lkml.org 
[lkml]   [2018]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2] lightnvm: pblk-recovery: lightnvm: pblk: Fix two sleep-in-atomic-context bugs
From
Date
On 09/06/2018 03:18 PM, Javier Gonzalez wrote:
>> On 5 Sep 2018, at 01.40, Jia-Ju Bai <baijiaju1990@gmail.com> 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, the call to pblk_line_replace_data()
>> is moved out of the spinlock protection.
>>
>> These bugs are found by my static analysis tool DSAC.
>>
>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>> ---
>> v2:
>> * Move the call to pblk_line_replace_data() out of the spinlock
>> protection, instead of v1 that changes GFP_KERNEL to GFP_ATOMIC in
>> the calls to bio_map_kern() and nvm_dev_dma_alloc().
>> Thanks Javier for good advice.
>> ---
>> drivers/lightnvm/pblk-recovery.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/lightnvm/pblk-recovery.c b/drivers/lightnvm/pblk-recovery.c
>> index 3a5069183859..5fde414d78bb 100644
>> --- a/drivers/lightnvm/pblk-recovery.c
>> +++ b/drivers/lightnvm/pblk-recovery.c
>> @@ -955,12 +955,14 @@ struct pblk_line *pblk_recov_l2p(struct pblk *pblk)
>> }
>> }
>>
>> - spin_lock(&l_mg->free_lock);
>> if (!open_lines) {
>> + spin_lock(&l_mg->free_lock);
>> WARN_ON_ONCE(!test_and_clear_bit(meta_line,
>> &l_mg->meta_bitmap));
>> + spin_unlock(&l_mg->free_lock);
>> pblk_line_replace_data(pblk);
>> } else {
>> + spin_lock(&l_mg->free_lock);
>> /* Allocate next line for preparation */
>> l_mg->data_next = pblk_line_get(pblk);
>> if (l_mg->data_next) {
>> @@ -968,8 +970,8 @@ struct pblk_line *pblk_recov_l2p(struct pblk *pblk)
>> l_mg->data_next->type = PBLK_LINETYPE_DATA;
>> is_next = 1;
>> }
>> + spin_unlock(&l_mg->free_lock);
>> }
>> - spin_unlock(&l_mg->free_lock);
>>
>> if (is_next)
>> pblk_line_erase(pblk, l_mg->data_next);
>> --
>> 2.17.0
>
> It looks good to me. Thanks Jia-Ju.
>
> Reviewed-by: Javier González <javier@cnexlabs.com>
>

Thanks. Applied for 4.20.

\
 
 \ /
  Last update: 2018-09-07 12:02    [W:1.784 / U:0.148 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site