thunderbolt: Fix NULL dereference in tb_remove_work()grafted

There is a slight race between tb_remove_work() and tb_domain_remove()
which leads to dereferencing a NULL tb->root_switch pointer inside
tb_free_unplugged_xdomains():

        Thread A                            Thread B

  tb_remove_work()
                                    tb_domain_remove()
                                      mutex_lock(&tb->lock)
                                      tb_stop()
                                        /* doesn't cancel a running callback */
                                        cancel_delayed_work(&tcm->remove_work)
                                        ...
                                        tb_switch_remove(tb->root_switch)
                                        tb->root_switch = NULL
                                      mutex_unlock(&tb->lock)
    mutex_lock(&tb->lock)
    ...
    /* without checking ->root_switch */
    tb_free_unplugged_xdomains(tb->root_switch)
    mutex_unlock(&tb->lock)

Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without
holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains()
out of the &tb->lock section and the check for tb->root_switch, in
particular.  It states:

  For this reason separate removing the XDomain from the topology data
  structures (where we need the lock) from unregistering the device from
  the bus (where remove callbacks of the drivers are being called).

tb_free_unplugged_xdomains() belongs to the former group of functions
requiring the lock.  And it also calls tb_xdomain_remove() which should
only be called with &tb->lock held.

Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.

Fixes: a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 505 insertions, 0 deletions

diff --git a/include/trace/events/bcache.h b/include/trace/events/bcache.h
new file mode 100644
index 000000000..899fdacf5
--- /dev/null
+++ b/include/trace/events/bcache.h
@@ -0,0 +1,505 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bcache
+
+#if !defined(_TRACE_BCACHE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_BCACHE_H
+
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(bcache_request,
+	TP_PROTO(struct bcache_device *d, struct bio *bio),
+	TP_ARGS(d, bio),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev			)
+		__field(unsigned int,	orig_major		)
+		__field(unsigned int,	orig_minor		)
+		__field(sector_t,	sector			)
+		__field(dev_t,		orig_sector		)
+		__field(unsigned int,	nr_sector		)
+		__array(char,		rwbs,	6		)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio_dev(bio);
+		__entry->orig_major	= d->disk->major;
+		__entry->orig_minor	= d->disk->first_minor;
+		__entry->sector		= bio->bi_iter.bi_sector;
+		__entry->orig_sector	= bio->bi_iter.bi_sector - 16;
+		__entry->nr_sector	= bio->bi_iter.bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
+	),
+
+	TP_printk("%d,%d %s %llu + %u (from %d,%d @ %llu)",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->rwbs, (unsigned long long)__entry->sector,
+		  __entry->nr_sector, __entry->orig_major, __entry->orig_minor,
+		  (unsigned long long)__entry->orig_sector)
+);
+
+DECLARE_EVENT_CLASS(bkey,
+	TP_PROTO(struct bkey *k),
+	TP_ARGS(k),
+
+	TP_STRUCT__entry(
+		__field(u32,	size				)
+		__field(u32,	inode				)
+		__field(u64,	offset				)
+		__field(bool,	dirty				)
+	),
+
+	TP_fast_assign(
+		__entry->inode	= KEY_INODE(k);
+		__entry->offset	= KEY_OFFSET(k);
+		__entry->size	= KEY_SIZE(k);
+		__entry->dirty	= KEY_DIRTY(k);
+	),
+
+	TP_printk("%u:%llu len %u dirty %u", __entry->inode,
+		  __entry->offset, __entry->size, __entry->dirty)
+);
+
+DECLARE_EVENT_CLASS(btree_node,
+	TP_PROTO(struct btree *b),
+	TP_ARGS(b),
+
+	TP_STRUCT__entry(
+		__field(size_t,		bucket			)
+	),
+
+	TP_fast_assign(
+		__entry->bucket	= PTR_BUCKET_NR(b->c, &b->key, 0);
+	),
+
+	TP_printk("bucket %zu", __entry->bucket)
+);
+
+/* request.c */
+
+DEFINE_EVENT(bcache_request, bcache_request_start,
+	TP_PROTO(struct bcache_device *d, struct bio *bio),
+	TP_ARGS(d, bio)
+);
+
+DEFINE_EVENT(bcache_request, bcache_request_end,
+	TP_PROTO(struct bcache_device *d, struct bio *bio),
+	TP_ARGS(d, bio)
+);
+
+DECLARE_EVENT_CLASS(bcache_bio,
+	TP_PROTO(struct bio *bio),
+	TP_ARGS(bio),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev			)
+		__field(sector_t,	sector			)
+		__field(unsigned int,	nr_sector		)
+		__array(char,		rwbs,	6		)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio_dev(bio);
+		__entry->sector		= bio->bi_iter.bi_sector;
+		__entry->nr_sector	= bio->bi_iter.bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
+	),
+
+	TP_printk("%d,%d  %s %llu + %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  (unsigned long long)__entry->sector, __entry->nr_sector)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_bypass_sequential,
+	TP_PROTO(struct bio *bio),
+	TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_bypass_congested,
+	TP_PROTO(struct bio *bio),
+	TP_ARGS(bio)
+);
+
+TRACE_EVENT(bcache_read,
+	TP_PROTO(struct bio *bio, bool hit, bool bypass),
+	TP_ARGS(bio, hit, bypass),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev			)
+		__field(sector_t,	sector			)
+		__field(unsigned int,	nr_sector		)
+		__array(char,		rwbs,	6		)
+		__field(bool,		cache_hit		)
+		__field(bool,		bypass			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio_dev(bio);
+		__entry->sector		= bio->bi_iter.bi_sector;
+		__entry->nr_sector	= bio->bi_iter.bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
+		__entry->cache_hit = hit;
+		__entry->bypass = bypass;
+	),
+
+	TP_printk("%d,%d  %s %llu + %u hit %u bypass %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->rwbs, (unsigned long long)__entry->sector,
+		  __entry->nr_sector, __entry->cache_hit, __entry->bypass)
+);
+
+TRACE_EVENT(bcache_write,
+	TP_PROTO(struct cache_set *c, u64 inode, struct bio *bio,
+		bool writeback, bool bypass),
+	TP_ARGS(c, inode, bio, writeback, bypass),
+
+	TP_STRUCT__entry(
+		__array(char,		uuid,	16		)
+		__field(u64,		inode			)
+		__field(sector_t,	sector			)
+		__field(unsigned int,	nr_sector		)
+		__array(char,		rwbs,	6		)
+		__field(bool,		writeback		)
+		__field(bool,		bypass			)
+	),
+
+	TP_fast_assign(
+		memcpy(__entry->uuid, c->set_uuid, 16);
+		__entry->inode		= inode;
+		__entry->sector		= bio->bi_iter.bi_sector;
+		__entry->nr_sector	= bio->bi_iter.bi_size >> 9;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
+		__entry->writeback = writeback;
+		__entry->bypass = bypass;
+	),
+
+	TP_printk("%pU inode %llu  %s %llu + %u hit %u bypass %u",
+		  __entry->uuid, __entry->inode,
+		  __entry->rwbs, (unsigned long long)__entry->sector,
+		  __entry->nr_sector, __entry->writeback, __entry->bypass)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_read_retry,
+	TP_PROTO(struct bio *bio),
+	TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bkey, bcache_cache_insert,
+	TP_PROTO(struct bkey *k),
+	TP_ARGS(k)
+);
+
+/* Journal */
+
+DECLARE_EVENT_CLASS(cache_set,
+	TP_PROTO(struct cache_set *c),
+	TP_ARGS(c),
+
+	TP_STRUCT__entry(
+		__array(char,		uuid,	16 )
+	),
+
+	TP_fast_assign(
+		memcpy(__entry->uuid, c->set_uuid, 16);
+	),
+
+	TP_printk("%pU", __entry->uuid)
+);
+
+DEFINE_EVENT(bkey, bcache_journal_replay_key,
+	TP_PROTO(struct bkey *k),
+	TP_ARGS(k)
+);
+
+DEFINE_EVENT(cache_set, bcache_journal_full,
+	TP_PROTO(struct cache_set *c),
+	TP_ARGS(c)
+);
+
+DEFINE_EVENT(cache_set, bcache_journal_entry_full,
+	TP_PROTO(struct cache_set *c),
+	TP_ARGS(c)
+);
+
+TRACE_EVENT(bcache_journal_write,
+	TP_PROTO(struct bio *bio, u32 keys),
+	TP_ARGS(bio, keys),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev			)
+		__field(sector_t,	sector			)
+		__field(unsigned int,	nr_sector		)
+		__array(char,		rwbs,	6		)
+		__field(u32,		nr_keys			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= bio_dev(bio);
+		__entry->sector		= bio->bi_iter.bi_sector;
+		__entry->nr_sector	= bio->bi_iter.bi_size >> 9;
+		__entry->nr_keys	= keys;
+		blk_fill_rwbs(__entry->rwbs, bio->bi_opf);
+	),
+
+	TP_printk("%d,%d  %s %llu + %u keys %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->rwbs,
+		  (unsigned long long)__entry->sector, __entry->nr_sector,
+		  __entry->nr_keys)
+);
+
+/* Btree */
+
+DEFINE_EVENT(cache_set, bcache_btree_cache_cannibalize,
+	TP_PROTO(struct cache_set *c),
+	TP_ARGS(c)
+);
+
+DEFINE_EVENT(btree_node, bcache_btree_read,
+	TP_PROTO(struct btree *b),
+	TP_ARGS(b)
+);
+
+TRACE_EVENT(bcache_btree_write,
+	TP_PROTO(struct btree *b),
+	TP_ARGS(b),
+
+	TP_STRUCT__entry(
+		__field(size_t,		bucket			)
+		__field(unsigned,	block			)
+		__field(unsigned,	keys			)
+	),
+
+	TP_fast_assign(
+		__entry->bucket	= PTR_BUCKET_NR(b->c, &b->key, 0);
+		__entry->block	= b->written;
+		__entry->keys	= b->keys.set[b->keys.nsets].data->keys;
+	),
+
+	TP_printk("bucket %zu written block %u + %u",
+		__entry->bucket, __entry->block, __entry->keys)
+);
+
+DEFINE_EVENT(btree_node, bcache_btree_node_alloc,
+	TP_PROTO(struct btree *b),
+	TP_ARGS(b)
+);
+
+DEFINE_EVENT(cache_set, bcache_btree_node_alloc_fail,
+	TP_PROTO(struct cache_set *c),
+	TP_ARGS(c)
+);
+
+DEFINE_EVENT(btree_node, bcache_btree_node_free,
+	TP_PROTO(struct btree *b),
+	TP_ARGS(b)
+);
+
+TRACE_EVENT(bcache_btree_gc_coalesce,
+	TP_PROTO(unsigned nodes),
+	TP_ARGS(nodes),
+
+	TP_STRUCT__entry(
+		__field(unsigned,	nodes			)
+	),
+
+	TP_fast_assign(
+		__entry->nodes	= nodes;
+	),
+
+	TP_printk("coalesced %u nodes", __entry->nodes)
+);
+
+DEFINE_EVENT(cache_set, bcache_gc_start,
+	TP_PROTO(struct cache_set *c),
+	TP_ARGS(c)
+);
+
+DEFINE_EVENT(cache_set, bcache_gc_end,
+	TP_PROTO(struct cache_set *c),
+	TP_ARGS(c)
+);
+
+DEFINE_EVENT(bkey, bcache_gc_copy,
+	TP_PROTO(struct bkey *k),
+	TP_ARGS(k)
+);
+
+DEFINE_EVENT(bkey, bcache_gc_copy_collision,
+	TP_PROTO(struct bkey *k),
+	TP_ARGS(k)
+);
+
+TRACE_EVENT(bcache_btree_insert_key,
+	TP_PROTO(struct btree *b, struct bkey *k, unsigned op, unsigned status),
+	TP_ARGS(b, k, op, status),
+
+	TP_STRUCT__entry(
+		__field(u64,	btree_node			)
+		__field(u32,	btree_level			)
+		__field(u32,	inode				)
+		__field(u64,	offset				)
+		__field(u32,	size				)
+		__field(u8,	dirty				)
+		__field(u8,	op				)
+		__field(u8,	status				)
+	),
+
+	TP_fast_assign(
+		__entry->btree_node = PTR_BUCKET_NR(b->c, &b->key, 0);
+		__entry->btree_level = b->level;
+		__entry->inode	= KEY_INODE(k);
+		__entry->offset	= KEY_OFFSET(k);
+		__entry->size	= KEY_SIZE(k);
+		__entry->dirty	= KEY_DIRTY(k);
+		__entry->op = op;
+		__entry->status = status;
+	),
+
+	TP_printk("%u for %u at %llu(%u): %u:%llu len %u dirty %u",
+		  __entry->status, __entry->op,
+		  __entry->btree_node, __entry->btree_level,
+		  __entry->inode, __entry->offset,
+		  __entry->size, __entry->dirty)
+);
+
+DECLARE_EVENT_CLASS(btree_split,
+	TP_PROTO(struct btree *b, unsigned keys),
+	TP_ARGS(b, keys),
+
+	TP_STRUCT__entry(
+		__field(size_t,		bucket			)
+		__field(unsigned,	keys			)
+	),
+
+	TP_fast_assign(
+		__entry->bucket	= PTR_BUCKET_NR(b->c, &b->key, 0);
+		__entry->keys	= keys;
+	),
+
+	TP_printk("bucket %zu keys %u", __entry->bucket, __entry->keys)
+);
+
+DEFINE_EVENT(btree_split, bcache_btree_node_split,
+	TP_PROTO(struct btree *b, unsigned keys),
+	TP_ARGS(b, keys)
+);
+
+DEFINE_EVENT(btree_split, bcache_btree_node_compact,
+	TP_PROTO(struct btree *b, unsigned keys),
+	TP_ARGS(b, keys)
+);
+
+DEFINE_EVENT(btree_node, bcache_btree_set_root,
+	TP_PROTO(struct btree *b),
+	TP_ARGS(b)
+);
+
+TRACE_EVENT(bcache_keyscan,
+	TP_PROTO(unsigned nr_found,
+		 unsigned start_inode, uint64_t start_offset,
+		 unsigned end_inode, uint64_t end_offset),
+	TP_ARGS(nr_found,
+		start_inode, start_offset,
+		end_inode, end_offset),
+
+	TP_STRUCT__entry(
+		__field(__u32,	nr_found			)
+		__field(__u32,	start_inode			)
+		__field(__u64,	start_offset			)
+		__field(__u32,	end_inode			)
+		__field(__u64,	end_offset			)
+	),
+
+	TP_fast_assign(
+		__entry->nr_found	= nr_found;
+		__entry->start_inode	= start_inode;
+		__entry->start_offset	= start_offset;
+		__entry->end_inode	= end_inode;
+		__entry->end_offset	= end_offset;
+	),
+
+	TP_printk("found %u keys from %u:%llu to %u:%llu", __entry->nr_found,
+		  __entry->start_inode, __entry->start_offset,
+		  __entry->end_inode, __entry->end_offset)
+);
+
+/* Allocator */
+
+TRACE_EVENT(bcache_invalidate,
+	TP_PROTO(struct cache *ca, size_t bucket),
+	TP_ARGS(ca, bucket),
+
+	TP_STRUCT__entry(
+		__field(unsigned,	sectors			)
+		__field(dev_t,		dev			)
+		__field(__u64,		offset			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= ca->bdev->bd_dev;
+		__entry->offset		= bucket << ca->set->bucket_bits;
+		__entry->sectors	= GC_SECTORS_USED(&ca->buckets[bucket]);
+	),
+
+	TP_printk("invalidated %u sectors at %d,%d sector=%llu",
+		  __entry->sectors, MAJOR(__entry->dev),
+		  MINOR(__entry->dev), __entry->offset)
+);
+
+TRACE_EVENT(bcache_alloc,
+	TP_PROTO(struct cache *ca, size_t bucket),
+	TP_ARGS(ca, bucket),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev			)
+		__field(__u64,		offset			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= ca->bdev->bd_dev;
+		__entry->offset		= bucket << ca->set->bucket_bits;
+	),
+
+	TP_printk("allocated %d,%d sector=%llu", MAJOR(__entry->dev),
+		  MINOR(__entry->dev), __entry->offset)
+);
+
+TRACE_EVENT(bcache_alloc_fail,
+	TP_PROTO(struct cache *ca, unsigned reserve),
+	TP_ARGS(ca, reserve),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev			)
+		__field(unsigned,	free			)
+		__field(unsigned,	free_inc		)
+		__field(unsigned,	blocked			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= ca->bdev->bd_dev;
+		__entry->free		= fifo_used(&ca->free[reserve]);
+		__entry->free_inc	= fifo_used(&ca->free_inc);
+		__entry->blocked	= atomic_read(&ca->set->prio_blocked);
+	),
+
+	TP_printk("alloc fail %d,%d free %u free_inc %u blocked %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->free,
+		  __entry->free_inc, __entry->blocked)
+);
+
+/* Background writeback */
+
+DEFINE_EVENT(bkey, bcache_writeback,
+	TP_PROTO(struct bkey *k),
+	TP_ARGS(k)
+);
+
+DEFINE_EVENT(bkey, bcache_writeback_collision,
+	TP_PROTO(struct bkey *k),
+	TP_ARGS(k)
+);
+
+#endif /* _TRACE_BCACHE_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>