hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I7Y2IE CVE: NA

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We found a hungtask bug in test_aead_vec_cfg as follows:

[ 2297.136299] INFO: task cryptomgr_test:391009 blocked for more than 120 seconds. [ 2297.157611] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2297.168592] task:cryptomgr_test state:D stack: 0 pid:391009 ppid: 2 flags:0x00000208 [ 2297.168611] Call trace: [ 2297.193085] __switch_to+0x98/0xe0 [ 2297.199815] __schedule+0x6c4/0xf40 [ 2297.206674] schedule+0xd8/0x1b4 [ 2297.213223] schedule_timeout+0x474/0x560 [ 2297.220594] wait_for_common+0x368/0x4e0 [ 2297.227929] wait_for_completion+0x20/0x30 [ 2297.235480] test_aead_vec_cfg+0xab4/0xd50 [ 2297.243045] test_aead+0x144/0x1f0 [ 2297.249986] alg_test_aead+0xd8/0x1e0 [ 2297.257148] alg_test+0x634/0x890 [ 2297.264013] cryptomgr_test+0x40/0x70 [ 2297.271243] kthread+0x1e0/0x220 [ 2297.278070] ret_from_fork+0x10/0x18 [ 2297.285503] 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, change the return err to -EAGAIN when pinst->flags is set PADATA_RESET.

Signed-off-by: Lu Jialin lujialin4@huawei.com --- crypto/pcrypt.c | 4 ++++ kernel/padata.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c index 4bf4bb5b1a8b..ebe1f3639a22 100644 --- a/crypto/pcrypt.c +++ b/crypto/pcrypt.c @@ -175,6 +175,8 @@ static int pcrypt_aead_encrypt(struct aead_request *req) err = pcrypt_do_parallel(padata, &ctx->cb_cpu, &pencrypt); if (!err) return -EINPROGRESS; + if (err == -EBUSY) + return -EAGAIN;

return err; } @@ -219,6 +221,8 @@ static int pcrypt_aead_decrypt(struct aead_request *req) err = pcrypt_do_parallel(padata, &ctx->cb_cpu, &pdecrypt); if (!err) return -EINPROGRESS; + if (err == -EBUSY) + return -EAGAIN;

return err; } diff --git a/kernel/padata.c b/kernel/padata.c index 93e4fb2d9f2e..848e40e3581b 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -121,7 +121,7 @@ int padata_do_parallel(struct padata_instance *pinst, if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu)) goto out;

- err = -EBUSY; + err = -EBUSY; if ((pinst->flags & PADATA_RESET)) goto out;