CVE-2026-31703
In the Linux kernel, the following vulnerability has been resolved: writeback: Fix use after free in inode_switch_wbs_work_fn() inode_switch_wbs_work_fn() has a loop like: wb_get(new_wb); while (1) { list = llist_del_all(&new_wb->switch_wbs_ctxs); /* Nothing to do? */ if (!list) break; ... process the items ... } Now adding of items to the list looks like: wb_queue_isw() if (llist_add(&isw->list, &wb->switch_wbs_ctxs)) queue_work(isw_wq, &wb->switch_work); Because inode_switch_wbs_work_fn() loops when processing isw items, it can happen that wb->switch_work is pending while wb->switch_wbs_ctxs is empty. This is a problem because in that case wb can get freed (no isw items -> no wb reference) while the work is still pending causing use-after-free issues. We cannot just fix this by cancelling work when freeing wb because that could still trigger problematic 0 -> 1 transitions on wb refcount due to wb_get() in inode_switch_wbs_work_fn(). It could be all handled with more careful code but that seems unnecessarily complex so let's avoid that until it is proven that the looping actually brings practical benefit. Just remove the loop from inode_switch_wbs_work_fn() instead. That way when
Zwakheid
In the Linux kernel, the following vulnerability has been resolved: writeback: Fix use after free in inode_switch_wbs_work_fn() inode_switch_wbs_work_fn() has a loop like: wb_get(new_wb); while (1) { list = llist_del_all(&new_wb->switch_wbs_ctxs); /* Nothing to do? */ if (!list) break; ... process the items ... } Now adding of items to the list looks like: wb_queue_isw() if (llist_add(&isw->list, &wb->switch_wbs_ctxs)) queue_work(isw_wq, &wb->switch_work); Because inode_switch_wbs_work_fn() loops when processing isw items, it can happen that wb->switch_work is pending while wb->switch_wbs_ctxs is empty. This is a problem because in that case wb can get freed (no isw items -> no wb reference) while the work is still pending causing use-after-free issues. We cannot just fix this by cancelling work when freeing wb because that could still trigger problematic 0 -> 1 transitions on wb refcount due to wb_get() in inode_switch_wbs_work_fn(). It could be all handled with more careful code but that seems unnecessarily complex so let's avoid that until it is proven that the looping actually brings practical benefit. Just remove the loop from inode_switch_wbs_work_fn() instead. That way when
Getroffen producten
- linux linux_kernel
Bronnen
- https://git.kernel.org/stable/c/028103656b84273c73e9e271cf95c9f3421f4b8a
- https://git.kernel.org/stable/c/156cc63691c1f20905510b1007896e090355e6c2
- https://git.kernel.org/stable/c/19ec404b079be057b387643ba0c69bbcc5867c35
- https://git.kernel.org/stable/c/382cf81cae89e58d22b4bdc38891cd4d0b9ba921
- https://git.kernel.org/stable/c/6689f01d6740cf358932b3e97ee968c6099800d9
- https://git.kernel.org/stable/c/9223e5f30403a9b506d6d0bff4f2e29a2d7d46af
Vind de bug voordat een aanvaller dat doet.
Log in met GitHub en start je eerste audit binnen een minuut. Voor het gratis abonnement is geen creditcard nodig.