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 91DC548164E; Mon, 31 Aug 2026 13:37:54 +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=1788183476; cv=none; b=qrwOCimtfFtAX0bMZmZ8EzjHrexDY08nAo+JjKnT4PYkNyrhWvvOYjM2Grdgc7yyhB6BqeGEXqGBwbonF9zItSHIIUP6TESCA60GELItyGPycuz4NMm2JysXLU5nWm7hHbhzhMkxEPYAoqMN5d8vWPE3+nrCMGESg07XtK3RANM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788183476; c=relaxed/simple; bh=F5BCNe0l9SOqLED3yKxTwxK4NNtEnCnI8+79xPiJRjw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bddBsZkDrVN0nhdN+7z4oA2sVcyY5AytOvkL0Ga1G6ikI2d0lrzjACd3fMVOL69RUib5vXT0pSM1K+YHw9W6Bh3F+guGnOIW1tAPaqcheyG8iDnjLrV3Y5xdJ6XKblqurh4pRAEhfvaWBVoMT+6afGfZu/30d3any5fQwwvRuaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0EaazbuF; 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="0EaazbuF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B12FE1F00A3D; Mon, 31 Aug 2026 13:37:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788183474; bh=qLYk5ToTfQECdew/D/SaEbtlwAYrayK/hPMwW9Zu0Fo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0EaazbuF5NiPsF1OCcC+cQPrf0NjMHITFb6xsVeHSYSyLCKFC7n6M2MIWtkyy9pJG bidHJHlCzfiY0DcTMaNxJBmZaHp4aQ+oJC/MYQ1wDJ0G0NtW9IZzyRQXUcP526uhV0 BYUanJVzsIPXNf83SRD8dyeuaOsoA4W/qIH62XLY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, zdi-disclosures@trendmicro.com, Miklos Szeredi Subject: [PATCH 7.2 12/71] fuse: fix race between interrupt and resend Date: Mon, 31 Aug 2026 15:33:37 +0200 Message-ID: <20260831133359.605466985@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260831133359.055927882@linuxfoundation.org> References: <20260831133359.055927882@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miklos Szeredi commit ed9c881f3b498383f73c42712b359419da42a7b0 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- fs/fuse/dev.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -240,7 +240,8 @@ void fuse_dev_queue_forget(struct fuse_i 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() @@ -1760,7 +1761,7 @@ out: void fuse_chan_resend(struct fuse_chan *fch) { struct fuse_dev *fud; - struct fuse_req *req, *next; + struct fuse_req *req; struct fuse_iqueue *fiq = &fch->iq; LIST_HEAD(to_queue); unsigned int i; @@ -1775,24 +1776,20 @@ void fuse_chan_resend(struct fuse_chan * 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(&fch->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; } @@ -1801,6 +1798,10 @@ void fuse_chan_resend(struct fuse_chan * * 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); }