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lightnvm: pblk: fix two sleep-in-atomic-context bugs 

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>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
Jia-Ju Bai 2018-10-09 13:12:00 +02:00 committed by Jens Axboe
parent bf82fa2f58
commit 7325b4bbe5
1 changed files with 4 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/lightnvm/pblk-recovery.c
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@ -966,12 +966,14 @@ next:
}
}
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) {
@ -979,8 +981,8 @@ next:
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);