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 99A238476 for ; Tue, 28 Mar 2023 14:55:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FFAAC433D2; Tue, 28 Mar 2023 14:55:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680015317; bh=k1N7dHmalUzQgKvoTbPJ0heyvLSaRgpyQcstFsWvkUU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cj7s4KjZU2bliGhRN3dKl5IMoK+jbbGi/Q86ztt9CWGhJM5TjS20hp36RZzzjHIFp zs/DVeBobnyWsugi9QlxG7MRiCoFLIf56TLodZuhuMvAK5ixZJGTdUK7Qct9czfxPk m8RfKoszIiT+/mYKnH59LhefCLUMPbnkfhpJS5J4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hou Tao , Ignat Korchagin , Mike Snitzer Subject: [PATCH 6.2 238/240] dm crypt: avoid accessing uninitialized tasklet Date: Tue, 28 Mar 2023 16:43:21 +0200 Message-Id: <20230328142629.607611853@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230328142619.643313678@linuxfoundation.org> References: <20230328142619.643313678@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Mike Snitzer commit d9a02e016aaf5a57fb44e9a5e6da8ccd3b9e2e70 upstream. When neither "no_read_workqueue" nor "no_write_workqueue" are enabled, tasklet_trylock() in crypt_dec_pending() may still return false due to an uninitialized state, and dm-crypt will unnecessarily do io completion in io_queue workqueue instead of current context. Fix this by adding an 'in_tasklet' flag to dm_crypt_io struct and initialize it to false in crypt_io_init(). Set this flag to true in kcryptd_queue_crypt() before calling tasklet_schedule(). If set crypt_dec_pending() will punt io completion to a workqueue. This also nicely avoids the tasklet_trylock/unlock hack when tasklets aren't in use. Fixes: 8e14f610159d ("dm crypt: do not call bio_endio() from the dm-crypt tasklet") Cc: stable@vger.kernel.org Reported-by: Hou Tao Suggested-by: Ignat Korchagin Reviewed-by: Ignat Korchagin Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-crypt.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -71,7 +71,9 @@ struct dm_crypt_io { struct crypt_config *cc; struct bio *base_bio; u8 *integrity_metadata; - bool integrity_metadata_from_pool; + bool integrity_metadata_from_pool:1; + bool in_tasklet:1; + struct work_struct work; struct tasklet_struct tasklet; @@ -1728,6 +1730,7 @@ static void crypt_io_init(struct dm_cryp io->ctx.r.req = NULL; io->integrity_metadata = NULL; io->integrity_metadata_from_pool = false; + io->in_tasklet = false; atomic_set(&io->io_pending, 0); } @@ -1773,14 +1776,13 @@ static void crypt_dec_pending(struct dm_ * our tasklet. In this case we need to delay bio_endio() * execution to after the tasklet is done and dequeued. */ - if (tasklet_trylock(&io->tasklet)) { - tasklet_unlock(&io->tasklet); - bio_endio(base_bio); + if (io->in_tasklet) { + INIT_WORK(&io->work, kcryptd_io_bio_endio); + queue_work(cc->io_queue, &io->work); return; } - INIT_WORK(&io->work, kcryptd_io_bio_endio); - queue_work(cc->io_queue, &io->work); + bio_endio(base_bio); } /* @@ -2229,6 +2231,7 @@ static void kcryptd_queue_crypt(struct d * it is being executed with irqs disabled. */ if (in_hardirq() || irqs_disabled()) { + io->in_tasklet = true; tasklet_init(&io->tasklet, kcryptd_crypt_tasklet, (unsigned long)&io->work); tasklet_schedule(&io->tasklet); return;