Commit 587edd70 authored by Tony Luck's avatar Tony Luck Committed by Borislav Petkov (AMD)
Browse files

x86/resctrl: Initialize on-stack struct rmid_read instances 



New semantics rely on some struct rmid_read members having NULL values to
distinguish between the SNC and non-SNC scenarios.  resctrl can thus no longer
rely on this struct not being initialized properly.

Initialize all on-stack declarations of struct rmid_read:

  rdtgroup_mondata_show()
  mbm_update()
  mkdir_mondata_subdir()

to ensure that garbage values from the stack are not passed down to other
functions.

  [ bp: Massage commit message. ]

Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Tested-by: default avatarBabu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20240628215619.76401-11-tony.luck@intel.com
parent fb1f51f6

arch/x86/kernel/cpu/resctrl/ctrlmondata.c

+1 −2
Original line number Diff line number Diff line
@@ -529,7 +529,6 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, 
	rr->evtid = evtid;

	rr->r = r;

	rr->d = d;

	rr->val = 0;

	rr->first = first;

	rr->arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, evtid);

	if (IS_ERR(rr->arch_mon_ctx)) {
@@ -557,12 +556,12 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) 
{

	struct kernfs_open_file *of = m->private;

	struct rdt_domain_hdr *hdr;

	struct rmid_read rr = {0};

	struct rdt_mon_domain *d;

	u32 resid, evtid, domid;

	struct rdtgroup *rdtgrp;

	struct rdt_resource *r;

	union mon_data_bits md;

	struct rmid_read rr;

	int ret = 0;



	rdtgrp = rdtgroup_kn_lock_live(of->kn);

arch/x86/kernel/cpu/resctrl/monitor.c

+1 −2
Original line number Diff line number Diff line
@@ -780,9 +780,8 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_mon_domain *dom_mbm) 
static void mbm_update(struct rdt_resource *r, struct rdt_mon_domain *d,

		       u32 closid, u32 rmid)

{

	struct rmid_read rr;

	struct rmid_read rr = {0};



	rr.first = false;

	rr.r = r;

	rr.d = d;

arch/x86/kernel/cpu/resctrl/rdtgroup.c

+1 −1
Original line number Diff line number Diff line
@@ -3029,10 +3029,10 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn, 
				struct rdt_mon_domain *d,

				struct rdt_resource *r, struct rdtgroup *prgrp)

{

	struct rmid_read rr = {0};

	union mon_data_bits priv;

	struct kernfs_node *kn;

	struct mon_evt *mevt;

	struct rmid_read rr;

	char name[32];

	int ret;