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SubjectRe: [PATCH v2] lightnvm: divide global reverse translation map into per lun
From
Seems it is the variable pg_offset in rrpc_page_invalidate that cause the panic.
It's a u64 variable we use its low 32bit to store the offset value,
leave the high 32bit in a undetermined status, this will cause
test_and_set_bit access unexpected memory, cause kernel panic.
It's should be initialized to zero before use.

I add some log to verify this assuption, bleow is the log

[ 485.260549] rrpc: paddr: 400 sec_per_blk: 100 offset: ffff880000000000
[ 485.260563] BUG: unable to handle kernel paging request at ffffba0000d4f230

offset value ffff880000000000 may be passed to test_and_set_bit instead of 0.

2016-03-21 18:25 GMT+08:00 Matias Bjørling <mb@lightnvm.io>:
> On 03/20/2016 06:51 AM, Wenwei Tao wrote:
>>
>> Divide the target's global reverse translation map into per lun,
>> to prepare support for the non-continuous lun target creation.
>>
>> Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
>> ---
>>
>> Changes since v1
>> -fix merge/rebase mistake in rrpc_block_map_update().
>> -remove variables poffset and lun_offset in rrpc structure
>> since no one use them now.
>>
>> drivers/lightnvm/rrpc.c | 181
>> +++++++++++++++++++++++++++--------------------
>> drivers/lightnvm/rrpc.h | 9 ++-
>> include/linux/lightnvm.h | 1 +
>> 3 files changed, 111 insertions(+), 80 deletions(-)
>>
>> diff --git a/drivers/lightnvm/rrpc.c b/drivers/lightnvm/rrpc.c
>> index 3ab6495..88e2ce5 100644
>> --- a/drivers/lightnvm/rrpc.c
>> +++ b/drivers/lightnvm/rrpc.c
>> @@ -23,28 +23,35 @@ static int rrpc_submit_io(struct rrpc *rrpc, struct
>> bio *bio,
>> struct nvm_rq *rqd, unsigned long flags);
>>
>> #define rrpc_for_each_lun(rrpc, rlun, i) \
>> - for ((i) = 0, rlun = &(rrpc)->luns[0]; \
>> - (i) < (rrpc)->nr_luns; (i)++, rlun =
>> &(rrpc)->luns[(i)])
>> + for ((i) = 0, rlun = &(rrpc)->luns[0]; \
>> + (i) < (rrpc)->nr_luns; (i)++, rlun = &(rrpc)->luns[(i)])
>> +
>> +static inline u64 lun_poffset(struct nvm_lun *lun, struct nvm_dev *dev)
>> +{
>> + return lun->id * dev->sec_per_lun;
>> +}
>>
>> static void rrpc_page_invalidate(struct rrpc *rrpc, struct rrpc_addr *a)
>> {
>> struct rrpc_block *rblk = a->rblk;
>> - unsigned int pg_offset;
>> + struct rrpc_lun *rlun = rblk->rlun;
>> + u64 pg_offset;
>>
>> - lockdep_assert_held(&rrpc->rev_lock);
>> + lockdep_assert_held(&rlun->rev_lock);
>>
>> if (a->addr == ADDR_EMPTY || !rblk)
>> return;
>>
>> spin_lock(&rblk->lock);
>>
>> - div_u64_rem(a->addr, rrpc->dev->sec_per_blk, &pg_offset);
>> + div_u64_rem(a->addr, rrpc->dev->sec_per_blk, (u32 *)&pg_offset);
>> WARN_ON(test_and_set_bit(pg_offset, rblk->invalid_pages));
>> rblk->nr_invalid_pages++;
>>
>> spin_unlock(&rblk->lock);
>>
>> - rrpc->rev_trans_map[a->addr - rrpc->poffset].addr = ADDR_EMPTY;
>> + pg_offset = lun_poffset(rlun->parent, rrpc->dev);
>> + rlun->rev_trans_map[a->addr - pg_offset].addr = ADDR_EMPTY;
>> }
>>
>> static void rrpc_invalidate_range(struct rrpc *rrpc, sector_t slba,
>> @@ -52,14 +59,15 @@ static void rrpc_invalidate_range(struct rrpc *rrpc,
>> sector_t slba,
>> {
>> sector_t i;
>>
>> - spin_lock(&rrpc->rev_lock);
>> for (i = slba; i < slba + len; i++) {
>> struct rrpc_addr *gp = &rrpc->trans_map[i];
>> + struct rrpc_lun *rlun = gp->rblk->rlun;
>>
>> + spin_lock(&rlun->rev_lock);
>> rrpc_page_invalidate(rrpc, gp);
>> + spin_unlock(&rlun->rev_lock);
>> gp->rblk = NULL;
>> }
>> - spin_unlock(&rrpc->rev_lock);
>> }
>>
>> static struct nvm_rq *rrpc_inflight_laddr_acquire(struct rrpc *rrpc,
>> @@ -116,15 +124,6 @@ static int block_is_full(struct rrpc *rrpc, struct
>> rrpc_block *rblk)
>> return (rblk->next_page == rrpc->dev->sec_per_blk);
>> }
>>
>> -/* Calculate relative addr for the given block, considering instantiated
>> LUNs */
>> -static u64 block_to_rel_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
>> -{
>> - struct nvm_block *blk = rblk->parent;
>> - int lun_blk = blk->id % (rrpc->dev->blks_per_lun * rrpc->nr_luns);
>> -
>> - return lun_blk * rrpc->dev->sec_per_blk;
>> -}
>> -
>> /* Calculate global addr for the given block */
>> static u64 block_to_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
>> {
>> @@ -291,13 +290,14 @@ static void rrpc_end_sync_bio(struct bio *bio)
>> static int rrpc_move_valid_pages(struct rrpc *rrpc, struct rrpc_block
>> *rblk)
>> {
>> struct request_queue *q = rrpc->dev->q;
>> + struct rrpc_lun *rlun = rblk->rlun;
>> struct rrpc_rev_addr *rev;
>> struct nvm_rq *rqd;
>> struct bio *bio;
>> struct page *page;
>> int slot;
>> int nr_sec_per_blk = rrpc->dev->sec_per_blk;
>> - u64 phys_addr;
>> + u64 phys_addr, poffset;
>> DECLARE_COMPLETION_ONSTACK(wait);
>>
>> if (bitmap_full(rblk->invalid_pages, nr_sec_per_blk))
>> @@ -315,6 +315,7 @@ static int rrpc_move_valid_pages(struct rrpc *rrpc,
>> struct rrpc_block *rblk)
>> return -ENOMEM;
>> }
>>
>> + poffset = lun_poffset(rlun->parent, rrpc->dev);
>> while ((slot = find_first_zero_bit(rblk->invalid_pages,
>> nr_sec_per_blk)) <
>> nr_sec_per_blk) {
>>
>> @@ -322,23 +323,23 @@ static int rrpc_move_valid_pages(struct rrpc *rrpc,
>> struct rrpc_block *rblk)
>> phys_addr = rblk->parent->id * nr_sec_per_blk + slot;
>>
>> try:
>> - spin_lock(&rrpc->rev_lock);
>> + spin_lock(&rlun->rev_lock);
>> /* Get logical address from physical to logical table */
>> - rev = &rrpc->rev_trans_map[phys_addr - rrpc->poffset];
>> + rev = &rlun->rev_trans_map[phys_addr - poffset];
>> /* already updated by previous regular write */
>> if (rev->addr == ADDR_EMPTY) {
>> - spin_unlock(&rrpc->rev_lock);
>> + spin_unlock(&rlun->rev_lock);
>> continue;
>> }
>>
>> rqd = rrpc_inflight_laddr_acquire(rrpc, rev->addr, 1);
>> if (IS_ERR_OR_NULL(rqd)) {
>> - spin_unlock(&rrpc->rev_lock);
>> + spin_unlock(&rlun->rev_lock);
>> schedule();
>> goto try;
>> }
>>
>> - spin_unlock(&rrpc->rev_lock);
>> + spin_unlock(&rlun->rev_lock);
>>
>> /* Perform read to do GC */
>> bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
>> @@ -407,7 +408,7 @@ static void rrpc_block_gc(struct work_struct *work)
>> struct rrpc_block *rblk = gcb->rblk;
>> struct nvm_dev *dev = rrpc->dev;
>> struct nvm_lun *lun = rblk->parent->lun;
>> - struct rrpc_lun *rlun = &rrpc->luns[lun->id - rrpc->lun_offset];
>> + struct rrpc_lun *rlun = lun->private;
>>
>> mempool_free(gcb, rrpc->gcb_pool);
>> pr_debug("nvm: block '%lu' being reclaimed\n", rblk->parent->id);
>> @@ -510,7 +511,7 @@ static void rrpc_gc_queue(struct work_struct *work)
>> struct rrpc_block *rblk = gcb->rblk;
>> struct nvm_lun *lun = rblk->parent->lun;
>> struct nvm_block *blk = rblk->parent;
>> - struct rrpc_lun *rlun = &rrpc->luns[lun->id - rrpc->lun_offset];
>> + struct rrpc_lun *rlun = lun->private;
>>
>> spin_lock(&rlun->lock);
>> list_add_tail(&rblk->prio, &rlun->prio_list);
>> @@ -561,22 +562,25 @@ static struct rrpc_lun *rrpc_get_lun_rr(struct rrpc
>> *rrpc, int is_gc)
>> static struct rrpc_addr *rrpc_update_map(struct rrpc *rrpc, sector_t
>> laddr,
>> struct rrpc_block *rblk, u64
>> paddr)
>> {
>> + struct rrpc_lun *rlun = rblk->rlun;
>> struct rrpc_addr *gp;
>> struct rrpc_rev_addr *rev;
>> + u64 poffset = lun_poffset(rlun->parent, rrpc->dev);
>>
>> BUG_ON(laddr >= rrpc->nr_sects);
>>
>> gp = &rrpc->trans_map[laddr];
>> - spin_lock(&rrpc->rev_lock);
>> + spin_lock(&rlun->rev_lock);
>> +
>> if (gp->rblk)
>> rrpc_page_invalidate(rrpc, gp);
>>
>> gp->addr = paddr;
>> gp->rblk = rblk;
>>
>> - rev = &rrpc->rev_trans_map[gp->addr - rrpc->poffset];
>> + rev = &rlun->rev_trans_map[gp->addr - poffset];
>> rev->addr = laddr;
>> - spin_unlock(&rrpc->rev_lock);
>> + spin_unlock(&rlun->rev_lock);
>>
>> return gp;
>> }
>> @@ -990,7 +994,6 @@ static int rrpc_gc_init(struct rrpc *rrpc)
>>
>> static void rrpc_map_free(struct rrpc *rrpc)
>> {
>> - vfree(rrpc->rev_trans_map);
>> vfree(rrpc->trans_map);
>> }
>>
>> @@ -998,8 +1001,8 @@ static int rrpc_l2p_update(u64 slba, u32 nlb, __le64
>> *entries, void *private)
>> {
>> struct rrpc *rrpc = (struct rrpc *)private;
>> struct nvm_dev *dev = rrpc->dev;
>> - struct rrpc_addr *addr = rrpc->trans_map + slba;
>> - struct rrpc_rev_addr *raddr = rrpc->rev_trans_map;
>> + struct rrpc_addr *addr;
>> + struct rrpc_rev_addr *raddr;
>> u64 elba = slba + nlb;
>> u64 i;
>>
>> @@ -1008,9 +1011,15 @@ static int rrpc_l2p_update(u64 slba, u32 nlb,
>> __le64 *entries, void *private)
>> return -EINVAL;
>> }
>>
>> + slba -= rrpc->soffset >> (ilog2(dev->sec_size) - 9);
>> + addr = rrpc->trans_map + slba;
>> for (i = 0; i < nlb; i++) {
>> + struct rrpc_lun *rlun;
>> + struct nvm_lun *lun;
>> u64 pba = le64_to_cpu(entries[i]);
>> - unsigned int mod;
>> + u64 poffset;
>> + int lunid;
>> +
>> /* LNVM treats address-spaces as silos, LBA and PBA are
>> * equally large and zero-indexed.
>> */
>> @@ -1026,10 +1035,18 @@ static int rrpc_l2p_update(u64 slba, u32 nlb,
>> __le64 *entries, void *private)
>> if (!pba)
>> continue;
>>
>> - div_u64_rem(pba, rrpc->nr_sects, &mod);
>> + lunid = div_u64(pba, dev->sec_per_lun);
>> + lun = dev->mt->get_lun(dev, lunid);
>> +
>> + if (unlikely(!lun))
>> + return -EINVAL;
>> +
>> + rlun = lun->private;
>> + raddr = rlun->rev_trans_map;
>> + poffset = lun_poffset(lun, dev);
>>
>> addr[i].addr = pba;
>> - raddr[mod].addr = slba + i;
>> + raddr[pba - poffset].addr = slba + i;
>> }
>>
>> return 0;
>> @@ -1048,17 +1065,10 @@ static int rrpc_map_init(struct rrpc *rrpc)
>> if (!rrpc->trans_map)
>> return -ENOMEM;
>>
>> - rrpc->rev_trans_map = vmalloc(sizeof(struct rrpc_rev_addr)
>> - * rrpc->nr_sects);
>> - if (!rrpc->rev_trans_map)
>> - return -ENOMEM;
>> -
>> for (i = 0; i < rrpc->nr_sects; i++) {
>> struct rrpc_addr *p = &rrpc->trans_map[i];
>> - struct rrpc_rev_addr *r = &rrpc->rev_trans_map[i];
>>
>> p->addr = ADDR_EMPTY;
>> - r->addr = ADDR_EMPTY;
>> }
>>
>> if (!dev->ops->get_l2p_tbl)
>> @@ -1143,25 +1153,69 @@ static void rrpc_luns_free(struct rrpc *rrpc)
>> if (!lun)
>> break;
>> dev->mt->release_lun(dev, lun->id);
>> + vfree(rlun->rev_trans_map);
>> vfree(rlun->blocks);
>> }
>>
>> kfree(rrpc->luns);
>> + rrpc->luns = NULL;
>> +}
>> +
>> +static int rrpc_lun_init(struct rrpc *rrpc, struct rrpc_lun *rlun,
>> + struct nvm_lun *lun)
>> +{
>> + struct nvm_dev *dev = rrpc->dev;
>> + int i;
>> +
>> + rlun->rev_trans_map = vmalloc(sizeof(struct rrpc_rev_addr) *
>> + dev->sec_per_lun);
>> + if (!rlun->rev_trans_map)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < dev->sec_per_lun; i++) {
>> + struct rrpc_rev_addr *r = &rlun->rev_trans_map[i];
>> +
>> + r->addr = ADDR_EMPTY;
>> + }
>> + rlun->blocks = vzalloc(sizeof(struct rrpc_block) *
>> dev->blks_per_lun);
>> + if (!rlun->blocks) {
>> + vfree(rlun->rev_trans_map);
>> + return -ENOMEM;
>> + }
>> +
>> + for (i = 0; i < dev->blks_per_lun; i++) {
>> + struct rrpc_block *rblk = &rlun->blocks[i];
>> + struct nvm_block *blk = &lun->blocks[i];
>> +
>> + rblk->parent = blk;
>> + rblk->rlun = rlun;
>> + INIT_LIST_HEAD(&rblk->prio);
>> + spin_lock_init(&rblk->lock);
>> + }
>> +
>> + rlun->rrpc = rrpc;
>> + lun->private = rlun;
>> + INIT_LIST_HEAD(&rlun->prio_list);
>> + INIT_LIST_HEAD(&rlun->open_list);
>> + INIT_LIST_HEAD(&rlun->closed_list);
>> + INIT_WORK(&rlun->ws_gc, rrpc_lun_gc);
>> + spin_lock_init(&rlun->lock);
>> + spin_lock_init(&rlun->rev_lock);
>> +
>> + return 0;
>> }
>>
>> static int rrpc_luns_init(struct rrpc *rrpc, int lun_begin, int lun_end)
>> {
>> struct nvm_dev *dev = rrpc->dev;
>> struct rrpc_lun *rlun;
>> - int i, j, ret = -EINVAL;
>> + int i, ret = -EINVAL;
>>
>> if (dev->sec_per_blk > MAX_INVALID_PAGES_STORAGE * BITS_PER_LONG)
>> {
>> pr_err("rrpc: number of pages per block too high.");
>> return -EINVAL;
>> }
>>
>> - spin_lock_init(&rrpc->rev_lock);
>> -
>> rrpc->luns = kcalloc(rrpc->nr_luns, sizeof(struct rrpc_lun),
>>
>> GFP_KERNEL);
>> if (!rrpc->luns)
>> @@ -1183,31 +1237,9 @@ static int rrpc_luns_init(struct rrpc *rrpc, int
>> lun_begin, int lun_end)
>>
>> rlun = &rrpc->luns[i];
>> rlun->parent = lun;
>> - rlun->blocks = vzalloc(sizeof(struct rrpc_block) *
>> - rrpc->dev->blks_per_lun);
>> - if (!rlun->blocks) {
>> - ret = -ENOMEM;
>> + ret = rrpc_lun_init(rrpc, rlun, lun);
>> + if (ret)
>> goto err;
>> - }
>> -
>> - for (j = 0; j < rrpc->dev->blks_per_lun; j++) {
>> - struct rrpc_block *rblk = &rlun->blocks[j];
>> - struct nvm_block *blk = &lun->blocks[j];
>> -
>> - rblk->parent = blk;
>> - rblk->rlun = rlun;
>> - INIT_LIST_HEAD(&rblk->prio);
>> - spin_lock_init(&rblk->lock);
>> - }
>> -
>> - rlun->rrpc = rrpc;
>> - INIT_LIST_HEAD(&rlun->prio_list);
>> - INIT_LIST_HEAD(&rlun->open_list);
>> - INIT_LIST_HEAD(&rlun->closed_list);
>> -
>> - INIT_WORK(&rlun->ws_gc, rrpc_lun_gc);
>> - spin_lock_init(&rlun->lock);
>> -
>> rrpc->total_blocks += dev->blks_per_lun;
>> rrpc->nr_sects += dev->sec_per_lun;
>>
>> @@ -1215,6 +1247,7 @@ static int rrpc_luns_init(struct rrpc *rrpc, int
>> lun_begin, int lun_end)
>>
>> return 0;
>> err:
>> + rrpc_luns_free(rrpc);
>> return ret;
>> }
>>
>> @@ -1288,15 +1321,16 @@ static sector_t rrpc_capacity(void *private)
>> static void rrpc_block_map_update(struct rrpc *rrpc, struct rrpc_block
>> *rblk)
>> {
>> struct nvm_dev *dev = rrpc->dev;
>> + struct rrpc_lun *rlun = rblk->rlun;
>> int offset;
>> struct rrpc_addr *laddr;
>> - u64 bpaddr, paddr, pladdr;
>> + u64 paddr, pladdr, poffset;
>>
>> - bpaddr = block_to_rel_addr(rrpc, rblk);
>> + poffset = lun_poffset(rlun->parent, dev);
>> for (offset = 0; offset < dev->sec_per_blk; offset++) {
>> - paddr = bpaddr + offset;
>> + paddr = block_to_addr(rrpc, rblk) + offset;
>>
>> - pladdr = rrpc->rev_trans_map[paddr].addr;
>> + pladdr = rlun->rev_trans_map[paddr - poffset].addr;
>> if (pladdr == ADDR_EMPTY)
>> continue;
>>
>> @@ -1405,9 +1439,6 @@ static void *rrpc_init(struct nvm_dev *dev, struct
>> gendisk *tdisk,
>> goto err;
>> }
>>
>> - rrpc->poffset = dev->sec_per_lun * lun_begin;
>> - rrpc->lun_offset = lun_begin;
>> -
>> ret = rrpc_core_init(rrpc);
>> if (ret) {
>> pr_err("nvm: rrpc: could not initialize core\n");
>> diff --git a/drivers/lightnvm/rrpc.h b/drivers/lightnvm/rrpc.h
>> index 2653484..590f1b7 100644
>> --- a/drivers/lightnvm/rrpc.h
>> +++ b/drivers/lightnvm/rrpc.h
>> @@ -87,6 +87,10 @@ struct rrpc_lun {
>>
>> struct work_struct ws_gc;
>>
>> + /* store a reverse map for garbage collection */
>> + struct rrpc_rev_addr *rev_trans_map;
>> + spinlock_t rev_lock;
>> +
>> spinlock_t lock;
>> };
>>
>> @@ -98,8 +102,6 @@ struct rrpc {
>> struct gendisk *disk;
>>
>> sector_t soffset; /* logical sector offset */
>> - u64 poffset; /* physical page offset */
>> - int lun_offset;
>>
>> int nr_luns;
>> struct rrpc_lun *luns;
>> @@ -124,9 +126,6 @@ struct rrpc {
>> * addresses are used when writing to the disk block device.
>> */
>> struct rrpc_addr *trans_map;
>> - /* also store a reverse map for garbage collection */
>> - struct rrpc_rev_addr *rev_trans_map;
>> - spinlock_t rev_lock;
>>
>> struct rrpc_inflight inflights;
>>
>> diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
>> index cdcb2cc..419a3db 100644
>> --- a/include/linux/lightnvm.h
>> +++ b/include/linux/lightnvm.h
>> @@ -276,6 +276,7 @@ struct nvm_lun {
>> spinlock_t lock;
>>
>> struct nvm_block *blocks;
>> + void *private;
>> };
>>
>> enum {
>>
>
> It seems like there is a race-condition when GC hits. It panics on
> page_invalidation. You can test with the following fio script:
>
> [global]
> bs=4k
> ioengine=libaio
> iodepth=1
> size=1G
> direct=1
> rw=randwrite
> time_based
> runtime=300
>
> [p1]
> numjobs=1
> filename=/dev/test2
>

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