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bcachefs: Zero btree_paths on allocation

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This fixes a bug in the cycle detector, bch2_check_for_deadlock() - we
have to make sure the node pointers in the btree paths array are set to
something not-garbage before another thread may see them.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2023-08-13 18:15:53 -04:00
parent e9679b4a06
commit ff5b741c25
1 changed files with 7 additions and 5 deletions
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12
fs/bcachefs/btree_iter.c
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@ -2898,12 +2898,14 @@ static void bch2_trans_alloc_paths(struct btree_trans *trans, struct bch_fs *c)
#ifdef __KERNEL__ #ifdef __KERNEL__
p = this_cpu_xchg(c->btree_paths_bufs->path, NULL); p = this_cpu_xchg(c->btree_paths_bufs->path, NULL);
#endif #endif
if (!p) if (!p) {
p = mempool_alloc(&trans->c->btree_paths_pool, GFP_NOFS); p = mempool_alloc(&trans->c->btree_paths_pool, GFP_NOFS);
/* /*
* paths need to be zeroed, bch2_check_for_deadlock looks at paths in * paths need to be zeroed, bch2_check_for_deadlock looks at
* other threads * paths in other threads
*/ */
memset(p, 0, paths_bytes);
}
trans->paths = p; p += paths_bytes; trans->paths = p; p += paths_bytes;
trans->updates = p; p += updates_bytes; trans->updates = p; p += updates_bytes;