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* Re: [PATCH] padata: Convert from atomic_t to refcount_t on parallel_data->refcnt
       [not found] <1626683853-64734-1-git-send-email-xiyuyang19@fudan.edu.cn>
@ 2021-07-19 21:46 ` Daniel Jordan
  2021-07-20 15:05   ` Daniel Jordan
  0 siblings, 1 reply; 3+ messages in thread
From: Daniel Jordan @ 2021-07-19 21:46 UTC (permalink / raw)
  To: Xiyu Yang
  Cc: Steffen Klassert, linux-crypto, linux-kernel, yuanxzhang,
	Xin Tan, Herbert Xu

On Mon, Jul 19, 2021 at 04:37:33PM +0800, Xiyu Yang wrote:
> refcount_t type and corresponding API can protect refcounters from
> accidental underflow and overflow and further use-after-free situations.
> 
> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>

This patch run on a big server didn't turn up anything, but it's
probably useful to have the extra checking.

Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [PATCH] padata: Convert from atomic_t to refcount_t on parallel_data->refcnt
  2021-07-19 21:46 ` [PATCH] padata: Convert from atomic_t to refcount_t on parallel_data->refcnt Daniel Jordan
@ 2021-07-20 15:05   ` Daniel Jordan
  2021-07-30  3:10     ` Herbert Xu
  0 siblings, 1 reply; 3+ messages in thread
From: Daniel Jordan @ 2021-07-20 15:05 UTC (permalink / raw)
  To: Herbert Xu, Steffen Klassert, Daniel Jordan
  Cc: Xiyu Yang, yuanxzhang, Xin Tan, linux-crypto, linux-kernel

From: Xiyu Yang <xiyuyang19@fudan.edu.cn>

refcount_t type and corresponding API can protect refcounters from
accidental underflow and overflow and further use-after-free situations.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>
---

This seems not to have made it to the lists even though they were
originally cc'd.  Reposting.

 include/linux/padata.h | 3 ++-
 kernel/padata.c        | 8 ++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/linux/padata.h b/include/linux/padata.h
index a433f13fc4bf..495b16b6b4d7 100644
--- a/include/linux/padata.h
+++ b/include/linux/padata.h
@@ -12,6 +12,7 @@
 #ifndef PADATA_H
 #define PADATA_H
 
+#include <linux/refcount.h>
 #include <linux/compiler_types.h>
 #include <linux/workqueue.h>
 #include <linux/spinlock.h>
@@ -96,7 +97,7 @@ struct parallel_data {
 	struct padata_shell		*ps;
 	struct padata_list		__percpu *reorder_list;
 	struct padata_serial_queue	__percpu *squeue;
-	atomic_t			refcnt;
+	refcount_t			refcnt;
 	unsigned int			seq_nr;
 	unsigned int			processed;
 	int				cpu;
diff --git a/kernel/padata.c b/kernel/padata.c
index d4d3ba6e1728..378c36080781 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -211,7 +211,7 @@ int padata_do_parallel(struct padata_shell *ps,
 	if ((pinst->flags & PADATA_RESET))
 		goto out;
 
-	atomic_inc(&pd->refcnt);
+	refcount_inc(&pd->refcnt);
 	padata->pd = pd;
 	padata->cb_cpu = *cb_cpu;
 
@@ -383,7 +383,7 @@ static void padata_serial_worker(struct work_struct *serial_work)
 	}
 	local_bh_enable();
 
-	if (atomic_sub_and_test(cnt, &pd->refcnt))
+	if (refcount_sub_and_test(cnt, &pd->refcnt))
 		padata_free_pd(pd);
 }
 
@@ -593,7 +593,7 @@ static struct parallel_data *padata_alloc_pd(struct padata_shell *ps)
 	padata_init_reorder_list(pd);
 	padata_init_squeues(pd);
 	pd->seq_nr = -1;
-	atomic_set(&pd->refcnt, 1);
+	refcount_set(&pd->refcnt, 1);
 	spin_lock_init(&pd->lock);
 	pd->cpu = cpumask_first(pd->cpumask.pcpu);
 	INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
@@ -667,7 +667,7 @@ static int padata_replace(struct padata_instance *pinst)
 	synchronize_rcu();
 
 	list_for_each_entry_continue_reverse(ps, &pinst->pslist, list)
-		if (atomic_dec_and_test(&ps->opd->refcnt))
+		if (refcount_dec_and_test(&ps->opd->refcnt))
 			padata_free_pd(ps->opd);
 
 	pinst->flags &= ~PADATA_RESET;
-- 
2.32.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] padata: Convert from atomic_t to refcount_t on parallel_data->refcnt
  2021-07-20 15:05   ` Daniel Jordan
@ 2021-07-30  3:10     ` Herbert Xu
  0 siblings, 0 replies; 3+ messages in thread
From: Herbert Xu @ 2021-07-30  3:10 UTC (permalink / raw)
  To: Daniel Jordan
  Cc: Steffen Klassert, Xiyu Yang, yuanxzhang, Xin Tan, linux-crypto,
	linux-kernel

On Tue, Jul 20, 2021 at 11:05:11AM -0400, Daniel Jordan wrote:
> From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> 
> refcount_t type and corresponding API can protect refcounters from
> accidental underflow and overflow and further use-after-free situations.
> 
> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
> Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>
> ---
> 
> This seems not to have made it to the lists even though they were
> originally cc'd.  Reposting.
> 
>  include/linux/padata.h | 3 ++-
>  kernel/padata.c        | 8 ++++----
>  2 files changed, 6 insertions(+), 5 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-07-30  3:11 UTC | newest]

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2021-07-19 21:46 ` [PATCH] padata: Convert from atomic_t to refcount_t on parallel_data->refcnt Daniel Jordan
2021-07-20 15:05   ` Daniel Jordan
2021-07-30  3:10     ` Herbert Xu

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