From: Daniel Jordan <daniel.m.jordan@oracle.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sasha Levin <sashal@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>,
Herbert Xu <herbert@gondor.apana.org.au>,
Mathias Krause <minipli@googlemail.com>,
Steffen Klassert <steffen.klassert@secunet.com>,
stable@vger.kernel.org, linux-crypto@vger.kernel.org,
Daniel Jordan <daniel.m.jordan@oracle.com>
Subject: [stable-4.14 3/4] padata: initialize pd->cpu with effective cpumask
Date: Thu, 21 May 2020 16:46:57 -0400 [thread overview]
Message-ID: <20200521204658.1952777-3-daniel.m.jordan@oracle.com> (raw)
In-Reply-To: <20200521204658.1952777-1-daniel.m.jordan@oracle.com>
[ Upstream commit ec9c7d19336ee98ecba8de80128aa405c45feebb ]
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: Daniel Jordan <daniel.m.jordan@oracle.com>
---
kernel/padata.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/padata.c b/kernel/padata.c
index 66d96ed62286..6d0cdee9d321 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -450,7 +450,7 @@ static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
atomic_set(&pd->refcnt, 1);
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;
--
2.26.2
next prev parent reply other threads:[~2020-05-21 20:47 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-21 20:46 [stable-4.14 1/4] padata: set cpu_index of unused CPUs to -1 Daniel Jordan
2020-05-21 20:46 ` [stable-4.14 2/4] padata: Replace delayed timer with immediate workqueue in padata_reorder Daniel Jordan
2020-05-21 20:46 ` Daniel Jordan [this message]
2020-05-21 20:46 ` [stable-4.14 4/4] padata: purge get_cpu and reorder_via_wq from padata_do_serial Daniel Jordan
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