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| author | Alan Huang <mmpgouride@gmail.com> | 2025-02-26 17:33:22 +0800 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2025-02-26 19:31:05 -0500 |
| commit | 677bdb7346b6fd806ea45b11cbfe36de0b0cd644 (patch) | |
| tree | 7d3444ff37a1d2ba06d4b7da078f1fc0de9d86c2 /fs/bcachefs/btree_cache.c | |
| parent | 7909d1fb90e290ffd7b8570f4e2f97fe2fb381d0 (diff) | |
| download | linux-next-677bdb7346b6fd806ea45b11cbfe36de0b0cd644.tar.gz linux-next-677bdb7346b6fd806ea45b11cbfe36de0b0cd644.zip | |
bcachefs: Fix deadlock
This fixes two deadlocks:
1.pcpu_alloc_mutex involved one as pointed by syzbot[1]
2.recursion deadlock.
The root cause is that we hold the bc lock during alloc_percpu, fix it
by following the pattern used by __btree_node_mem_alloc().
[1] https://lore.kernel.org/all/66f97d9a.050a0220.6bad9.001d.GAE@google.com/T/
Reported-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
Tested-by: syzbot+fe63f377148a6371a9db@syzkaller.appspotmail.com
Signed-off-by: Alan Huang <mmpgouride@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Diffstat (limited to 'fs/bcachefs/btree_cache.c')
| -rw-r--r-- | fs/bcachefs/btree_cache.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c index ca755e8d1a37..1ec1f90e0eb3 100644 --- a/fs/bcachefs/btree_cache.c +++ b/fs/bcachefs/btree_cache.c @@ -203,7 +203,7 @@ struct btree *__bch2_btree_node_mem_alloc(struct bch_fs *c) return NULL; } - bch2_btree_lock_init(&b->c, 0); + bch2_btree_lock_init(&b->c, 0, GFP_KERNEL); __bch2_btree_node_to_freelist(bc, b); return b; @@ -795,17 +795,18 @@ struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_rea } b = __btree_node_mem_alloc(c, GFP_NOWAIT|__GFP_NOWARN); - if (!b) { + if (b) { + bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0, GFP_NOWAIT); + } else { mutex_unlock(&bc->lock); bch2_trans_unlock(trans); b = __btree_node_mem_alloc(c, GFP_KERNEL); if (!b) goto err; + bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0, GFP_KERNEL); mutex_lock(&bc->lock); } - bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0); - BUG_ON(!six_trylock_intent(&b->c.lock)); BUG_ON(!six_trylock_write(&b->c.lock)); |