From a54f78def73d847cb060b18c4e4a3d1d26c9ca6d Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Fri, 27 May 2022 10:22:56 +1000
Subject: [PATCH] xfs: don't leak btree cursor when insrec fails after a split
Git-commit: a54f78def73d847cb060b18c4e4a3d1d26c9ca6d
Patch-mainline: v5.19-rc1
References: git-fixes
The recent patch to improve btree cycle checking caused a regression
when I rebased the in-memory btree branch atop the 5.19 for-next branch,
because in-memory short-pointer btrees do not have AG numbers. This
produced the following complaint from kmemleak:
unreferenced object 0xffff88803d47dde8 (size 264):
comm "xfs_io", pid 4889, jiffies 4294906764 (age 24.072s)
hex dump (first 32 bytes):
90 4d 0b 0f 80 88 ff ff 00 a0 bd 05 80 88 ff ff .M..............
e0 44 3a a0 ff ff ff ff 00 df 08 06 80 88 ff ff .D:.............
backtrace:
[<ffffffffa0388059>] xfbtree_dup_cursor+0x49/0xc0 [xfs]
[<ffffffffa029887b>] xfs_btree_dup_cursor+0x3b/0x200 [xfs]
[<ffffffffa029af5d>] __xfs_btree_split+0x6ad/0x820 [xfs]
[<ffffffffa029b130>] xfs_btree_split+0x60/0x110 [xfs]
[<ffffffffa029f6da>] xfs_btree_make_block_unfull+0x19a/0x1f0 [xfs]
[<ffffffffa029fada>] xfs_btree_insrec+0x3aa/0x810 [xfs]
[<ffffffffa029fff3>] xfs_btree_insert+0xb3/0x240 [xfs]
[<ffffffffa02cb729>] xfs_rmap_insert+0x99/0x200 [xfs]
[<ffffffffa02cf142>] xfs_rmap_map_shared+0x192/0x5f0 [xfs]
[<ffffffffa02cf60b>] xfs_rmap_map_raw+0x6b/0x90 [xfs]
[<ffffffffa0384a85>] xrep_rmap_stash+0xd5/0x1d0 [xfs]
[<ffffffffa0384dc0>] xrep_rmap_visit_bmbt+0xa0/0xf0 [xfs]
[<ffffffffa0384fb6>] xrep_rmap_scan_iext+0x56/0xa0 [xfs]
[<ffffffffa03850d8>] xrep_rmap_scan_ifork+0xd8/0x160 [xfs]
[<ffffffffa0385195>] xrep_rmap_scan_inode+0x35/0x80 [xfs]
[<ffffffffa03852ee>] xrep_rmap_find_rmaps+0x10e/0x270 [xfs]
I noticed that xfs_btree_insrec has a bunch of debug code that return
out of the function immediately, without freeing the "new" btree cursor
that can be returned when _make_block_unfull calls xfs_btree_split. Fix
the error return in this function to free the btree cursor.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Acked-by: Anthony Iliopoulos <ailiop@suse.com>
---
fs/xfs/libxfs/xfs_btree.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 32100cfb9dfc..2eecc49fc1b2 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -3272,7 +3272,7 @@ xfs_btree_insrec(
struct xfs_btree_block *block; /* btree block */
struct xfs_buf *bp; /* buffer for block */
union xfs_btree_ptr nptr; /* new block ptr */
- struct xfs_btree_cur *ncur; /* new btree cursor */
+ struct xfs_btree_cur *ncur = NULL; /* new btree cursor */
union xfs_btree_key nkey; /* new block key */
union xfs_btree_key *lkey;
int optr; /* old key/record index */
@@ -3352,7 +3352,7 @@ xfs_btree_insrec(
#ifdef DEBUG
error = xfs_btree_check_block(cur, block, level, bp);
if (error)
- return error;
+ goto error0;
#endif
/*
@@ -3372,7 +3372,7 @@ xfs_btree_insrec(
for (i = numrecs - ptr; i >= 0; i--) {
error = xfs_btree_debug_check_ptr(cur, pp, i, level);
if (error)
- return error;
+ goto error0;
}
xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
@@ -3457,6 +3457,8 @@ xfs_btree_insrec(
return 0;
error0:
+ if (ncur)
+ xfs_btree_del_cursor(ncur, error);
return error;
}
--
2.35.3