Commit 52eb7433 authored by Reinette Chatre's avatar Reinette Chatre Committed by Borislav Petkov
Browse files

x86/resctrl: Fix rdt_find_domain() return value and checks

rdt_find_domain() returns an ERR_PTR() that is generated from a provided
domain id when the value is negative.

Care needs to be taken when creating an ERR_PTR() from this value
because a subsequent check using IS_ERR() expects the error to
be within the MAX_ERRNO range. Using an invalid domain id as an
ERR_PTR() does work at this time since this is currently always -1.
Using this undocumented assumption is fragile since future users of
rdt_find_domain() may not be aware of thus assumption.

Two related issues are addressed:

- Ensure that rdt_find_domain() always returns a valid error value by
forcing the error to be -ENODEV when a negative domain id is provided.

- In a few instances the return value of rdt_find_domain() is just
checked for NULL - fix these to include a check of ERR_PTR.

Fixes: d89b7379 ("x86/intel_rdt/cqm: Add mon_data")
Fixes: 521348b0

 ("x86/intel_rdt: Introduce utility to obtain CDP peer")
Signed-off-by: default avatarReinette Chatre <>
Signed-off-by: default avatarBorislav Petkov <>
Cc: "H. Peter Anvin" <>
Cc: Ingo Molnar <>
Cc: Thomas Gleixner <>
Cc: Tony Luck <>
Cc: x86-ml <>
parent cb74635f
......@@ -454,7 +454,7 @@ struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id,
struct list_head *l;
if (id < 0)
return ERR_PTR(id);
return ERR_PTR(-ENODEV);
list_for_each(l, &r->domains) {
d = list_entry(l, struct rdt_domain, list);
......@@ -534,7 +534,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
r = &rdt_resources_all[resid];
d = rdt_find_domain(r, domid, NULL);
if (!d) {
if (IS_ERR_OR_NULL(d)) {
ret = -ENOENT;
goto out;
......@@ -1029,7 +1029,7 @@ static int rdt_cdp_peer_get(struct rdt_resource *r, struct rdt_domain *d,
* peer RDT CDP resource. Hence the WARN.
_d_cdp = rdt_find_domain(_r_cdp, d->id, NULL);
if (WARN_ON(!_d_cdp)) {
if (WARN_ON(IS_ERR_OR_NULL(_d_cdp))) {
_r_cdp = NULL;
ret = -EINVAL;
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