summaryrefslogtreecommitdiff
path: root/drivers/misc/lkdtm/refcount.c
diff options
context:
space:
mode:
authorJens Axboe <axboe@kernel.dk>2024-09-17 08:32:53 -0600
committerJens Axboe <axboe@kernel.dk>2024-09-17 08:32:53 -0600
commit42b16d3ac371a2fac9b6f08fd75f23f34ba3955a (patch)
treed15a2fe1f7441361b972bc787af5122adc3fcb71 /drivers/misc/lkdtm/refcount.c
parent4208c562a27899212e8046080555e0f204e0579a (diff)
parent98f7e32f20d28ec452afb208f9cffc08448a2652 (diff)
Merge tag 'v6.11' into for-6.12/block
Merge in 6.11 final to get the fix for preventing deadlocks on an elevator switch, as there's a fixup for that patch. * tag 'v6.11': (1788 commits) Linux 6.11 Revert "KVM: VMX: Always honor guest PAT on CPUs that support self-snoop" pinctrl: pinctrl-cy8c95x0: Fix regcache cifs: Fix signature miscalculation mm: avoid leaving partial pfn mappings around in error case drm/xe/client: add missing bo locking in show_meminfo() drm/xe/client: fix deadlock in show_meminfo() drm/xe/oa: Enable Xe2+ PES disaggregation drm/xe/display: fix compat IS_DISPLAY_STEP() range end drm/xe: Fix access_ok check in user_fence_create drm/xe: Fix possible UAF in guc_exec_queue_process_msg drm/xe: Remove fence check from send_tlb_invalidation drm/xe/gt: Remove double include net: netfilter: move nf flowtable bpf initialization in nf_flow_table_module_init() PCI: Fix potential deadlock in pcim_intx() workqueue: Clear worker->pool in the worker thread context net: tighten bad gso csum offset check in virtio_net_hdr netlink: specs: mptcp: fix port endianness net: dpaa: Pad packets to ETH_ZLEN mptcp: pm: Fix uaf in __timer_delete_sync ...
Diffstat (limited to 'drivers/misc/lkdtm/refcount.c')
-rw-r--r--drivers/misc/lkdtm/refcount.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/refcount.c b/drivers/misc/lkdtm/refcount.c
index 5cd488f54cfa..8f744bee6fbd 100644
--- a/drivers/misc/lkdtm/refcount.c
+++ b/drivers/misc/lkdtm/refcount.c
@@ -182,6 +182,21 @@ static void lkdtm_REFCOUNT_SUB_AND_TEST_NEGATIVE(void)
check_negative(&neg, 3);
}
+/*
+ * A refcount_sub_and_test() by zero when the counter is at zero should act like
+ * refcount_sub_and_test() above when going negative.
+ */
+static void lkdtm_REFCOUNT_SUB_AND_TEST_ZERO(void)
+{
+ refcount_t neg = REFCOUNT_INIT(0);
+
+ pr_info("attempting bad refcount_sub_and_test() at zero\n");
+ if (refcount_sub_and_test(0, &neg))
+ pr_warn("Weird: refcount_sub_and_test() reported zero\n");
+
+ check_negative(&neg, 0);
+}
+
static void check_from_zero(refcount_t *ref)
{
switch (refcount_read(ref)) {
@@ -400,6 +415,7 @@ static struct crashtype crashtypes[] = {
CRASHTYPE(REFCOUNT_DEC_NEGATIVE),
CRASHTYPE(REFCOUNT_DEC_AND_TEST_NEGATIVE),
CRASHTYPE(REFCOUNT_SUB_AND_TEST_NEGATIVE),
+ CRASHTYPE(REFCOUNT_SUB_AND_TEST_ZERO),
CRASHTYPE(REFCOUNT_INC_ZERO),
CRASHTYPE(REFCOUNT_ADD_ZERO),
CRASHTYPE(REFCOUNT_INC_SATURATED),