* [PATCH 0/5] fs, xfs atomic_t to refcount_t conversions version 2
@ 2017-03-01 8:47 Elena Reshetova
2017-03-01 8:47 ` [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t Elena Reshetova
` (4 more replies)
0 siblings, 5 replies; 12+ messages in thread
From: Elena Reshetova @ 2017-03-01 8:47 UTC (permalink / raw)
To: linux-kernel
Cc: linux-xfs, peterz, gregkh, darrick.wong, david, Elena Reshetova
changes in v2:
* removed two patches that actually caused problems in testing and
there didn't seem to be a resonable way to convert them to refcount_t
based on all the triggered issues.
* run xfstests with TEST and SCRATCH partitions enabled, XFS_DEBUG on,
and WARNs on refcount_t API on. No issues found in the log upon execution.
Some random test failures (based on different runs) and stress tests do not always
pass, but again, no issues on refcounts noticed anywhere.
Now when new refcount_t type and API are finally merged
(see include/linux/refcount.h), the following
patches convert various refcounters in the fs/xfs susystem from atomic_t
to refcount_t. By doing this we prevent intentional or accidental
underflows or overflows that can led to use-after-free vulnerabilities.
The below patches are fully independent and can be cherry-picked separately.
Since we convert all kernel subsystems in the same fashion, resulting
in about 300 patches, we have to group them for sending at least in some
fashion to be manageable. Please excuse the long cc list.
Elena Reshetova (5):
fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to
refcount_t
fs, xfs: convert xfs_efi_log_item.efi_refcount from atomic_t to
refcount_t
fs, xfs: convert xlog_ticket.t_ref from atomic_t to refcount_t
fs, xfs: convert xfs_cui_log_item.cui_refcount from atomic_t to
refcount_t
fs, xfs: convert xfs_rui_log_item.rui_refcount from atomic_t to
refcount_t
fs/xfs/xfs_bmap_item.c | 4 ++--
fs/xfs/xfs_bmap_item.h | 4 +++-
fs/xfs/xfs_extfree_item.c | 4 ++--
fs/xfs/xfs_extfree_item.h | 4 +++-
fs/xfs/xfs_log.c | 10 +++++-----
fs/xfs/xfs_log_priv.h | 4 +++-
fs/xfs/xfs_refcount_item.c | 4 ++--
fs/xfs/xfs_refcount_item.h | 4 +++-
fs/xfs/xfs_rmap_item.c | 4 ++--
fs/xfs/xfs_rmap_item.h | 4 +++-
10 files changed, 28 insertions(+), 18 deletions(-)
--
2.7.4
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t
2017-03-01 8:47 [PATCH 0/5] fs, xfs atomic_t to refcount_t conversions version 2 Elena Reshetova
@ 2017-03-01 8:47 ` Elena Reshetova
2017-03-01 8:47 ` [PATCH 2/5] fs, xfs: convert xfs_efi_log_item.efi_refcount " Elena Reshetova
` (3 subsequent siblings)
4 siblings, 0 replies; 12+ messages in thread
From: Elena Reshetova @ 2017-03-01 8:47 UTC (permalink / raw)
To: linux-kernel
Cc: linux-xfs, peterz, gregkh, darrick.wong, david, Elena Reshetova,
Hans Liljestrand, Kees Cook, David Windsor
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>
---
fs/xfs/xfs_bmap_item.c | 4 ++--
fs/xfs/xfs_bmap_item.h | 4 +++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 9bf57c7..33104ad 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -199,7 +199,7 @@ xfs_bui_init(
buip->bui_format.bui_nextents = XFS_BUI_MAX_FAST_EXTENTS;
buip->bui_format.bui_id = (uintptr_t)(void *)buip;
atomic_set(&buip->bui_next_extent, 0);
- atomic_set(&buip->bui_refcount, 2);
+ refcount_set(&buip->bui_refcount, 2);
return buip;
}
@@ -215,7 +215,7 @@ void
xfs_bui_release(
struct xfs_bui_log_item *buip)
{
- if (atomic_dec_and_test(&buip->bui_refcount)) {
+ if (refcount_dec_and_test(&buip->bui_refcount)) {
xfs_trans_ail_remove(&buip->bui_item, SHUTDOWN_LOG_IO_ERROR);
xfs_bui_item_free(buip);
}
diff --git a/fs/xfs/xfs_bmap_item.h b/fs/xfs/xfs_bmap_item.h
index c867daa..988a6ae 100644
--- a/fs/xfs/xfs_bmap_item.h
+++ b/fs/xfs/xfs_bmap_item.h
@@ -20,6 +20,8 @@
#ifndef __XFS_BMAP_ITEM_H__
#define __XFS_BMAP_ITEM_H__
+#include <linux/refcount.h>
+
/*
* There are (currently) two pairs of bmap btree redo item types: map & unmap.
* The common abbreviations for these are BUI (bmap update intent) and BUD
@@ -61,7 +63,7 @@ struct kmem_zone;
*/
struct xfs_bui_log_item {
struct xfs_log_item bui_item;
- atomic_t bui_refcount;
+ refcount_t bui_refcount;
atomic_t bui_next_extent;
unsigned long bui_flags; /* misc flags */
struct xfs_bui_log_format bui_format;
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH 2/5] fs, xfs: convert xfs_efi_log_item.efi_refcount from atomic_t to refcount_t
2017-03-01 8:47 [PATCH 0/5] fs, xfs atomic_t to refcount_t conversions version 2 Elena Reshetova
2017-03-01 8:47 ` [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t Elena Reshetova
@ 2017-03-01 8:47 ` Elena Reshetova
2017-03-01 8:47 ` [PATCH 3/5] fs, xfs: convert xlog_ticket.t_ref " Elena Reshetova
` (2 subsequent siblings)
4 siblings, 0 replies; 12+ messages in thread
From: Elena Reshetova @ 2017-03-01 8:47 UTC (permalink / raw)
To: linux-kernel
Cc: linux-xfs, peterz, gregkh, darrick.wong, david, Elena Reshetova,
Hans Liljestrand, Kees Cook, David Windsor
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>
---
fs/xfs/xfs_extfree_item.c | 4 ++--
fs/xfs/xfs_extfree_item.h | 4 +++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index d7bc149..4e0acf0 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -220,7 +220,7 @@ xfs_efi_init(
efip->efi_format.efi_nextents = nextents;
efip->efi_format.efi_id = (uintptr_t)(void *)efip;
atomic_set(&efip->efi_next_extent, 0);
- atomic_set(&efip->efi_refcount, 2);
+ refcount_set(&efip->efi_refcount, 2);
return efip;
}
@@ -290,7 +290,7 @@ void
xfs_efi_release(
struct xfs_efi_log_item *efip)
{
- if (atomic_dec_and_test(&efip->efi_refcount)) {
+ if (refcount_dec_and_test(&efip->efi_refcount)) {
xfs_trans_ail_remove(&efip->efi_item, SHUTDOWN_LOG_IO_ERROR);
xfs_efi_item_free(efip);
}
diff --git a/fs/xfs/xfs_extfree_item.h b/fs/xfs/xfs_extfree_item.h
index a32c794..e6da63d 100644
--- a/fs/xfs/xfs_extfree_item.h
+++ b/fs/xfs/xfs_extfree_item.h
@@ -18,6 +18,8 @@
#ifndef __XFS_EXTFREE_ITEM_H__
#define __XFS_EXTFREE_ITEM_H__
+#include <linux/refcount.h>
+
/* kernel only EFI/EFD definitions */
struct xfs_mount;
@@ -64,7 +66,7 @@ struct kmem_zone;
*/
typedef struct xfs_efi_log_item {
xfs_log_item_t efi_item;
- atomic_t efi_refcount;
+ refcount_t efi_refcount;
atomic_t efi_next_extent;
unsigned long efi_flags; /* misc flags */
xfs_efi_log_format_t efi_format;
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH 3/5] fs, xfs: convert xlog_ticket.t_ref from atomic_t to refcount_t
2017-03-01 8:47 [PATCH 0/5] fs, xfs atomic_t to refcount_t conversions version 2 Elena Reshetova
2017-03-01 8:47 ` [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t Elena Reshetova
2017-03-01 8:47 ` [PATCH 2/5] fs, xfs: convert xfs_efi_log_item.efi_refcount " Elena Reshetova
@ 2017-03-01 8:47 ` Elena Reshetova
2017-03-01 8:47 ` [PATCH 4/5] fs, xfs: convert xfs_cui_log_item.cui_refcount " Elena Reshetova
2017-03-01 8:47 ` [PATCH 5/5] fs, xfs: convert xfs_rui_log_item.rui_refcount " Elena Reshetova
4 siblings, 0 replies; 12+ messages in thread
From: Elena Reshetova @ 2017-03-01 8:47 UTC (permalink / raw)
To: linux-kernel
Cc: linux-xfs, peterz, gregkh, darrick.wong, david, Elena Reshetova,
Hans Liljestrand, Kees Cook, David Windsor
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>
---
fs/xfs/xfs_log.c | 10 +++++-----
fs/xfs/xfs_log_priv.h | 4 +++-
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index b1469f0..c127fa0 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -3500,8 +3500,8 @@ void
xfs_log_ticket_put(
xlog_ticket_t *ticket)
{
- ASSERT(atomic_read(&ticket->t_ref) > 0);
- if (atomic_dec_and_test(&ticket->t_ref))
+ ASSERT(refcount_read(&ticket->t_ref) > 0);
+ if (refcount_dec_and_test(&ticket->t_ref))
kmem_zone_free(xfs_log_ticket_zone, ticket);
}
@@ -3509,8 +3509,8 @@ xlog_ticket_t *
xfs_log_ticket_get(
xlog_ticket_t *ticket)
{
- ASSERT(atomic_read(&ticket->t_ref) > 0);
- atomic_inc(&ticket->t_ref);
+ ASSERT(refcount_read(&ticket->t_ref) > 0);
+ refcount_inc(&ticket->t_ref);
return ticket;
}
@@ -3632,7 +3632,7 @@ xlog_ticket_alloc(
unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
- atomic_set(&tic->t_ref, 1);
+ refcount_set(&tic->t_ref, 1);
tic->t_task = current;
INIT_LIST_HEAD(&tic->t_queue);
tic->t_unit_res = unit_res;
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index c2604a5..279afce 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -18,6 +18,8 @@
#ifndef __XFS_LOG_PRIV_H__
#define __XFS_LOG_PRIV_H__
+#include <linux/refcount.h>
+
struct xfs_buf;
struct xlog;
struct xlog_ticket;
@@ -168,7 +170,7 @@ typedef struct xlog_ticket {
struct list_head t_queue; /* reserve/write queue */
struct task_struct *t_task; /* task that owns this ticket */
xlog_tid_t t_tid; /* transaction identifier : 4 */
- atomic_t t_ref; /* ticket reference count : 4 */
+ refcount_t t_ref; /* ticket reference count : 4 */
int t_curr_res; /* current reservation in bytes : 4 */
int t_unit_res; /* unit reservation in bytes : 4 */
char t_ocnt; /* original count : 1 */
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH 4/5] fs, xfs: convert xfs_cui_log_item.cui_refcount from atomic_t to refcount_t
2017-03-01 8:47 [PATCH 0/5] fs, xfs atomic_t to refcount_t conversions version 2 Elena Reshetova
` (2 preceding siblings ...)
2017-03-01 8:47 ` [PATCH 3/5] fs, xfs: convert xlog_ticket.t_ref " Elena Reshetova
@ 2017-03-01 8:47 ` Elena Reshetova
2017-03-06 19:14 ` Darrick J. Wong
2017-03-01 8:47 ` [PATCH 5/5] fs, xfs: convert xfs_rui_log_item.rui_refcount " Elena Reshetova
4 siblings, 1 reply; 12+ messages in thread
From: Elena Reshetova @ 2017-03-01 8:47 UTC (permalink / raw)
To: linux-kernel
Cc: linux-xfs, peterz, gregkh, darrick.wong, david, Elena Reshetova,
Hans Liljestrand, Kees Cook, David Windsor
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>
---
fs/xfs/xfs_refcount_item.c | 4 ++--
fs/xfs/xfs_refcount_item.h | 4 +++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
index 6e4c744..61bc570 100644
--- a/fs/xfs/xfs_refcount_item.c
+++ b/fs/xfs/xfs_refcount_item.c
@@ -205,7 +205,7 @@ xfs_cui_init(
cuip->cui_format.cui_nextents = nextents;
cuip->cui_format.cui_id = (uintptr_t)(void *)cuip;
atomic_set(&cuip->cui_next_extent, 0);
- atomic_set(&cuip->cui_refcount, 2);
+ refcount_set(&cuip->cui_refcount, 2);
return cuip;
}
@@ -221,7 +221,7 @@ void
xfs_cui_release(
struct xfs_cui_log_item *cuip)
{
- if (atomic_dec_and_test(&cuip->cui_refcount)) {
+ if (refcount_dec_and_test(&cuip->cui_refcount)) {
xfs_trans_ail_remove(&cuip->cui_item, SHUTDOWN_LOG_IO_ERROR);
xfs_cui_item_free(cuip);
}
diff --git a/fs/xfs/xfs_refcount_item.h b/fs/xfs/xfs_refcount_item.h
index 5b74ddd..7f23ff8 100644
--- a/fs/xfs/xfs_refcount_item.h
+++ b/fs/xfs/xfs_refcount_item.h
@@ -20,6 +20,8 @@
#ifndef __XFS_REFCOUNT_ITEM_H__
#define __XFS_REFCOUNT_ITEM_H__
+#include <linux/refcount.h>
+
/*
* There are (currently) two pairs of refcount btree redo item types:
* increase and decrease. The log items for these are CUI (refcount
@@ -63,7 +65,7 @@ struct kmem_zone;
*/
struct xfs_cui_log_item {
struct xfs_log_item cui_item;
- atomic_t cui_refcount;
+ refcount_t cui_refcount;
atomic_t cui_next_extent;
unsigned long cui_flags; /* misc flags */
struct xfs_cui_log_format cui_format;
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH 5/5] fs, xfs: convert xfs_rui_log_item.rui_refcount from atomic_t to refcount_t
2017-03-01 8:47 [PATCH 0/5] fs, xfs atomic_t to refcount_t conversions version 2 Elena Reshetova
` (3 preceding siblings ...)
2017-03-01 8:47 ` [PATCH 4/5] fs, xfs: convert xfs_cui_log_item.cui_refcount " Elena Reshetova
@ 2017-03-01 8:47 ` Elena Reshetova
4 siblings, 0 replies; 12+ messages in thread
From: Elena Reshetova @ 2017-03-01 8:47 UTC (permalink / raw)
To: linux-kernel
Cc: linux-xfs, peterz, gregkh, darrick.wong, david, Elena Reshetova,
Hans Liljestrand, Kees Cook, David Windsor
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>
---
fs/xfs/xfs_rmap_item.c | 4 ++--
fs/xfs/xfs_rmap_item.h | 4 +++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_rmap_item.c b/fs/xfs/xfs_rmap_item.c
index 73c8278..5e1664a 100644
--- a/fs/xfs/xfs_rmap_item.c
+++ b/fs/xfs/xfs_rmap_item.c
@@ -204,7 +204,7 @@ xfs_rui_init(
ruip->rui_format.rui_nextents = nextents;
ruip->rui_format.rui_id = (uintptr_t)(void *)ruip;
atomic_set(&ruip->rui_next_extent, 0);
- atomic_set(&ruip->rui_refcount, 2);
+ refcount_set(&ruip->rui_refcount, 2);
return ruip;
}
@@ -243,7 +243,7 @@ void
xfs_rui_release(
struct xfs_rui_log_item *ruip)
{
- if (atomic_dec_and_test(&ruip->rui_refcount)) {
+ if (refcount_dec_and_test(&ruip->rui_refcount)) {
xfs_trans_ail_remove(&ruip->rui_item, SHUTDOWN_LOG_IO_ERROR);
xfs_rui_item_free(ruip);
}
diff --git a/fs/xfs/xfs_rmap_item.h b/fs/xfs/xfs_rmap_item.h
index 340c968..2529a35 100644
--- a/fs/xfs/xfs_rmap_item.h
+++ b/fs/xfs/xfs_rmap_item.h
@@ -20,6 +20,8 @@
#ifndef __XFS_RMAP_ITEM_H__
#define __XFS_RMAP_ITEM_H__
+#include <linux/refcount.h>
+
/*
* There are (currently) three pairs of rmap btree redo item types: map, unmap,
* and convert. The common abbreviations for these are RUI (rmap update
@@ -64,7 +66,7 @@ struct kmem_zone;
*/
struct xfs_rui_log_item {
struct xfs_log_item rui_item;
- atomic_t rui_refcount;
+ refcount_t rui_refcount;
atomic_t rui_next_extent;
unsigned long rui_flags; /* misc flags */
struct xfs_rui_log_format rui_format;
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH 4/5] fs, xfs: convert xfs_cui_log_item.cui_refcount from atomic_t to refcount_t
2017-03-01 8:47 ` [PATCH 4/5] fs, xfs: convert xfs_cui_log_item.cui_refcount " Elena Reshetova
@ 2017-03-06 19:14 ` Darrick J. Wong
2017-03-07 17:33 ` Reshetova, Elena
0 siblings, 1 reply; 12+ messages in thread
From: Darrick J. Wong @ 2017-03-06 19:14 UTC (permalink / raw)
To: Elena Reshetova
Cc: linux-kernel, linux-xfs, peterz, gregkh, david, Hans Liljestrand,
Kees Cook, David Windsor
On Wed, Mar 01, 2017 at 10:47:39AM +0200, Elena Reshetova wrote:
> 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>
> ---
> fs/xfs/xfs_refcount_item.c | 4 ++--
> fs/xfs/xfs_refcount_item.h | 4 +++-
> 2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
> index 6e4c744..61bc570 100644
> --- a/fs/xfs/xfs_refcount_item.c
> +++ b/fs/xfs/xfs_refcount_item.c
> @@ -205,7 +205,7 @@ xfs_cui_init(
> cuip->cui_format.cui_nextents = nextents;
> cuip->cui_format.cui_id = (uintptr_t)(void *)cuip;
> atomic_set(&cuip->cui_next_extent, 0);
> - atomic_set(&cuip->cui_refcount, 2);
> + refcount_set(&cuip->cui_refcount, 2);
I'm assuming the refcount design is ok with the log item refcounts
starting at 2 and marching down to zero? The code seems to be
fine with it; I just want to make sure everyone's ok with supporting
this use case.
> return cuip;
> }
> @@ -221,7 +221,7 @@ void
> xfs_cui_release(
> struct xfs_cui_log_item *cuip)
> {
> - if (atomic_dec_and_test(&cuip->cui_refcount)) {
> + if (refcount_dec_and_test(&cuip->cui_refcount)) {
I suppose it's useful to have refcount_dec_and_test complain loudly if
we ever have a dangling pointer... Friday I was chasing a possible
use-after-free of the EFI items in generic/388.
> xfs_trans_ail_remove(&cuip->cui_item, SHUTDOWN_LOG_IO_ERROR);
> xfs_cui_item_free(cuip);
> }
> diff --git a/fs/xfs/xfs_refcount_item.h b/fs/xfs/xfs_refcount_item.h
> index 5b74ddd..7f23ff8 100644
> --- a/fs/xfs/xfs_refcount_item.h
> +++ b/fs/xfs/xfs_refcount_item.h
> @@ -20,6 +20,8 @@
> #ifndef __XFS_REFCOUNT_ITEM_H__
> #define __XFS_REFCOUNT_ITEM_H__
>
> +#include <linux/refcount.h>
I still think this include should go in xfs_linux.h, the same as most of
the other linux/*.h includes in XFS.
--D
> +
> /*
> * There are (currently) two pairs of refcount btree redo item types:
> * increase and decrease. The log items for these are CUI (refcount
> @@ -63,7 +65,7 @@ struct kmem_zone;
> */
> struct xfs_cui_log_item {
> struct xfs_log_item cui_item;
> - atomic_t cui_refcount;
> + refcount_t cui_refcount;
> atomic_t cui_next_extent;
> unsigned long cui_flags; /* misc flags */
> struct xfs_cui_log_format cui_format;
> --
> 2.7.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 12+ messages in thread
* RE: [PATCH 4/5] fs, xfs: convert xfs_cui_log_item.cui_refcount from atomic_t to refcount_t
2017-03-06 19:14 ` Darrick J. Wong
@ 2017-03-07 17:33 ` Reshetova, Elena
2017-03-07 20:30 ` Darrick J. Wong
0 siblings, 1 reply; 12+ messages in thread
From: Reshetova, Elena @ 2017-03-07 17:33 UTC (permalink / raw)
To: Darrick J. Wong
Cc: linux-kernel, linux-xfs, peterz, gregkh, david, Hans Liljestrand,
Kees Cook, David Windsor
> 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>
> > ---
> > fs/xfs/xfs_refcount_item.c | 4 ++--
> > fs/xfs/xfs_refcount_item.h | 4 +++-
> > 2 files changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
> > index 6e4c744..61bc570 100644
> > --- a/fs/xfs/xfs_refcount_item.c
> > +++ b/fs/xfs/xfs_refcount_item.c
> > @@ -205,7 +205,7 @@ xfs_cui_init(
> > cuip->cui_format.cui_nextents = nextents;
> > cuip->cui_format.cui_id = (uintptr_t)(void *)cuip;
> > atomic_set(&cuip->cui_next_extent, 0);
> > - atomic_set(&cuip->cui_refcount, 2);
> > + refcount_set(&cuip->cui_refcount, 2);
>
> I'm assuming the refcount design is ok with the log item refcounts
> starting at 2 and marching down to zero? The code seems to be
> fine with it; I just want to make sure everyone's ok with supporting
> this use case.
Yes, as soon as it doesn't go beyond 0 or starting to increment again after reaching zero.
>
> > return cuip;
> > }
> > @@ -221,7 +221,7 @@ void
> > xfs_cui_release(
> > struct xfs_cui_log_item *cuip)
> > {
> > - if (atomic_dec_and_test(&cuip->cui_refcount)) {
> > + if (refcount_dec_and_test(&cuip->cui_refcount)) {
>
> I suppose it's useful to have refcount_dec_and_test complain loudly if
> we ever have a dangling pointer... Friday I was chasing a possible
> use-after-free of the EFI items in generic/388.
Currently it complains with WARN if it finds itself decrementing from zero.
There is patch in RFC stage also that would make it configurable: complain with WARN or complain/abort with BUG.
>
> > xfs_trans_ail_remove(&cuip->cui_item,
> SHUTDOWN_LOG_IO_ERROR);
> > xfs_cui_item_free(cuip);
> > }
> > diff --git a/fs/xfs/xfs_refcount_item.h b/fs/xfs/xfs_refcount_item.h
> > index 5b74ddd..7f23ff8 100644
> > --- a/fs/xfs/xfs_refcount_item.h
> > +++ b/fs/xfs/xfs_refcount_item.h
> > @@ -20,6 +20,8 @@
> > #ifndef __XFS_REFCOUNT_ITEM_H__
> > #define __XFS_REFCOUNT_ITEM_H__
> >
> > +#include <linux/refcount.h>
>
> I still think this include should go in xfs_linux.h, the same as most of
> the other linux/*.h includes in XFS.
Oh, very sorry, I forgot this one. Got too much focused on testing :(
Do you want me to resend with this change or can you take it in and do this small fix yourself?
Best Regards,
Elena.
>
> --D
>
> > +
> > /*
> > * There are (currently) two pairs of refcount btree redo item types:
> > * increase and decrease. The log items for these are CUI (refcount
> > @@ -63,7 +65,7 @@ struct kmem_zone;
> > */
> > struct xfs_cui_log_item {
> > struct xfs_log_item cui_item;
> > - atomic_t cui_refcount;
> > + refcount_t cui_refcount;
> > atomic_t cui_next_extent;
> > unsigned long cui_flags; /* misc
> flags */
> > struct xfs_cui_log_format cui_format;
> > --
> > 2.7.4
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 4/5] fs, xfs: convert xfs_cui_log_item.cui_refcount from atomic_t to refcount_t
2017-03-07 17:33 ` Reshetova, Elena
@ 2017-03-07 20:30 ` Darrick J. Wong
0 siblings, 0 replies; 12+ messages in thread
From: Darrick J. Wong @ 2017-03-07 20:30 UTC (permalink / raw)
To: Reshetova, Elena
Cc: linux-kernel, linux-xfs, peterz, gregkh, david, Hans Liljestrand,
Kees Cook, David Windsor
On Tue, Mar 07, 2017 at 05:33:14PM +0000, Reshetova, Elena wrote:
> > 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>
> > > ---
> > > fs/xfs/xfs_refcount_item.c | 4 ++--
> > > fs/xfs/xfs_refcount_item.h | 4 +++-
> > > 2 files changed, 5 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
> > > index 6e4c744..61bc570 100644
> > > --- a/fs/xfs/xfs_refcount_item.c
> > > +++ b/fs/xfs/xfs_refcount_item.c
> > > @@ -205,7 +205,7 @@ xfs_cui_init(
> > > cuip->cui_format.cui_nextents = nextents;
> > > cuip->cui_format.cui_id = (uintptr_t)(void *)cuip;
> > > atomic_set(&cuip->cui_next_extent, 0);
> > > - atomic_set(&cuip->cui_refcount, 2);
> > > + refcount_set(&cuip->cui_refcount, 2);
> >
> > I'm assuming the refcount design is ok with the log item refcounts
> > starting at 2 and marching down to zero? The code seems to be
> > fine with it; I just want to make sure everyone's ok with supporting
> > this use case.
>
> Yes, as soon as it doesn't go beyond 0 or starting to increment again after reaching zero.
Ok, good.
> >
> > > return cuip;
> > > }
> > > @@ -221,7 +221,7 @@ void
> > > xfs_cui_release(
> > > struct xfs_cui_log_item *cuip)
> > > {
> > > - if (atomic_dec_and_test(&cuip->cui_refcount)) {
> > > + if (refcount_dec_and_test(&cuip->cui_refcount)) {
> >
> > I suppose it's useful to have refcount_dec_and_test complain loudly if
> > we ever have a dangling pointer... Friday I was chasing a possible
> > use-after-free of the EFI items in generic/388.
>
> Currently it complains with WARN if it finds itself decrementing from zero.
> There is patch in RFC stage also that would make it configurable: complain with WARN or complain/abort with BUG.
>
> >
> > > xfs_trans_ail_remove(&cuip->cui_item,
> > SHUTDOWN_LOG_IO_ERROR);
> > > xfs_cui_item_free(cuip);
> > > }
> > > diff --git a/fs/xfs/xfs_refcount_item.h b/fs/xfs/xfs_refcount_item.h
> > > index 5b74ddd..7f23ff8 100644
> > > --- a/fs/xfs/xfs_refcount_item.h
> > > +++ b/fs/xfs/xfs_refcount_item.h
> > > @@ -20,6 +20,8 @@
> > > #ifndef __XFS_REFCOUNT_ITEM_H__
> > > #define __XFS_REFCOUNT_ITEM_H__
> > >
> > > +#include <linux/refcount.h>
> >
> > I still think this include should go in xfs_linux.h, the same as most of
> > the other linux/*.h includes in XFS.
>
> Oh, very sorry, I forgot this one. Got too much focused on testing :(
> Do you want me to resend with this change or can you take it in and do this small fix yourself?
Since the comment applies to all the patches, please resend the series
with all the patches fixed up.
--D
>
> Best Regards,
> Elena.
>
>
> >
> > --D
> >
> > > +
> > > /*
> > > * There are (currently) two pairs of refcount btree redo item types:
> > > * increase and decrease. The log items for these are CUI (refcount
> > > @@ -63,7 +65,7 @@ struct kmem_zone;
> > > */
> > > struct xfs_cui_log_item {
> > > struct xfs_log_item cui_item;
> > > - atomic_t cui_refcount;
> > > + refcount_t cui_refcount;
> > > atomic_t cui_next_extent;
> > > unsigned long cui_flags; /* misc
> > flags */
> > > struct xfs_cui_log_format cui_format;
> > > --
> > > 2.7.4
> > >
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t
2017-11-29 11:37 [PATCH 0/5] v2 xfs refcount conversions Elena Reshetova
@ 2017-11-29 11:37 ` Elena Reshetova
0 siblings, 0 replies; 12+ messages in thread
From: Elena Reshetova @ 2017-11-29 11:37 UTC (permalink / raw)
To: david
Cc: darrick.wong, linux-kernel, linux-xfs, peterz, keescook, Elena Reshetova
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable xfs_bui_log_item.bui_refcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
**Important note for maintainers:
Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts.
The full comparison can be seen in
https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon
in state to be merged to the documentation tree.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.
For the xfs_bui_log_item.bui_refcount it might make a difference
in following places:
- xfs_bui_release(): decrement in refcount_dec_and_test() only
provides RELEASE ordering and control dependency on success
vs. fully ordered atomic counterpart
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
---
fs/xfs/xfs_bmap_item.c | 6 +++---
fs/xfs/xfs_bmap_item.h | 2 +-
fs/xfs/xfs_linux.h | 1 +
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index dd136f7..0f2e3d8 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -201,7 +201,7 @@ xfs_bui_init(
buip->bui_format.bui_nextents = XFS_BUI_MAX_FAST_EXTENTS;
buip->bui_format.bui_id = (uintptr_t)(void *)buip;
atomic_set(&buip->bui_next_extent, 0);
- atomic_set(&buip->bui_refcount, 2);
+ refcount_set(&buip->bui_refcount, 2);
return buip;
}
@@ -217,8 +217,8 @@ void
xfs_bui_release(
struct xfs_bui_log_item *buip)
{
- ASSERT(atomic_read(&buip->bui_refcount) > 0);
- if (atomic_dec_and_test(&buip->bui_refcount)) {
+ ASSERT(refcount_read(&buip->bui_refcount) > 0);
+ if (refcount_dec_and_test(&buip->bui_refcount)) {
xfs_trans_ail_remove(&buip->bui_item, SHUTDOWN_LOG_IO_ERROR);
xfs_bui_item_free(buip);
}
diff --git a/fs/xfs/xfs_bmap_item.h b/fs/xfs/xfs_bmap_item.h
index c867daa..7048b14 100644
--- a/fs/xfs/xfs_bmap_item.h
+++ b/fs/xfs/xfs_bmap_item.h
@@ -61,7 +61,7 @@ struct kmem_zone;
*/
struct xfs_bui_log_item {
struct xfs_log_item bui_item;
- atomic_t bui_refcount;
+ refcount_t bui_refcount;
atomic_t bui_next_extent;
unsigned long bui_flags; /* misc flags */
struct xfs_bui_log_format bui_format;
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index 99562ec..31658ac 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -20,6 +20,7 @@
#include <linux/types.h>
#include <linux/uuid.h>
+#include <linux/refcount.h>
/*
* Kernel specific type declarations for XFS
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t
2017-10-20 11:07 [PATCH 0/5] xfs refcount conversions Elena Reshetova
@ 2017-10-20 11:07 ` Elena Reshetova
0 siblings, 0 replies; 12+ messages in thread
From: Elena Reshetova @ 2017-10-20 11:07 UTC (permalink / raw)
To: darrick.wong; +Cc: linux-kernel, linux-xfs, peterz, keescook, Elena Reshetova
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable xfs_bui_log_item.bui_refcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
---
fs/xfs/xfs_bmap_item.c | 6 +++---
fs/xfs/xfs_bmap_item.h | 2 +-
fs/xfs/xfs_linux.h | 1 +
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index dd136f7..0f2e3d8 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -201,7 +201,7 @@ xfs_bui_init(
buip->bui_format.bui_nextents = XFS_BUI_MAX_FAST_EXTENTS;
buip->bui_format.bui_id = (uintptr_t)(void *)buip;
atomic_set(&buip->bui_next_extent, 0);
- atomic_set(&buip->bui_refcount, 2);
+ refcount_set(&buip->bui_refcount, 2);
return buip;
}
@@ -217,8 +217,8 @@ void
xfs_bui_release(
struct xfs_bui_log_item *buip)
{
- ASSERT(atomic_read(&buip->bui_refcount) > 0);
- if (atomic_dec_and_test(&buip->bui_refcount)) {
+ ASSERT(refcount_read(&buip->bui_refcount) > 0);
+ if (refcount_dec_and_test(&buip->bui_refcount)) {
xfs_trans_ail_remove(&buip->bui_item, SHUTDOWN_LOG_IO_ERROR);
xfs_bui_item_free(buip);
}
diff --git a/fs/xfs/xfs_bmap_item.h b/fs/xfs/xfs_bmap_item.h
index c867daa..7048b14 100644
--- a/fs/xfs/xfs_bmap_item.h
+++ b/fs/xfs/xfs_bmap_item.h
@@ -61,7 +61,7 @@ struct kmem_zone;
*/
struct xfs_bui_log_item {
struct xfs_log_item bui_item;
- atomic_t bui_refcount;
+ refcount_t bui_refcount;
atomic_t bui_next_extent;
unsigned long bui_flags; /* misc flags */
struct xfs_bui_log_format bui_format;
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index dcd1292..0def85f 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -20,6 +20,7 @@
#include <linux/types.h>
#include <linux/uuid.h>
+#include <linux/refcount.h>
/*
* Kernel specific type declarations for XFS
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t
2017-03-08 8:53 [PATCH 0/5] fs, xfs refcount conversions Elena Reshetova
@ 2017-03-08 8:53 ` Elena Reshetova
0 siblings, 0 replies; 12+ messages in thread
From: Elena Reshetova @ 2017-03-08 8:53 UTC (permalink / raw)
To: darrick.wong
Cc: linux-kernel, linux-xfs, Elena Reshetova, Hans Liljestrand,
Kees Cook, David Windsor
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>
---
fs/xfs/xfs_bmap_item.c | 4 ++--
fs/xfs/xfs_bmap_item.h | 2 +-
fs/xfs/xfs_linux.h | 1 +
3 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 9bf57c7..33104ad 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -199,7 +199,7 @@ xfs_bui_init(
buip->bui_format.bui_nextents = XFS_BUI_MAX_FAST_EXTENTS;
buip->bui_format.bui_id = (uintptr_t)(void *)buip;
atomic_set(&buip->bui_next_extent, 0);
- atomic_set(&buip->bui_refcount, 2);
+ refcount_set(&buip->bui_refcount, 2);
return buip;
}
@@ -215,7 +215,7 @@ void
xfs_bui_release(
struct xfs_bui_log_item *buip)
{
- if (atomic_dec_and_test(&buip->bui_refcount)) {
+ if (refcount_dec_and_test(&buip->bui_refcount)) {
xfs_trans_ail_remove(&buip->bui_item, SHUTDOWN_LOG_IO_ERROR);
xfs_bui_item_free(buip);
}
diff --git a/fs/xfs/xfs_bmap_item.h b/fs/xfs/xfs_bmap_item.h
index c867daa..7048b14 100644
--- a/fs/xfs/xfs_bmap_item.h
+++ b/fs/xfs/xfs_bmap_item.h
@@ -61,7 +61,7 @@ struct kmem_zone;
*/
struct xfs_bui_log_item {
struct xfs_log_item bui_item;
- atomic_t bui_refcount;
+ refcount_t bui_refcount;
atomic_t bui_next_extent;
unsigned long bui_flags; /* misc flags */
struct xfs_bui_log_format bui_format;
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index 7a989de..09b0396 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -19,6 +19,7 @@
#define __XFS_LINUX__
#include <linux/types.h>
+#include <linux/refcount.h>
/*
* Kernel specific type declarations for XFS
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
end of thread, other threads:[~2017-11-29 11:38 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-03-01 8:47 [PATCH 0/5] fs, xfs atomic_t to refcount_t conversions version 2 Elena Reshetova
2017-03-01 8:47 ` [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t Elena Reshetova
2017-03-01 8:47 ` [PATCH 2/5] fs, xfs: convert xfs_efi_log_item.efi_refcount " Elena Reshetova
2017-03-01 8:47 ` [PATCH 3/5] fs, xfs: convert xlog_ticket.t_ref " Elena Reshetova
2017-03-01 8:47 ` [PATCH 4/5] fs, xfs: convert xfs_cui_log_item.cui_refcount " Elena Reshetova
2017-03-06 19:14 ` Darrick J. Wong
2017-03-07 17:33 ` Reshetova, Elena
2017-03-07 20:30 ` Darrick J. Wong
2017-03-01 8:47 ` [PATCH 5/5] fs, xfs: convert xfs_rui_log_item.rui_refcount " Elena Reshetova
2017-03-08 8:53 [PATCH 0/5] fs, xfs refcount conversions Elena Reshetova
2017-03-08 8:53 ` [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t Elena Reshetova
2017-10-20 11:07 [PATCH 0/5] xfs refcount conversions Elena Reshetova
2017-10-20 11:07 ` [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t Elena Reshetova
2017-11-29 11:37 [PATCH 0/5] v2 xfs refcount conversions Elena Reshetova
2017-11-29 11:37 ` [PATCH 1/5] fs, xfs: convert xfs_bui_log_item.bui_refcount from atomic_t to refcount_t Elena Reshetova
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