| Message ID | 20230904133341.2528440-1-lujialin4@huawei.com |
|---|---|
| State | Accepted |
| Commit | 8f4f68e788c3a7a696546291258bfa5fdb215523 |
| Headers | show |
| Series | [v3] crypto: Fix hungtask for PADATA_RESET | expand |
Hi Steffen, padata_do_parallel is only called by pcrypt_aead_encrypt/decrypt, therefore, changing in padata_do_parallel and changing in pcrypt_aead_encrypt/decrypt have the same effect. Both should be ok. Thanks. Herbert, the two ways look both right. What is your suggestion? On 2023/9/5 17:45, Steffen Klassert wrote: > On Mon, Sep 04, 2023 at 01:33:41PM +0000, Lu Jialin wrote: >> --- >> 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 8c1d0ca41213..d0d954fe9d54 100644 >> --- a/crypto/pcrypt.c >> +++ b/crypto/pcrypt.c >> @@ -117,6 +117,8 @@ static int pcrypt_aead_encrypt(struct aead_request *req) >> err = padata_do_parallel(ictx->psenc, padata, &ctx->cb_cpu); >> if (!err) >> return -EINPROGRESS; >> + if (err == -EBUSY) >> + return -EAGAIN; >> >> return err; >> } >> @@ -164,6 +166,8 @@ static int pcrypt_aead_decrypt(struct aead_request *req) >> err = padata_do_parallel(ictx->psdec, padata, &ctx->cb_cpu); >> if (!err) >> return -EINPROGRESS; >> + if (err == -EBUSY) >> + return -EAGAIN; >> >> 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; > Why not just returning -EAGAIN here directly? > >
On Wed, Sep 06, 2023 at 03:49:30PM +0800, Lu Jialin wrote: > Hi Steffen, > > padata_do_parallel is only called by pcrypt_aead_encrypt/decrypt, therefore, > changing in padata_do_parallel and changing in pcrypt_aead_encrypt/decrypt > have the same effect. Both should be ok. > > Thanks. > > Herbert, the two ways look both right. What is your suggestion? Either way is fine by me. Thanks,
On Mon, Sep 04, 2023 at 01:33:41PM +0000, Lu Jialin wrote: > 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 > 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 replace the return err -EBUSY with > -EAGAIN, which means parallel_data is changing, and the caller should call > it again. > > v3: > remove retry and just change the return err. > v2: > introduce padata_try_do_parallel() in pcrypt_aead_encrypt and > pcrypt_aead_decrypt to solve the hungtask. > > Signed-off-by: Lu Jialin <lujialin4@huawei.com> > Signed-off-by: Guo Zihua <guozihua@huawei.com> > --- > crypto/pcrypt.c | 4 ++++ > kernel/padata.c | 2 +- > 2 files changed, 5 insertions(+), 1 deletion(-) Patch applied. Thanks.
diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c index 8c1d0ca41213..d0d954fe9d54 100644 --- a/crypto/pcrypt.c +++ b/crypto/pcrypt.c @@ -117,6 +117,8 @@ static int pcrypt_aead_encrypt(struct aead_request *req) err = padata_do_parallel(ictx->psenc, padata, &ctx->cb_cpu); if (!err) return -EINPROGRESS; + if (err == -EBUSY) + return -EAGAIN; return err; } @@ -164,6 +166,8 @@ static int pcrypt_aead_decrypt(struct aead_request *req) err = padata_do_parallel(ictx->psdec, padata, &ctx->cb_cpu); if (!err) return -EINPROGRESS; + if (err == -EBUSY) + return -EAGAIN; 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;
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 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 replace the return err -EBUSY with -EAGAIN, which means parallel_data is changing, and the caller should call it again. v3: remove retry and just change the return err. v2: introduce padata_try_do_parallel() in pcrypt_aead_encrypt and pcrypt_aead_decrypt to solve the hungtask. Signed-off-by: Lu Jialin <lujialin4@huawei.com> Signed-off-by: Guo Zihua <guozihua@huawei.com> --- crypto/pcrypt.c | 4 ++++ kernel/padata.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-)