If `locked_pages` is zero, the page array must not be allocated: ceph_process_folio_batch() uses `locked_pages` to decide when to allocate `pages`, and redundant allocations trigger ceph_allocate_page_array()'s BUG_ON(), resulting in a worker oops (and writeback stall) or even a kernel panic. Consequently, the main loop in ceph_writepages_start() assumes that the lifetime of `pages` is confined to a single iteration.
The ceph_submit_write() function claims ownership of the page array on success. But failures only redirty/unlock the pages and fail to free the array, making the failure case in ceph_submit_write() fatal.
Free the page array (and reset locked_pages) in ceph_submit_write()'s error-handling 'if' block so that the caller's invariant (that the array does not outlive the iteration) is maintained unconditionally, making failures in ceph_submit_write() recoverable as originally intended.
Fixes: 1551ec61dc55 ("ceph: introduce ceph_submit_write() method") Cc: stable@vger.kernel.org Signed-off-by: Sam Edwards CFSworks@gmail.com --- fs/ceph/addr.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 2b722916fb9b..467aa7242b49 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -1466,6 +1466,14 @@ int ceph_submit_write(struct address_space *mapping, unlock_page(page); }
+ if (ceph_wbc->from_pool) { + mempool_free(ceph_wbc->pages, ceph_wb_pagevec_pool); + ceph_wbc->from_pool = false; + } else + kfree(ceph_wbc->pages); + ceph_wbc->pages = NULL; + ceph_wbc->locked_pages = 0; + ceph_osdc_put_request(req); return -EIO; }