race: In request_wait_answer() if (test_bit(FR_SENT, &req->flags)) -> returns true In fuse_chan_resend() clear_bit(FR_SENT, &req->flags) In request_wait_answer() queue_interrupt(req) Fix by: - move clearing FR_SENT inside fpq->lock - move setting FR_PENDING inside fiq->lock - recheck FR_SENT after acquiring fiq->lock in fuse_dev_queue_interrupt() Reported-by: zdi-disclosures@trendmicro.com Fixes: f8fce75fedf7 ("fuse: clear intr_entry in fuse_resend and fuse_remove_pending_req") Cc: stable@vger.kernel.org # 6.9 Signed-off-by: Miklos Szeredi [ adjusted context to use `fc->iq` in `fuse_resend()` since `struct fuse_chan` doesn't exist in this tree ] Signed-off-by: Sasha Levin --- fs/fuse/dev.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 8a38a263295fe..8bbff1f19d6bd 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -353,7 +353,8 @@ void fuse_dev_queue_forget(struct fuse_iqueue *fiq, void fuse_dev_queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) { spin_lock(&fiq->lock); - if (list_empty(&req->intr_entry)) { + /* Repeat FR_SENT test after obtaining the lock to prevent race with fuse_resend() */ + if (list_empty(&req->intr_entry) && test_bit(FR_SENT, &req->flags)) { list_add_tail(&req->intr_entry, &fiq->interrupts); /* * Pairs with smp_mb() implied by test_and_set_bit() @@ -2010,7 +2011,7 @@ static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, static void fuse_resend(struct fuse_conn *fc) { struct fuse_dev *fud; - struct fuse_req *req, *next; + struct fuse_req *req; struct fuse_iqueue *fiq = &fc->iq; LIST_HEAD(to_queue); unsigned int i; @@ -2025,24 +2026,20 @@ static void fuse_resend(struct fuse_conn *fc) struct fuse_pqueue *fpq = &fud->pq; spin_lock(&fpq->lock); - for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) - list_splice_tail_init(&fpq->processing[i], &to_queue); + for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) { + struct list_head *this_queue = &fpq->processing[i]; + + list_for_each_entry(req, this_queue, list) + clear_bit(FR_SENT, &req->flags); + list_splice_tail_init(this_queue, &to_queue); + } spin_unlock(&fpq->lock); } spin_unlock(&fc->lock); - list_for_each_entry_safe(req, next, &to_queue, list) { - set_bit(FR_PENDING, &req->flags); - clear_bit(FR_SENT, &req->flags); - /* mark the request as resend request */ - req->in.h.unique |= FUSE_UNIQUE_RESEND; - } - spin_lock(&fiq->lock); if (!fiq->connected) { spin_unlock(&fiq->lock); - list_for_each_entry(req, &to_queue, list) - clear_bit(FR_PENDING, &req->flags); fuse_dev_end_requests(&to_queue); return; } @@ -2051,6 +2048,10 @@ static void fuse_resend(struct fuse_conn *fc) * intr_entry on fiq->interrupts after the request is re-queued. */ list_for_each_entry(req, &to_queue, list) { + set_bit(FR_PENDING, &req->flags); + /* mark the request as resend request */ + req->in.h.unique |= FUSE_UNIQUE_RESEND; + if (test_bit(FR_INTERRUPTED, &req->flags)) list_del_init(&req->intr_entry); } -- 2.53.0