From: Herbert Xu <herbert@gondor.apana.org.au>
To: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>,
andrea.parri@amarulasolutions.com, boqun.feng@gmail.com,
paulmck@linux.ibm.com, peterz@infradead.org,
linux-arch@vger.kernel.org, linux-crypto@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] padata: Use RCU when fetching pd from do_serial
Date: Tue, 16 Jul 2019 20:57:04 +0800 [thread overview]
Message-ID: <20190716125704.l2jolyyd3bue6hhn@gondor.apana.org.au> (raw)
In-Reply-To: <20190716111410.GN17989@gauss3.secunet.de>
On Tue, Jul 16, 2019 at 01:14:10PM +0200, Steffen Klassert wrote:
>
> Maybe we can fix it if we call padata_free_pd() from
> padata_serial_worker() when it sent out the last object.
How about using RCU?
We still need to fix up the refcnt if it's supposed to limit the
overall number of outstanding requests.
---8<---
The function padata_do_serial uses parallel_data without obeying
the RCU rules around its life-cycle. This means that a concurrent
padata_replace call can result in a crash.
This patch fixes it by using RCU just as we do in padata_do_parallel.
Fixes: 16295bec6398 ("padata: Generic parallelization/...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/include/linux/padata.h b/include/linux/padata.h
index 5d13d25da2c8..952f6514dd72 100644
--- a/include/linux/padata.h
+++ b/include/linux/padata.h
@@ -35,7 +35,7 @@
* struct padata_priv - Embedded to the users data structure.
*
* @list: List entry, to attach to the padata lists.
- * @pd: Pointer to the internal control structure.
+ * @inst: Pointer to the overall control structure.
* @cb_cpu: Callback cpu for serializatioon.
* @cpu: Cpu for parallelization.
* @seq_nr: Sequence number of the parallelized data object.
@@ -45,7 +45,7 @@
*/
struct padata_priv {
struct list_head list;
- struct parallel_data *pd;
+ struct padata_instance *inst;
int cb_cpu;
int cpu;
int info;
diff --git a/kernel/padata.c b/kernel/padata.c
index 2d2fddbb7a4c..fb5dd1210d2b 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -128,7 +128,7 @@ int padata_do_parallel(struct padata_instance *pinst,
err = 0;
atomic_inc(&pd->refcnt);
- padata->pd = pd;
+ padata->inst = pinst;
padata->cb_cpu = cb_cpu;
target_cpu = padata_cpu_hash(pd);
@@ -367,7 +368,7 @@ void padata_do_serial(struct padata_priv *padata)
struct parallel_data *pd;
int reorder_via_wq = 0;
- pd = padata->pd;
+ pd = rcu_dereference_bh(padata->inst->pd);
cpu = get_cpu();
--
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
next prev parent reply other threads:[~2019-07-16 12:57 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-11 22:12 [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Daniel Jordan
2019-07-12 10:06 ` Herbert Xu
2019-07-12 10:10 ` Steffen Klassert
2019-07-12 16:07 ` Daniel Jordan
2019-07-13 5:03 ` Herbert Xu
2019-07-15 16:10 ` Daniel Jordan
2019-07-16 10:04 ` Herbert Xu
2019-07-16 11:14 ` Steffen Klassert
2019-07-16 12:57 ` Herbert Xu [this message]
2019-07-16 13:09 ` [PATCH] padata: Use RCU when fetching pd from do_serial Herbert Xu
2019-07-16 13:23 ` [v2 PATCH] " Herbert Xu
2019-07-17 8:36 ` Steffen Klassert
2019-07-17 8:50 ` Herbert Xu
2019-07-17 8:28 ` [PATCH] " Steffen Klassert
2019-07-17 8:47 ` Herbert Xu
2019-07-17 8:53 ` Steffen Klassert
2019-07-16 13:15 ` Peter Zijlstra
2019-07-16 13:18 ` Herbert Xu
2019-07-16 13:50 ` Peter Zijlstra
2019-07-16 13:52 ` Herbert Xu
2019-07-16 12:53 ` [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Andrea Parri
2019-07-16 13:13 ` Peter Zijlstra
2019-07-16 15:01 ` Herbert Xu
2019-07-16 15:44 ` Daniel Jordan
2019-07-16 16:32 ` [PATCH v2] " Daniel Jordan
2019-07-17 11:11 ` [PATCH] padata: Replace delayed timer with immediate workqueue in padata_reorder Herbert Xu
2019-07-17 18:32 ` Daniel Jordan
2019-07-18 3:31 ` Herbert Xu
2019-07-18 14:27 ` Daniel Jordan
2019-07-18 14:56 ` Herbert Xu
2019-07-18 15:01 ` [v2 PATCH] " Herbert Xu
2019-07-19 14:37 ` Daniel Jordan
2019-07-19 14:55 ` Herbert Xu
2019-07-19 19:04 ` [PATCH] padata: purge get_cpu and reorder_via_wq from padata_do_serial Daniel Jordan
2019-07-26 12:36 ` Herbert Xu
2019-07-19 14:27 ` [PATCH] padata: Replace delayed timer with immediate workqueue in padata_reorder Daniel Jordan
2019-07-17 23:21 ` Daniel Jordan
2019-07-18 3:30 ` Herbert Xu
2019-07-18 14:25 ` Daniel Jordan
2019-07-18 14:49 ` Herbert Xu
2019-07-19 14:21 ` Daniel Jordan
2019-07-18 5:42 ` [PATCH v2] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Herbert Xu
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