CVE-2024-27005

In the Linux kernel, the following vulnerability has been resolved:

interconnect: Dont access req_list while its being manipulated

The icc_lock mutex was split into separate icc_lock and icc_bw_lock mutexes in [1] to avoid lockdep splats. However, this didnt adequately protect access to icc_node::req_list.

The icc_set_bw() function will eventually iterate over req_list while only holding icc_bw_lock, but req_list can be modified while only holding icc_lock. This causes races between icc_set_bw(), of_icc_get(), and icc_put().

Example A:

CPU0 CPU1

icc_set_bw(path_a) mutex_lock(&icc_bw_lock); icc_put(path_b) mutex_lock(&icc_lock); aggregate_requests() hlist_for_each_entry(r, … hlist_del(… <r = invalid pointer>

Example B:

CPU0 CPU1

icc_set_bw(path_a) mutex_lock(&icc_bw_lock); path_b = of_icc_get() of_icc_get_by_index() mutex_lock(&icc_lock); path_find() path_init() aggregate_requests() hlist_for_each_entry(r, … hlist_add_head(… <r = invalid pointer>

Fix this by ensuring icc_bw_lock is always held before manipulating icc_node::req_list. The additional places icc_bw_lock is held dont perform any memory allocations, so we should still be safe from the original lockdep splats that motivated the separate locks.

[1] commit af42269c3523 (interconnect: Fix locking for runpm vs reclaim)

Affected Software

References

• https://git.kernel.org/stable/c/4c65507121ea8e0b47fae6d2049c8688390d46b6
• https://git.kernel.org/stable/c/d0d04efa2e367921654b5106cc5c05e3757c2b42
• https://git.kernel.org/stable/c/de1bf25b6d771abdb52d43546cf57ad775fb68a1