CVE-2026-46066

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ceph: fix num_ops off-by-one when crypto allocation fails<br /> <br /> move_dirty_folio_in_page_array() may fail if the file is encrypted, the<br /> dirty folio is not the first in the batch, and it fails to allocate a<br /> bounce buffer to hold the ciphertext. When that happens,<br /> ceph_process_folio_batch() simply redirties the folio and flushes the<br /> current batch -- it can retry that folio in a future batch.<br /> <br /> However, if this failed folio is not contiguous with the last folio that<br /> did make it into the batch, then ceph_process_folio_batch() has already<br /> incremented `ceph_wbc-&gt;num_ops`; because it doesn&amp;#39;t follow through and<br /> add the discontiguous folio to the array, ceph_submit_write() -- which<br /> expects that `ceph_wbc-&gt;num_ops` accurately reflects the number of<br /> contiguous ranges (and therefore the required number of "write extent"<br /> ops) in the writeback -- will panic the kernel:<br /> <br /> BUG_ON(ceph_wbc-&gt;op_idx + 1 != req-&gt;r_num_ops);<br /> <br /> This issue can be reproduced on affected kernels by writing to<br /> fscrypt-enabled CephFS file(s) with a 4KiB-written/4KiB-skipped/repeat<br /> pattern (total filesize should not matter) and gradually increasing the<br /> system&amp;#39;s memory pressure until a bounce buffer allocation fails.<br /> <br /> Fix this crash by decrementing `ceph_wbc-&gt;num_ops` back to the correct<br /> value when move_dirty_folio_in_page_array() fails, but the folio already<br /> started counting a new (i.e. still-empty) extent.<br /> <br /> The defect corrected by this patch has existed since 2022 (see first<br /> `Fixes:`), but another bug blocked multi-folio encrypted writeback until<br /> recently (see second `Fixes:`). The second commit made it into 6.18.16,<br /> 6.19.6, and 7.0-rc1, unmasking the panic in those versions. This patch<br /> therefore fixes a regression (panic) introduced by cac190c7674f.