On 2018/9/5 1:52, Javier Gonzalez wrote:
On 4 Sep 2018, at 03.11, Matias Bjørling <mb@xxxxxxxxxxx> 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@xxxxxxxxx>
---
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
