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 07DB3AD58; Wed, 19 Jun 2024 13:16:36 +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=1718802996; cv=none; b=Gh7Nv8lZEtZRwh2uZZaKoPOIGc0dOeo6qmX7pKd/E0Zn158FMA1YpCMwX4BzoJTbyG0XC4wbbF9CHJPl2vE+EVZsi96u2fszEuWOffXvelYUJ4L1INicyay/goEU+rZKm5iPpWEQcDIiysFZDymEA8dkFXhbJ1V5u9A83/V8LIo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718802996; c=relaxed/simple; bh=OsEqO6e2o7BeV+tgcEcGdayN3SnJE/cfhrJbhadz65Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=C7GxgFB1zL1YjG4NH0hAj0cL1MRKrdAlvZAzDvQymbYOcYkqcJuIyzyDqESJVJzOPux2yP5E5WkaLT9jlwM1tU47Kr3J1VDzcpSxFLUrfB5wtZCpgsPGuKl84kAeZCWoK26O6w/ZjYrJrJPLJDsP74bXLXc5P1Y3SO5MIPlSrwo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=z7rBPNtA; 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="z7rBPNtA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70B3BC2BBFC; Wed, 19 Jun 2024 13:16:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718802995; bh=OsEqO6e2o7BeV+tgcEcGdayN3SnJE/cfhrJbhadz65Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=z7rBPNtAL+SzAxJvnbXPDCz6L5zcWP5gAqyNuy0oqx2+BUAmkYk3m1W+unXE+r56D GbCqcr80vvFQK48gBi17r3WEAjqRSYDhIL47sRC3CjQphfq/LAru8g09ZzqIP/xJ8y j1LvCzkiJJ/G6kYZ7FtJKYZBF/cvplNdiYllvwyc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Baokun Li , Jeff Layton , Christian Brauner , Sasha Levin Subject: [PATCH 6.9 118/281] cachefiles: flush all requests after setting CACHEFILES_DEAD Date: Wed, 19 Jun 2024 14:54:37 +0200 Message-ID: <20240619125614.387549928@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240619125609.836313103@linuxfoundation.org> References: <20240619125609.836313103@linuxfoundation.org> User-Agent: quilt/0.67 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 6.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li [ Upstream commit 85e833cd7243bda7285492b0653c3abb1e2e757b ] In ondemand mode, when the daemon is processing an open request, if the kernel flags the cache as CACHEFILES_DEAD, the cachefiles_daemon_write() will always return -EIO, so the daemon can't pass the copen to the kernel. Then the kernel process that is waiting for the copen triggers a hung_task. Since the DEAD state is irreversible, it can only be exited by closing /dev/cachefiles. Therefore, after calling cachefiles_io_error() to mark the cache as CACHEFILES_DEAD, if in ondemand mode, flush all requests to avoid the above hungtask. We may still be able to read some of the cached data before closing the fd of /dev/cachefiles. Note that this relies on the patch that adds reference counting to the req, otherwise it may UAF. Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie") Signed-off-by: Baokun Li Link: https://lore.kernel.org/r/20240522114308.2402121-12-libaokun@huaweicloud.com Acked-by: Jeff Layton Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- fs/cachefiles/daemon.c | 2 +- fs/cachefiles/internal.h | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index ccb7b707ea4b7..06cdf1a8a16f6 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -133,7 +133,7 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) return 0; } -static void cachefiles_flush_reqs(struct cachefiles_cache *cache) +void cachefiles_flush_reqs(struct cachefiles_cache *cache) { struct xarray *xa = &cache->reqs; struct cachefiles_req *req; diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 45c8bed605383..6845a90cdfcce 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -188,6 +188,7 @@ extern int cachefiles_has_space(struct cachefiles_cache *cache, * daemon.c */ extern const struct file_operations cachefiles_daemon_fops; +extern void cachefiles_flush_reqs(struct cachefiles_cache *cache); extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache); extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache); @@ -426,6 +427,8 @@ do { \ pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \ fscache_io_error((___cache)->cache); \ set_bit(CACHEFILES_DEAD, &(___cache)->flags); \ + if (cachefiles_in_ondemand_mode(___cache)) \ + cachefiles_flush_reqs(___cache); \ } while (0) #define cachefiles_io_error_obj(object, FMT, ...) \ -- 2.43.0