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Groups > linux.kernel > #1593437

[PATCH 07/29] drivers, md: convert dm_dev_internal.count from atomic_t to refcount_t

From Elena Reshetova <elena.reshetova@intel.com>
Newsgroups linux.kernel
Subject [PATCH 07/29] drivers, md: convert dm_dev_internal.count from atomic_t to refcount_t
Date 2017-03-06 15:40 +0100
Message-ID <ti1XR-146-43@gated-at.bofh.it> (permalink)
References <ti1O9-Yn-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
---
 drivers/md/dm-table.c | 6 +++---
 drivers/md/dm.h       | 3 ++-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 3ad16d9..d2e2741 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -416,15 +416,15 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 			return r;
 		}
 
-		atomic_set(&dd->count, 0);
+		refcount_set(&dd->count, 1);
 		list_add(&dd->list, &t->devices);
 
 	} else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
 		r = upgrade_mode(dd, mode, t->md);
 		if (r)
 			return r;
+		refcount_inc(&dd->count);
 	}
-	atomic_inc(&dd->count);
 
 	*result = dd->dm_dev;
 	return 0;
@@ -478,7 +478,7 @@ void dm_put_device(struct dm_target *ti, struct dm_dev *d)
 		       dm_device_name(ti->table->md), d->name);
 		return;
 	}
-	if (atomic_dec_and_test(&dd->count)) {
+	if (refcount_dec_and_test(&dd->count)) {
 		dm_put_table_device(ti->table->md, d);
 		list_del(&dd->list);
 		kfree(dd);
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index f298b01..63b8142 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -19,6 +19,7 @@
 #include <linux/hdreg.h>
 #include <linux/completion.h>
 #include <linux/kobject.h>
+#include <linux/refcount.h>
 
 #include "dm-stats.h"
 
@@ -38,7 +39,7 @@
  */
 struct dm_dev_internal {
 	struct list_head list;
-	atomic_t count;
+	refcount_t count;
 	struct dm_dev *dm_dev;
 };
 
-- 
2.7.4

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Thread

[PATCH 00/29] drivers, mics refcount conversions Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:30 +0100
  [PATCH 08/29] drivers, md: convert mddev.active from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:30 +0100
    Re: [PATCH 08/29] drivers, md: convert mddev.active from atomic_t to  refcount_t Shaohua Li <shli@kernel.org> - 2017-03-07 20:20 +0100
      RE: [PATCH 08/29] drivers, md: convert mddev.active from atomic_t  to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-08 10:50 +0100
        Re: [PATCH 08/29] drivers, md: convert mddev.active from atomic_t to  refcount_t "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org> - 2017-03-08 11:30 +0100
  [PATCH 10/29] drivers, md: convert stripe_head.count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:30 +0100
    Re: [PATCH 10/29] drivers, md: convert stripe_head.count from  atomic_t to refcount_t Shaohua Li <shli@kernel.org> - 2017-03-07 20:20 +0100
      RE: [PATCH 10/29] drivers, md: convert stripe_head.count from  atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-08 10:50 +0100
  [PATCH 26/29] drivers, usb: convert dev_data.count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:30 +0100
  [PATCH 06/29] drivers, md: convert dm_cache_metadata.ref_count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:30 +0100
  [PATCH 24/29] drivers: convert iblock_req.pending from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:30 +0100
    Re: [PATCH 24/29] drivers: convert iblock_req.pending from atomic_t  to refcount_t "Nicholas A. Bellinger" <nab@linux-iscsi.org> - 2017-03-08 08:50 +0100
  [PATCH 02/29] drivers, firewire: convert fw_node.ref_count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:30 +0100
  [PATCH 13/29] drivers, media: convert vb2_vmarea_handler.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
    Re: [PATCH 13/29] drivers, media: convert  vb2_vmarea_handler.refcount from atomic_t to refcount_t Sakari Ailus <sakari.ailus@iki.fi> - 2017-03-07 10:00 +0100
      RE: [PATCH 13/29] drivers, media: convert  vb2_vmarea_handler.refcount from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-07 16:00 +0100
  [PATCH 16/29] drivers, media: convert vb2_vmalloc_buf.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 15/29] drivers, media: convert vb2_dma_sg_buf.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 22/29] drivers, scsi: convert iscsi_task.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
    Re: [PATCH 22/29] drivers, scsi: convert iscsi_task.refcount from  atomic_t to refcount_t Chris Leech <cleech@redhat.com> - 2017-03-08 19:50 +0100
      RE: [PATCH 22/29] drivers, scsi: convert iscsi_task.refcount from  atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-09 08:30 +0100
        Re: [PATCH 22/29] drivers, scsi: convert iscsi_task.refcount from  atomic_t to refcount_t Johannes Thumshirn <jthumshirn@suse.de> - 2017-03-09 09:50 +0100
          RE: [PATCH 22/29] drivers, scsi: convert iscsi_task.refcount from  atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-09 10:30 +0100
            Re: [PATCH 22/29] drivers, scsi: convert iscsi_task.refcount from  atomic_t to refcount_t Johannes Thumshirn <jthumshirn@suse.de> - 2017-03-09 10:40 +0100
  [PATCH 27/29] drivers, usb: convert ep_data.count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 19/29] drivers, s390: convert lcs_reply.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 21/29] drivers, s390: convert fc_fcp_pkt.ref_cnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
    Re: [PATCH 21/29] drivers, s390: convert fc_fcp_pkt.ref_cnt from  atomic_t to refcount_t Johannes Thumshirn <jthumshirn@suse.de> - 2017-03-06 16:30 +0100
      Re: [PATCH 21/29] drivers, s390: convert fc_fcp_pkt.ref_cnt from  atomic_t to refcount_t Benjamin Block <bblock@linux.vnet.ibm.com> - 2017-03-06 20:50 +0100
      RE: [PATCH 21/29] drivers, s390: convert fc_fcp_pkt.ref_cnt from  atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-07 12:20 +0100
      RE: [PATCH 21/29] drivers, s390: convert fc_fcp_pkt.ref_cnt from  atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-08 15:00 +0100
        Re: [PATCH 21/29] drivers, s390: convert fc_fcp_pkt.ref_cnt from  atomic_t to refcount_t Johannes Thumshirn <jthumshirn@suse.de> - 2017-03-08 16:30 +0100
  [PATCH 23/29] drivers: convert vme_user_vma_priv.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 14/29] drivers, media: convert vb2_dc_buf.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 04/29] drivers, connector: convert cn_callback_entry.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 05/29] drivers, md, bcache: convert cached_dev.count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 17/29] drivers, pci: convert hv_pci_dev.refs from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
    Re: [PATCH 17/29] drivers, pci: convert hv_pci_dev.refs from  atomic_t to refcount_t Bjorn Helgaas <helgaas@kernel.org> - 2017-03-06 23:30 +0100
      Re: [PATCH 17/29] drivers, pci: convert hv_pci_dev.refs from  atomic_t to refcount_t Stephen Hemminger <stephen@networkplumber.org> - 2017-03-07 21:00 +0100
  [PATCH 20/29] drivers, s390: convert qeth_reply.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 07/29] drivers, md: convert dm_dev_internal.count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 29/29] drivers, xen: convert grant_map.users from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
    Re: [Xen-devel] [PATCH 29/29] drivers, xen: convert grant_map.users  from atomic_t to refcount_t Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-03-06 19:50 +0100
      RE: [Xen-devel] [PATCH 29/29] drivers, xen: convert grant_map.users  from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-08 15:10 +0100
        Re: [Xen-devel] [PATCH 29/29] drivers, xen: convert grant_map.users  from atomic_t to refcount_t Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-03-08 18:50 +0100
          RE: [Xen-devel] [PATCH 29/29] drivers, xen: convert grant_map.users  from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-09 08:30 +0100
  [PATCH 25/29] drivers, usb: convert ffs_data.ref from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 28/29] drivers: convert sbd_duart.map_guard from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:40 +0100
  [PATCH 09/29] drivers, md: convert table_device.count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:50 +0100
  [PATCH 01/29] drivers, block: convert xen_blkif.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:50 +0100
  [PATCH 18/29] drivers, s390: convert urdev.ref_count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 15:50 +0100
  [PATCH 03/29] drivers, char: convert vma_data.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-06 16:30 +0100

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