* [PATCH] lightnvm: pblk: Fix two sleep-in-atomic-context bugs in pblk_line_submit_smeta_io()
@ 2018-09-01 11:53 Jia-Ju Bai
2018-09-04 10:11 ` Matias Bjørling
0 siblings, 1 reply; 4+ messages in thread
From: Jia-Ju Bai @ 2018-09-01 11:53 UTC (permalink / raw)
To: mb; +Cc: linux-block, linux-kernel, Jia-Ju Bai
The driver may sleep with holding a spinlock.
The function call paths (from bottom to top) in Linux-4.16 are:
[FUNC] nvm_dev_dma_alloc(GFP_KERNEL)
drivers/lightnvm/pblk-core.c, 754:
nvm_dev_dma_alloc in pblk_line_submit_smeta_io
drivers/lightnvm/pblk-core.c, 1048:
pblk_line_submit_smeta_io in pblk_line_init_bb
drivers/lightnvm/pblk-core.c, 1434:
pblk_line_init_bb in pblk_line_replace_data
drivers/lightnvm/pblk-recovery.c, 980:
pblk_line_replace_data in pblk_recov_l2p
drivers/lightnvm/pblk-recovery.c, 976:
spin_lock in pblk_recov_l2p
[FUNC] bio_map_kern(GFP_KERNEL)
drivers/lightnvm/pblk-core.c, 762:
bio_map_kern in pblk_line_submit_smeta_io
drivers/lightnvm/pblk-core.c, 1048:
pblk_line_submit_smeta_io in pblk_line_init_bb
drivers/lightnvm/pblk-core.c, 1434:
pblk_line_init_bb in pblk_line_replace_data
drivers/lightnvm/pblk-recovery.c, 980:
pblk_line_replace_data in pblk_recov_l2p
drivers/lightnvm/pblk-recovery.c, 976:
spin_lock in pblk_recov_l2p
To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC.
These bugs are found by my static analysis tool DSAC.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
drivers/lightnvm/pblk-core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index ed9cc977c8b3..5d915c93b6cf 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -802,7 +802,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
memset(&rqd, 0, sizeof(struct nvm_rq));
- rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+ rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_ATOMIC,
&rqd.dma_meta_list);
if (!rqd.meta_list)
return -ENOMEM;
@@ -810,7 +810,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size;
rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size;
- bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_KERNEL);
+ bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_ATOMIC);
if (IS_ERR(bio)) {
ret = PTR_ERR(bio);
goto free_ppa_list;
--
2.17.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] lightnvm: pblk: Fix two sleep-in-atomic-context bugs in pblk_line_submit_smeta_io()
2018-09-01 11:53 [PATCH] lightnvm: pblk: Fix two sleep-in-atomic-context bugs in pblk_line_submit_smeta_io() Jia-Ju Bai
@ 2018-09-04 10:11 ` Matias Bjørling
2018-09-04 17:52 ` Javier Gonzalez
0 siblings, 1 reply; 4+ messages in thread
From: Matias Bjørling @ 2018-09-04 10:11 UTC (permalink / raw)
To: baijiaju1990; +Cc: linux-block, linux-kernel, javier, hans.holmberg
On 09/01/2018 01:53 PM, Jia-Ju Bai wrote:
> The driver may sleep with holding a spinlock.
>
> The function call paths (from bottom to top) in Linux-4.16 are:
>
> [FUNC] nvm_dev_dma_alloc(GFP_KERNEL)
> drivers/lightnvm/pblk-core.c, 754:
> nvm_dev_dma_alloc in pblk_line_submit_smeta_io
> drivers/lightnvm/pblk-core.c, 1048:
> pblk_line_submit_smeta_io in pblk_line_init_bb
> drivers/lightnvm/pblk-core.c, 1434:
> pblk_line_init_bb in pblk_line_replace_data
> drivers/lightnvm/pblk-recovery.c, 980:
> pblk_line_replace_data in pblk_recov_l2p
> drivers/lightnvm/pblk-recovery.c, 976:
> spin_lock in pblk_recov_l2p
>
> [FUNC] bio_map_kern(GFP_KERNEL)
> drivers/lightnvm/pblk-core.c, 762:
> bio_map_kern in pblk_line_submit_smeta_io
> drivers/lightnvm/pblk-core.c, 1048:
> pblk_line_submit_smeta_io in pblk_line_init_bb
> drivers/lightnvm/pblk-core.c, 1434:
> pblk_line_init_bb in pblk_line_replace_data
> drivers/lightnvm/pblk-recovery.c, 980:
> pblk_line_replace_data in pblk_recov_l2p
> drivers/lightnvm/pblk-recovery.c, 976:
> spin_lock in pblk_recov_l2p
>
> To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC.
>
> These bugs are found by my static analysis tool DSAC.
>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
> drivers/lightnvm/pblk-core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index ed9cc977c8b3..5d915c93b6cf 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -802,7 +802,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
>
> memset(&rqd, 0, sizeof(struct nvm_rq));
>
> - rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
> + rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_ATOMIC,
> &rqd.dma_meta_list);
> if (!rqd.meta_list)
> return -ENOMEM;
> @@ -810,7 +810,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
> rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size;
> rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size;
>
> - bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_KERNEL);
> + bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_ATOMIC);
> if (IS_ERR(bio)) {
> ret = PTR_ERR(bio);
> goto free_ppa_list;
>
Javier,
What do you think? I'm OK with applying this, but one could also move
the allocs outside the spinlocks?
-Matias
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] lightnvm: pblk: Fix two sleep-in-atomic-context bugs in pblk_line_submit_smeta_io()
2018-09-04 10:11 ` Matias Bjørling
@ 2018-09-04 17:52 ` Javier Gonzalez
2018-09-05 8:40 ` Jia-Ju Bai
0 siblings, 1 reply; 4+ messages in thread
From: Javier Gonzalez @ 2018-09-04 17:52 UTC (permalink / raw)
To: Matias Bjørling
Cc: baijiaju1990, linux-block, linux-kernel, Hans Holmberg
[-- Attachment #1: Type: text/plain, Size: 3045 bytes --]
> On 4 Sep 2018, at 03.11, Matias Bjørling <mb@lightnvm.io> wrote:
>
> On 09/01/2018 01:53 PM, Jia-Ju Bai wrote:
>> The driver may sleep with holding a spinlock.
>> The function call paths (from bottom to top) in Linux-4.16 are:
>> [FUNC] nvm_dev_dma_alloc(GFP_KERNEL)
>> drivers/lightnvm/pblk-core.c, 754:
>> nvm_dev_dma_alloc in pblk_line_submit_smeta_io
>> drivers/lightnvm/pblk-core.c, 1048:
>> pblk_line_submit_smeta_io in pblk_line_init_bb
>> drivers/lightnvm/pblk-core.c, 1434:
>> pblk_line_init_bb in pblk_line_replace_data
>> drivers/lightnvm/pblk-recovery.c, 980:
>> pblk_line_replace_data in pblk_recov_l2p
>> drivers/lightnvm/pblk-recovery.c, 976:
>> spin_lock in pblk_recov_l2p
>> [FUNC] bio_map_kern(GFP_KERNEL)
>> drivers/lightnvm/pblk-core.c, 762:
>> bio_map_kern in pblk_line_submit_smeta_io
>> drivers/lightnvm/pblk-core.c, 1048:
>> pblk_line_submit_smeta_io in pblk_line_init_bb
>> drivers/lightnvm/pblk-core.c, 1434:
>> pblk_line_init_bb in pblk_line_replace_data
>> drivers/lightnvm/pblk-recovery.c, 980:
>> pblk_line_replace_data in pblk_recov_l2p
>> drivers/lightnvm/pblk-recovery.c, 976:
>> spin_lock in pblk_recov_l2p
>> To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC.
>> These bugs are found by my static analysis tool DSAC.
>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>> ---
>> drivers/lightnvm/pblk-core.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
>> index ed9cc977c8b3..5d915c93b6cf 100644
>> --- a/drivers/lightnvm/pblk-core.c
>> +++ b/drivers/lightnvm/pblk-core.c
>> @@ -802,7 +802,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
>> memset(&rqd, 0, sizeof(struct nvm_rq));
>> - rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
>> + rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_ATOMIC,
>> &rqd.dma_meta_list);
>> if (!rqd.meta_list)
>> return -ENOMEM;
>> @@ -810,7 +810,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
>> rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size;
>> rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size;
>> - bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_KERNEL);
>> + bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_ATOMIC);
>> if (IS_ERR(bio)) {
>> ret = PTR_ERR(bio);
>> goto free_ppa_list;
>
> Javier,
>
> What do you think? I'm OK with applying this, but one could also move
> the allocs outside the spinlocks?
>
Definitely better to take the allocation out of the spin_lock(), as all
line preparations are made to be lock free.
It is fairly simple to fix this, as it only occurs when calling
pblk_line_replace_data() from pblk_recov_l2p(). Here the lock can be
inside the if statement to only cover text_and_clear_bit() and to the
else statement to cover it entirely.
Jia-Ju Bai: Do you want to send a patch for this?
Javier
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] lightnvm: pblk: Fix two sleep-in-atomic-context bugs in pblk_line_submit_smeta_io()
2018-09-04 17:52 ` Javier Gonzalez
@ 2018-09-05 8:40 ` Jia-Ju Bai
0 siblings, 0 replies; 4+ messages in thread
From: Jia-Ju Bai @ 2018-09-05 8:40 UTC (permalink / raw)
To: Javier Gonzalez, Matias Bjørling
Cc: linux-block, linux-kernel, Hans Holmberg
On 2018/9/5 1:52, Javier Gonzalez wrote:
>> On 4 Sep 2018, at 03.11, Matias Bjørling <mb@lightnvm.io> wrote:
>>
>> On 09/01/2018 01:53 PM, Jia-Ju Bai wrote:
>>> The driver may sleep with holding a spinlock.
>>> The function call paths (from bottom to top) in Linux-4.16 are:
>>> [FUNC] nvm_dev_dma_alloc(GFP_KERNEL)
>>> drivers/lightnvm/pblk-core.c, 754:
>>> nvm_dev_dma_alloc in pblk_line_submit_smeta_io
>>> drivers/lightnvm/pblk-core.c, 1048:
>>> pblk_line_submit_smeta_io in pblk_line_init_bb
>>> drivers/lightnvm/pblk-core.c, 1434:
>>> pblk_line_init_bb in pblk_line_replace_data
>>> drivers/lightnvm/pblk-recovery.c, 980:
>>> pblk_line_replace_data in pblk_recov_l2p
>>> drivers/lightnvm/pblk-recovery.c, 976:
>>> spin_lock in pblk_recov_l2p
>>> [FUNC] bio_map_kern(GFP_KERNEL)
>>> drivers/lightnvm/pblk-core.c, 762:
>>> bio_map_kern in pblk_line_submit_smeta_io
>>> drivers/lightnvm/pblk-core.c, 1048:
>>> pblk_line_submit_smeta_io in pblk_line_init_bb
>>> drivers/lightnvm/pblk-core.c, 1434:
>>> pblk_line_init_bb in pblk_line_replace_data
>>> drivers/lightnvm/pblk-recovery.c, 980:
>>> pblk_line_replace_data in pblk_recov_l2p
>>> drivers/lightnvm/pblk-recovery.c, 976:
>>> spin_lock in pblk_recov_l2p
>>> To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC.
>>> These bugs are found by my static analysis tool DSAC.
>>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>>> ---
>>> drivers/lightnvm/pblk-core.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
>>> index ed9cc977c8b3..5d915c93b6cf 100644
>>> --- a/drivers/lightnvm/pblk-core.c
>>> +++ b/drivers/lightnvm/pblk-core.c
>>> @@ -802,7 +802,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
>>> memset(&rqd, 0, sizeof(struct nvm_rq));
>>> - rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
>>> + rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_ATOMIC,
>>> &rqd.dma_meta_list);
>>> if (!rqd.meta_list)
>>> return -ENOMEM;
>>> @@ -810,7 +810,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
>>> rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size;
>>> rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size;
>>> - bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_KERNEL);
>>> + bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_ATOMIC);
>>> if (IS_ERR(bio)) {
>>> ret = PTR_ERR(bio);
>>> goto free_ppa_list;
>> Javier,
>>
>> What do you think? I'm OK with applying this, but one could also move
>> the allocs outside the spinlocks?
>>
> Definitely better to take the allocation out of the spin_lock(), as all
> line preparations are made to be lock free.
>
> It is fairly simple to fix this, as it only occurs when calling
> pblk_line_replace_data() from pblk_recov_l2p(). Here the lock can be
> inside the if statement to only cover text_and_clear_bit() and to the
> else statement to cover it entirely.
>
> Jia-Ju Bai: Do you want to send a patch for this?
Okay, Javier.
I sent a patch just now, please have a look.
Best wishes,
Jia-Ju Bai
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-09-01 11:53 [PATCH] lightnvm: pblk: Fix two sleep-in-atomic-context bugs in pblk_line_submit_smeta_io() Jia-Ju Bai
2018-09-04 10:11 ` Matias Bjørling
2018-09-04 17:52 ` Javier Gonzalez
2018-09-05 8:40 ` Jia-Ju Bai
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