The patch titled Subject: nilfs2: fix incomplete buffer cleanup in nilfs_btnode_abort_change_key() has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-fix-incomplete-buffer-cleanup-in-nilfs_btnode_abort_change_key.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Ryusuke Konishi konishi.ryusuke@gmail.com Subject: nilfs2: fix incomplete buffer cleanup in nilfs_btnode_abort_change_key() Date: Sat, 13 May 2023 19:24:28 +0900
A syzbot fault injection test reported that nilfs_btnode_create_block, a helper function that allocates a new node block for b-trees, causes a kernel BUG for disk images where the file system block size is smaller than the page size.
This was due to unexpected flags on the newly allocated buffer head, and it turned out to be because the buffer flags were not cleared by nilfs_btnode_abort_change_key() after an error occurred during a b-tree update operation and the buffer was later reused in that state.
Fix this issue by using nilfs_btnode_delete() to abandon the unused preallocated buffer in nilfs_btnode_abort_change_key().
Link: https://lkml.kernel.org/r/20230513102428.10223-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Reported-by: syzbot+b0a35a5c1f7e846d3b09@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/000000000000d1d6c205ebc4d512@google.com Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
fs/nilfs2/btnode.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
--- a/fs/nilfs2/btnode.c~nilfs2-fix-incomplete-buffer-cleanup-in-nilfs_btnode_abort_change_key +++ a/fs/nilfs2/btnode.c @@ -285,6 +285,14 @@ void nilfs_btnode_abort_change_key(struc if (nbh == NULL) { /* blocksize == pagesize */ xa_erase_irq(&btnc->i_pages, newkey); unlock_page(ctxt->bh->b_page); - } else - brelse(nbh); + } else { + /* + * When canceling a buffer that a prepare operation has + * allocated to copy a node block to another location, use + * nilfs_btnode_delete() to initialize and release the buffer + * so that the buffer flags will not be in an inconsistent + * state when it is reallocated. + */ + nilfs_btnode_delete(nbh); + } } _
Patches currently in -mm which might be from konishi.ryusuke@gmail.com are
nilfs2-fix-use-after-free-bug-of-nilfs_root-in-nilfs_evict_inode.patch nilfs2-fix-incomplete-buffer-cleanup-in-nilfs_btnode_abort_change_key.patch