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 5C4552EBB8D for ; Mon, 31 Aug 2026 12:22:44 +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=1788178965; cv=none; b=drqLIl4RLnEFDNWLaKjSxGP3Qjr1gy5n2KgmOX5OuBqiDOEiL8hBS1Qx6EFGmdgTgHLVxUpIMjK3IKjg8QHh04ks4v88it9MoZ7tedRai1LjI28VAeAIGODQ2VoWK0S+eXSXnMrdrt042zYkfwJyJQfMKLxgNH1EDBfxmeMktN0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788178965; c=relaxed/simple; bh=442T1xF/PGB2yafs6qcKMQLREncdkx1ZYFgdNVKASUA=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=n38Vd9ht/OqvS09WPFJNI6J3s8Qr/uVf0UWJc4vf6iNR+AXv6G+6IX6IyAnu8WSvpaCGQiUWMOI4Bpr+Ki0j1rI6Be+NvQp2aeC70LyaW3OOQFWw3yxhIsPBbhcQxMhM+8ze44EhjxHI73Al4VdJz5gpjLquBBKU6wZCpJcNENc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=L2uSHis9; 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="L2uSHis9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1AA61F000E9; Mon, 31 Aug 2026 12:22:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788178964; bh=NC7g0gKE+DxJ5jhm6FiKgD3TzShkuVIcVmNjkkjZUBM=; h=Subject:To:Cc:From:Date; b=L2uSHis9irFmu5+A/i3JjoCx8418FWMbhlO8z10XJ/Ie8dv1VWH6uIWDj4N9Ire1u yI+Bmdb8cylUCXQ3G4KAK2v0o1f2coPABk37TiFZoU7FfLRmIS/dvWdeK1lpUCxjXy CdbFItr1XnWuDrj4wId10AdhbZ0wH50IFGEW4alM= Subject: FAILED: patch "[PATCH] fuse: fix race between interrupt and resend" failed to apply to 6.18-stable tree To: mszeredi@redhat.com Cc: From: Date: Mon, 31 Aug 2026 14:22:32 +0200 Message-ID: <2026083132-jaybird-willed-acf3@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 6.18-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-6.18.y git checkout FETCH_HEAD git cherry-pick -x ed9c881f3b498383f73c42712b359419da42a7b0 # git commit -s git send-email --to '' --in-reply-to '2026083132-jaybird-willed-acf3@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From ed9c881f3b498383f73c42712b359419da42a7b0 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Thu, 9 Jul 2026 08:37:05 +0200 Subject: [PATCH] fuse: fix race between interrupt and resend 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 diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 5763a7cd3b37..7e81dea4f1c7 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -240,7 +240,8 @@ 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() @@ -1760,7 +1761,7 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 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 *fch) 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 *fch) * 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); }