* [PATCH 3.16 10/99] padata: initialize pd->cpu with effective cpumask
[not found] <lsq.1589984008.673931885@decadent.org.uk>
@ 2020-05-20 14:13 ` Ben Hutchings
2020-05-20 14:13 ` [PATCH 3.16 12/99] padata: purge get_cpu and reorder_via_wq from padata_do_serial Ben Hutchings
2020-05-20 14:13 ` [PATCH 3.16 15/99] padata: always acquire cpu_hotplug_lock before pinst->lock Ben Hutchings
2 siblings, 0 replies; 3+ messages in thread
From: Ben Hutchings @ 2020-05-20 14:13 UTC (permalink / raw)
To: linux-kernel, stable
Cc: akpm, Denis Kirjanov, Steffen Klassert, linux-crypto, Herbert Xu,
Daniel Jordan
3.16.84-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Daniel Jordan <daniel.m.jordan@oracle.com>
commit ec9c7d19336ee98ecba8de80128aa405c45feebb upstream.
Exercising CPU hotplug on a 5.2 kernel with recent padata fixes from
cryptodev-2.6.git in an 8-CPU kvm guest...
# modprobe tcrypt alg="pcrypt(rfc4106(gcm(aes)))" type=3
# echo 0 > /sys/devices/system/cpu/cpu1/online
# echo c > /sys/kernel/pcrypt/pencrypt/parallel_cpumask
# modprobe tcrypt mode=215
...caused the following crash:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 2 PID: 134 Comm: kworker/2:2 Not tainted 5.2.0-padata-base+ #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-<snip>
Workqueue: pencrypt padata_parallel_worker
RIP: 0010:padata_reorder+0xcb/0x180
...
Call Trace:
padata_do_serial+0x57/0x60
pcrypt_aead_enc+0x3a/0x50 [pcrypt]
padata_parallel_worker+0x9b/0xe0
process_one_work+0x1b5/0x3f0
worker_thread+0x4a/0x3c0
...
In padata_alloc_pd, pd->cpu is set using the user-supplied cpumask
instead of the effective cpumask, and in this case cpumask_first picked
an offline CPU.
The offline CPU's reorder->list.next is NULL in padata_reorder because
the list wasn't initialized in padata_init_pqueues, which only operates
on CPUs in the effective mask.
Fix by using the effective mask in padata_alloc_pd.
Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
kernel/padata.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -435,7 +435,7 @@ static struct parallel_data *padata_allo
atomic_set(&pd->refcnt, 0);
pd->pinst = pinst;
spin_lock_init(&pd->lock);
- pd->cpu = cpumask_first(pcpumask);
+ pd->cpu = cpumask_first(pd->cpumask.pcpu);
INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
return pd;
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 3.16 12/99] padata: purge get_cpu and reorder_via_wq from padata_do_serial
[not found] <lsq.1589984008.673931885@decadent.org.uk>
2020-05-20 14:13 ` [PATCH 3.16 10/99] padata: initialize pd->cpu with effective cpumask Ben Hutchings
@ 2020-05-20 14:13 ` Ben Hutchings
2020-05-20 14:13 ` [PATCH 3.16 15/99] padata: always acquire cpu_hotplug_lock before pinst->lock Ben Hutchings
2 siblings, 0 replies; 3+ messages in thread
From: Ben Hutchings @ 2020-05-20 14:13 UTC (permalink / raw)
To: linux-kernel, stable
Cc: akpm, Denis Kirjanov, Steffen Klassert, linux-crypto, Herbert Xu,
Daniel Jordan
3.16.84-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Daniel Jordan <daniel.m.jordan@oracle.com>
commit 065cf577135a4977931c7a1e1edf442bfd9773dd upstream.
With the removal of the padata timer, padata_do_serial no longer
needs special CPU handling, so remove it.
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
kernel/padata.c | 23 +++--------------------
1 file changed, 3 insertions(+), 20 deletions(-)
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -322,24 +322,9 @@ static void padata_serial_worker(struct
*/
void padata_do_serial(struct padata_priv *padata)
{
- int cpu;
- struct padata_parallel_queue *pqueue;
- struct parallel_data *pd;
- int reorder_via_wq = 0;
-
- pd = padata->pd;
-
- cpu = get_cpu();
-
- /* We need to enqueue the padata object into the correct
- * per-cpu queue.
- */
- if (cpu != padata->cpu) {
- reorder_via_wq = 1;
- cpu = padata->cpu;
- }
-
- pqueue = per_cpu_ptr(pd->pqueue, cpu);
+ struct parallel_data *pd = padata->pd;
+ struct padata_parallel_queue *pqueue = per_cpu_ptr(pd->pqueue,
+ padata->cpu);
spin_lock(&pqueue->reorder.lock);
list_add_tail(&padata->list, &pqueue->reorder.list);
@@ -353,8 +338,6 @@ void padata_do_serial(struct padata_priv
*/
smp_mb__after_atomic();
- put_cpu();
-
padata_reorder(pd);
}
EXPORT_SYMBOL(padata_do_serial);
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 3.16 15/99] padata: always acquire cpu_hotplug_lock before pinst->lock
[not found] <lsq.1589984008.673931885@decadent.org.uk>
2020-05-20 14:13 ` [PATCH 3.16 10/99] padata: initialize pd->cpu with effective cpumask Ben Hutchings
2020-05-20 14:13 ` [PATCH 3.16 12/99] padata: purge get_cpu and reorder_via_wq from padata_do_serial Ben Hutchings
@ 2020-05-20 14:13 ` Ben Hutchings
2 siblings, 0 replies; 3+ messages in thread
From: Ben Hutchings @ 2020-05-20 14:13 UTC (permalink / raw)
To: linux-kernel, stable
Cc: akpm, Denis Kirjanov, Steffen Klassert, Eric Biggers,
linux-crypto, Herbert Xu, Daniel Jordan
3.16.84-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Daniel Jordan <daniel.m.jordan@oracle.com>
commit 38228e8848cd7dd86ccb90406af32de0cad24be3 upstream.
lockdep complains when padata's paths to update cpumasks via CPU hotplug
and sysfs are both taken:
# echo 0 > /sys/devices/system/cpu/cpu1/online
# echo ff > /sys/kernel/pcrypt/pencrypt/parallel_cpumask
======================================================
WARNING: possible circular locking dependency detected
5.4.0-rc8-padata-cpuhp-v3+ #1 Not tainted
------------------------------------------------------
bash/205 is trying to acquire lock:
ffffffff8286bcd0 (cpu_hotplug_lock.rw_sem){++++}, at: padata_set_cpumask+0x2b/0x120
but task is already holding lock:
ffff8880001abfa0 (&pinst->lock){+.+.}, at: padata_set_cpumask+0x26/0x120
which lock already depends on the new lock.
padata doesn't take cpu_hotplug_lock and pinst->lock in a consistent
order. Which should be first? CPU hotplug calls into padata with
cpu_hotplug_lock already held, so it should have priority.
Fixes: 6751fb3c0e0c ("padata: Use get_online_cpus/put_online_cpus")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
kernel/padata.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -614,8 +614,8 @@ int padata_set_cpumask(struct padata_ins
struct cpumask *serial_mask, *parallel_mask;
int err = -EINVAL;
- mutex_lock(&pinst->lock);
get_online_cpus();
+ mutex_lock(&pinst->lock);
switch (cpumask_type) {
case PADATA_CPU_PARALLEL:
@@ -633,8 +633,8 @@ int padata_set_cpumask(struct padata_ins
err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
out:
- put_online_cpus();
mutex_unlock(&pinst->lock);
+ put_online_cpus();
return err;
}
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-05-20 14:28 UTC | newest]
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[not found] <lsq.1589984008.673931885@decadent.org.uk>
2020-05-20 14:13 ` [PATCH 3.16 10/99] padata: initialize pd->cpu with effective cpumask Ben Hutchings
2020-05-20 14:13 ` [PATCH 3.16 12/99] padata: purge get_cpu and reorder_via_wq from padata_do_serial Ben Hutchings
2020-05-20 14:13 ` [PATCH 3.16 15/99] padata: always acquire cpu_hotplug_lock before pinst->lock Ben Hutchings
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