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 wb_queue_isw() queues work, we are guaranteed we have added the first item to wb->switch_wbs_ctxs and nobody is going to remove it (and drop the wb reference it holds) until the queued work runs.
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 wb_queue_isw() queues work, we are guaranteed we have added the first item to wb->switch_wbs_ctxs and nobody is going to remove it (and drop the wb reference it holds) until the queued work runs.
Update Linux/Linux to 382cf81cae89e58d22b4bdc38891cd4d0b9ba921 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanwriteback: Fix use after free in inode_switch_wbs_work_fn() affects Linux/Linux (generic), Linux/Linux (generic). Severity is high. 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 wb_queue_isw() queues work, we are guaranteed we have added the first item to wb->switch_wbs_ctxs and nobody is going to remove it (and drop the wb reference it holds) until the queued work runs.
AI coding agents often install or upgrade packages automatically in generic. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=d072b38a64ddbc2d58c2e525a24af24ecbfebcb7 <382cf81cae89e58d22b4bdc38891cd4d0b9ba921 || >=ac7b2c21f2269d815ad0cdf0f8258d55185b805c <19ec404b079be057b387643ba0c69bbcc5867c35 || >=fabfc1fcddc5d8185722d4fde5f0968c4760b71e <156cc63691c1f20905510b1007896e090355e6c2 || >=e1b849cfa6b61f1c866a908c9e8dd9b5aaab820b <028103656b84273c73e9e271cf95c9f3421f4b8a || >=e1b849cfa6b61f1c866a908c9e8dd9b5aaab820b <9223e5f30403a9b506d6d0bff4f2e29a2d7d46af || >=e1b849cfa6b61f1c866a908c9e8dd9b5aaab820b <6689f01d6740cf358932b3e97ee968c6099800d9 | 382cf81cae89e58d22b4bdc38891cd4d0b9ba921, 19ec404b079be057b387643ba0c69bbcc5867c35, 156cc63691c1f20905510b1007896e090355e6c2, 028103656b84273c73e9e271cf95c9f3421f4b8a, 9223e5f30403a9b506d6d0bff4f2e29a2d7d46af, 6689f01d6740cf358932b3e97ee968c6099800d9 |
| Linux/Linuxgeneric | 6.18 | Not reported |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by CVE List V5 (cvelist).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate Linux/Linux to 382cf81cae89e58d22b4bdc38891cd4d0b9ba921 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanwriteback: Fix use after free in inode_switch_wbs_work_fn() affects Linux/Linux (generic), Linux/Linux (generic). Severity is high. 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 wb_queue_isw() queues work, we are guaranteed we have added the first item to wb->switch_wbs_ctxs and nobody is going to remove it (and drop the wb reference it holds) until the queued work runs.
AI coding agents often install or upgrade packages automatically in generic. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=d072b38a64ddbc2d58c2e525a24af24ecbfebcb7 <382cf81cae89e58d22b4bdc38891cd4d0b9ba921 || >=ac7b2c21f2269d815ad0cdf0f8258d55185b805c <19ec404b079be057b387643ba0c69bbcc5867c35 || >=fabfc1fcddc5d8185722d4fde5f0968c4760b71e <156cc63691c1f20905510b1007896e090355e6c2 || >=e1b849cfa6b61f1c866a908c9e8dd9b5aaab820b <028103656b84273c73e9e271cf95c9f3421f4b8a || >=e1b849cfa6b61f1c866a908c9e8dd9b5aaab820b <9223e5f30403a9b506d6d0bff4f2e29a2d7d46af || >=e1b849cfa6b61f1c866a908c9e8dd9b5aaab820b <6689f01d6740cf358932b3e97ee968c6099800d9 | 382cf81cae89e58d22b4bdc38891cd4d0b9ba921, 19ec404b079be057b387643ba0c69bbcc5867c35, 156cc63691c1f20905510b1007896e090355e6c2, 028103656b84273c73e9e271cf95c9f3421f4b8a, 9223e5f30403a9b506d6d0bff4f2e29a2d7d46af, 6689f01d6740cf358932b3e97ee968c6099800d9 |
| Linux/Linuxgeneric | 6.18 | Not reported |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by CVE List V5 (cvelist).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard