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bcachefs: Fix NULL ptr dereference in btree_node_iter_and_journal_peek

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Add NULL check for key returned from bch2_btree_and_journal_iter_peek in
btree_node_iter_and_journal_peek to avoid NULL ptr dereference in
bch2_bkey_buf_reassemble.

When key returned from bch2_btree_and_journal_iter_peek is NULL it means
that btree topology needs repair. Print topology error message with
position at which node wasn't found, its parent node information and
btree_id with level.

Return error code returned by bch2_topology_error to ensure that topology
error is handled properly by recovery.

Reported-by: syzbot+005ef9aa519f30d97657@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=005ef9aa519f30d97657
Fixes: 5222a4607c ("bcachefs: BTREE_ITER_WITH_JOURNAL")
Suggested-by: Alan Huang <mmpgouride@gmail.com>
Suggested-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Piotr Zalewski <pZ010001011111@proton.me>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Piotr Zalewski 2024-10-27 19:46:52 +00:00 committed by Kent Overstreet
parent ca959e328b
commit 3726a1970b
1 changed files with 13 additions and 0 deletions
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13
fs/bcachefs/btree_iter.c
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@ -882,6 +882,18 @@ static noinline int btree_node_iter_and_journal_peek(struct btree_trans *trans,
__bch2_btree_and_journal_iter_init_node_iter(trans, &jiter, l->b, l->iter, path->pos); __bch2_btree_and_journal_iter_init_node_iter(trans, &jiter, l->b, l->iter, path->pos);
k = bch2_btree_and_journal_iter_peek(&jiter); k = bch2_btree_and_journal_iter_peek(&jiter);
if (!k.k) {
struct printbuf buf = PRINTBUF;
prt_str(&buf, "node not found at pos ");
bch2_bpos_to_text(&buf, path->pos);
prt_str(&buf, " at btree ");
bch2_btree_pos_to_text(&buf, c, l->b);
ret = bch2_fs_topology_error(c, "%s", buf.buf);
printbuf_exit(&buf);
goto err;
}
bch2_bkey_buf_reassemble(out, c, k); bch2_bkey_buf_reassemble(out, c, k);
@ -889,6 +901,7 @@ static noinline int btree_node_iter_and_journal_peek(struct btree_trans *trans,
c->opts.btree_node_prefetch) c->opts.btree_node_prefetch)
ret = btree_path_prefetch_j(trans, path, &jiter); ret = btree_path_prefetch_j(trans, path, &jiter);
err:
bch2_btree_and_journal_iter_exit(&jiter); bch2_btree_and_journal_iter_exit(&jiter);
return ret; return ret;
} }