From: Hannes Reinecke Date: Fri, 7 Apr 2017 07:34:17 +0000 (+0200) Subject: scsi: sg: close race condition in sg_remove_sfp_usercontext() X-Git-Tag: v3.16.85~24 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8d1f3b474a89b42f957ba3bae959dd3cd16531ca;p=thirdparty%2Fkernel%2Fstable.git scsi: sg: close race condition in sg_remove_sfp_usercontext() commit 97d27b0dd015e980ade63fda111fd1353276e28b upstream. 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 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 198e60a004a61..4a1a0d74a51f5 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -561,6 +561,7 @@ sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos) } else count = (old_hdr->result == 0) ? 0 : -EIO; sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); retval = count; free_old_hdr: kfree(old_hdr); @@ -601,6 +602,7 @@ sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp) } err_out: err2 = sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); return err ? : err2 ? : count; } @@ -835,6 +837,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp, if (k) { SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%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)) { @@ -844,6 +847,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp, } sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); return -ENODEV; } @@ -1367,6 +1371,7 @@ sg_rq_end_io_usercontext(struct work_struct *work) struct sg_fd *sfp = srp->parentfp; sg_finish_rem_req(srp); + sg_remove_request(sfp, srp); kref_put(&sfp->f_ref, sg_remove_sfp); } @@ -1876,8 +1881,6 @@ sg_finish_rem_req(Sg_request *srp) else sg_remove_scat(req_schp); - sg_remove_request(sfp, srp); - return ret; } @@ -2211,12 +2214,17 @@ sg_remove_sfp_usercontext(struct work_struct *work) struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work); struct sg_device *sdp = sfp->parentdp; Sg_request *srp; + unsigned long iflags; /* Cleanup any responses which were never read(). */ + write_lock_irqsave(&sfp->rq_list_lock, iflags); while (!list_empty(&sfp->rq_list)) { srp = list_first_entry(&sfp->rq_list, Sg_request, entry); sg_finish_rem_req(srp); + list_del(&srp->entry); + srp->parentfp = NULL; } + write_unlock_irqrestore(&sfp->rq_list_lock, iflags); if (sfp->reserve.bufflen > 0) { SCSI_LOG_TIMEOUT(6,