We found a hungtask bug in test_aead_vec_cfg as follows:
INFO: task cryptomgr_test:391009 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Call trace:
__switch_to+0x98/0xe0
__schedule+0x6c4/0xf40
schedule+0xd8/0x1b4
schedule_timeout+0x474/0x560
wait_for_common+0x368/0x4e0
wait_for_completion+0x20/0x30
test_aead_vec_cfg+0xab4/0xd50
test_aead+0x144/0x1f0
alg_test_aead+0xd8/0x1e0
alg_test+0x634/0x890
cryptomgr_test+0x40/0x70
kthread+0x1e0/0x220
ret_from_fork+0x10/0x18
Kernel panic - not syncing: hung_task: blocked tasks
For padata_do_parallel, when the return err is 0 or -EBUSY, it will call
wait_for_completion(&wait->completion) in test_aead_vec_cfg. In normal
case, aead_request_complete() will be called in pcrypt_aead_serial and the
return err is 0 for padata_do_parallel. But, when pinst->flags is
PADATA_RESET, the return err is -EBUSY for padata_do_parallel, and it
won't call aead_request_complete(). Therefore, test_aead_vec_cfg will
hung at wait_for_completion(&wait->completion), which will cause
hungtask.
The problem comes as following:
(padata_do_parallel) |
rcu_read_lock_bh(); |
err = -EINVAL; | (padata_replace)
| pinst->flags |= PADATA_RESET;
err = -EBUSY |
if (pinst->flags & PADATA_RESET) |
rcu_read_unlock_bh() |
return err
In order to resolve the problem, we retry at most 5 times when
padata_do_parallel return -EBUSY. For more than 5 times, we replace the
return err -EBUSY with -EAGAIN, which means parallel_data is changing, and
the caller should call it again.
v2:
introduce padata_try_do_parallel() in pcrypt_aead_encrypt and
pcrypt_aead_decrypt to solve the hungtask
Signed-off-by: Lu Jialin <lujialin4@xxxxxxxxxx>
Signed-off-by: Guo Zihua <guozihua@xxxxxxxxxx>
---
crypto/pcrypt.c | 33 +++++++++++++++++++++++++++------
kernel/padata.c | 2 +-
2 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
index 8c1d0ca41213..9d4470482165 100644
--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -74,6 +74,31 @@ static void pcrypt_aead_done(void *data, int err)
padata_do_serial(padata);
}
+/*
+ * We retry at most 5 times when padata_do_parallel return -EBUSY.
+ * For more than 5 times, we replace the return err -EBUSY with -EAGAIN,
+ * which means parallel_data is changing, the caller should call it again.
+ */
+static int padata_try_do_paralell(struct padata_shell *ps,
+ struct padata_priv *padata, int *cb_cpu)
+{
+ int err = 0;
+ int nr_retries = 5;
+
+ while (nr_retries--) {
+ err = padata_do_parallel(ps, padata, cb_cpu);
+ if (err != -EBUSY)
+ break;
+ }
+
+ if (err == 0)
+ err = -EINPROGRESS;
+ else if (err == -EBUSY)
+ err = -EAGAIN;
+
+ return err;
+}
+
static void pcrypt_aead_enc(struct padata_priv *padata)
{
struct pcrypt_request *preq = pcrypt_padata_request(padata);
@@ -114,9 +139,7 @@ static int pcrypt_aead_encrypt(struct aead_request *req)
req->cryptlen, req->iv);
aead_request_set_ad(creq, req->assoclen);
- err = padata_do_parallel(ictx->psenc, padata, &ctx->cb_cpu);
- if (!err)
- return -EINPROGRESS;
+ err = padata_try_do_paralell(ictx->psenc, padata, &ctx->cb_cpu);
return err;
}
@@ -161,9 +184,7 @@ static int pcrypt_aead_decrypt(struct aead_request *req)
req->cryptlen, req->iv);
aead_request_set_ad(creq, req->assoclen);
- err = padata_do_parallel(ictx->psdec, padata, &ctx->cb_cpu);
- if (!err)
- return -EINPROGRESS;
+ err = padata_try_do_paralell(ictx->psenc, padata, &ctx->cb_cpu);
return err;
}
diff --git a/kernel/padata.c b/kernel/padata.c
index 222d60195de6..81c8183f3176 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -202,7 +202,7 @@ int padata_do_parallel(struct padata_shell *ps,
*cb_cpu = cpu;
}
- err = -EBUSY;
+ err = -EBUSY;
if ((pinst->flags & PADATA_RESET))
goto out;
--
2.34.1
