In the Linux kernel, the following vulnerability has been resolved:
interconnect: Don’t access req_list while it’s 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 didn’t 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 don’t
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”)
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/interconnect/core.c"
],
"versions": [
{
"version": "af42269c3523",
"lessThan": "d0d04efa2e36",
"status": "affected",
"versionType": "git"
},
{
"version": "af42269c3523",
"lessThan": "4c65507121ea",
"status": "affected",
"versionType": "git"
},
{
"version": "af42269c3523",
"lessThan": "de1bf25b6d77",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/interconnect/core.c"
],
"versions": [
{
"version": "6.6",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.6",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.6.29",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.8.8",
"lessThanOrEqual": "6.8.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.9",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]