Return-Path: Received: from mail-by2nam03on0127.outbound.protection.outlook.com ([104.47.42.127]:45712 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S966167AbeCHFFL (ORCPT ); Thu, 8 Mar 2018 00:05:11 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Hannes Reinecke , Hannes Reinecke , "Martin K . Petersen" , Sasha Levin Subject: [PATCH AUTOSEL for 4.4 006/101] scsi: sg: close race condition in sg_remove_sfp_usercontext() Date: Thu, 8 Mar 2018 05:01:10 +0000 Message-ID: <20180308050023.8548-6-alexander.levin@microsoft.com> References: <20180308050023.8548-1-alexander.levin@microsoft.com> In-Reply-To: <20180308050023.8548-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Hannes Reinecke [ Upstream commit 97d27b0dd015e980ade63fda111fd1353276e28b ] sg_remove_sfp_usercontext() is clearing any sg requests, but needs to take 'rq_list_lock' when modifying the list. Reported-by: Christoph Hellwig Signed-off-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Tested-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/sg.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 27f92f4ea6bc..dedaf3e89bb5 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -535,6 +535,7 @@ sg_read(struct file *filp, char __user *buf, size_t cou= nt, loff_t * ppos) } else count =3D (old_hdr->result =3D=3D 0) ? 0 : -EIO; sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); retval =3D count; free_old_hdr: kfree(old_hdr); @@ -575,6 +576,7 @@ sg_new_read(Sg_fd * sfp, char __user *buf, size_t count= , Sg_request * srp) } err_out: err2 =3D sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); return err ? : err2 ? : count; } =20 @@ -811,6 +813,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp, SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp, "sg_common_write: start_req err=3D%d\n", k)); sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); return k; /* probably out of space --> ENOMEM */ } if (atomic_read(&sdp->detaching)) { @@ -823,6 +826,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp, } =20 sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); return -ENODEV; } =20 @@ -1312,6 +1316,7 @@ sg_rq_end_io_usercontext(struct work_struct *work) struct sg_fd *sfp =3D srp->parentfp; =20 sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); kref_put(&sfp->f_ref, sg_remove_sfp); } =20 @@ -1856,8 +1861,6 @@ sg_finish_rem_req(Sg_request *srp) else sg_remove_scat(sfp, req_schp); =20 - sg_remove_request(sfp, srp); - return ret; } =20 @@ -2204,12 +2207,17 @@ sg_remove_sfp_usercontext(struct work_struct *work) struct sg_fd *sfp =3D container_of(work, struct sg_fd, ew.work); struct sg_device *sdp =3D sfp->parentdp; Sg_request *srp; + unsigned long iflags; =20 /* Cleanup any responses which were never read(). */ + write_lock_irqsave(&sfp->rq_list_lock, iflags); while (!list_empty(&sfp->rq_list)) { srp =3D list_first_entry(&sfp->rq_list, Sg_request, entry); sg_finish_rem_req(srp); + list_del(&srp->entry); + srp->parentfp =3D NULL; } + write_unlock_irqrestore(&sfp->rq_list_lock, iflags); =20 if (sfp->reserve.bufflen > 0) { SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp, --=20 2.14.1