From: Ben Horgan <ben.horgan@arm.com>
To: ben.horgan@arm.com
Cc: james.morse@arm.com, reinette.chatre@intel.com,
fenghuay@nvidia.com, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, dave.martin@arm.com,
andre.przywara@arm.com
Subject: [PATCH v1 10/11] arm_mpam: Don't loop forever if there is the maximum possible amount of PARTIDs
Date: Fri, 10 Jul 2026 12:55:44 +0100 [thread overview]
Message-ID: <20260710115546.29644-11-ben.horgan@arm.com> (raw)
In-Reply-To: <20260710115546.29644-1-ben.horgan@arm.com>
On a theoretical platform with the maximum possible number of usable
PARTIDs, 0XFFFF, the loops iterating over PARTID in mpam_reset_ris() and
mpam_reprogram_ris() will never reach their termination condition leading
to a system hang when register the cpu hotplug handlers when MPAM is
enabling.
Fix these loops.
Fixes: f188a36ca241 ("arm_mpam: Reset MSC controls from cpuhp callbacks")
Fixes: 09b89d2a72f3 ("arm_mpam: Allow configuration to be applied and restored during cpu online")
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
---
drivers/resctrl/mpam_devices.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index c9adc450f087..9412ffde1cf1 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1735,7 +1735,7 @@ static int mpam_save_mbwu_state(void *arg)
*/
static int mpam_reset_ris(void *arg)
{
- u16 partid, partid_max;
+ u16 partid_max;
struct mpam_config reset_cfg = {};
struct mpam_msc_ris *ris = arg;
@@ -1745,7 +1745,7 @@ static int mpam_reset_ris(void *arg)
spin_lock(&partid_max_lock);
partid_max = mpam_partid_max;
spin_unlock(&partid_max_lock);
- for (partid = 0; partid <= partid_max; partid++)
+ for (u32 partid = 0; partid <= partid_max; partid++)
mpam_reprogram_ris_partid(ris, partid, &reset_cfg);
return 0;
@@ -1792,7 +1792,6 @@ static int __write_config(void *arg)
static void mpam_reprogram_msc(struct mpam_msc *msc)
{
- u16 partid;
bool reset;
struct mpam_config *cfg;
struct mpam_msc_ris *ris;
@@ -1816,7 +1815,7 @@ static void mpam_reprogram_msc(struct mpam_msc *msc)
arg.comp = ris->vmsc->comp;
arg.ris = ris;
reset = true;
- for (partid = 0; partid <= mpam_partid_max; partid++) {
+ for (u32 partid = 0; partid <= mpam_partid_max; partid++) {
cfg = &ris->vmsc->comp->cfg[partid];
if (!bitmap_empty(cfg->features, MPAM_FEATURE_LAST))
reset = false;
--
2.43.0
next prev parent reply other threads:[~2026-07-10 11:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-10 11:55 [PATCH v1 00/11] arm_mpam: minor fixes at v7.2 Ben Horgan
2026-07-10 11:55 ` [PATCH v1 01/11] arm_mpam: Move MPAMF_ECR write helpers to allow reuse Ben Horgan
2026-07-10 11:55 ` [PATCH v1 02/11] arm_mpam: Restore the error interrupt enable from mpam_cpu_online() Ben Horgan
2026-07-10 11:55 ` [PATCH v1 03/11] arm_mpam: Set mpam_feat_msmon_mbwu_31counter when there are bandwidth counters Ben Horgan
2026-07-10 11:55 ` [PATCH v1 04/11] arm_mpam: Add missing mon_sel locking in MBWU restore Ben Horgan
2026-07-10 11:55 ` [PATCH v1 05/11] arm_mpam: Ensure MBWU counters are reset on restore Ben Horgan
2026-07-10 11:55 ` [PATCH v1 06/11] arm_mpam: Use __ris_msmon_read() for saving MBWU state Ben Horgan
2026-07-10 11:55 ` [PATCH v1 07/11] arm_mpam: Initialize all of struct mon_read in mpam_restore_mbwu_state() Ben Horgan
2026-07-10 11:55 ` [PATCH v1 08/11] arm_mpam: resctrl: Correct check that existing class is L3 Ben Horgan
2026-07-10 11:55 ` [PATCH v1 09/11] arm_mpam: resctrl: Make read_mon_cdp_safe() self consistent Ben Horgan
2026-07-10 11:55 ` Ben Horgan [this message]
2026-07-10 11:55 ` [PATCH v1 11/11] arm_mpam: Switch to kvzmalloc_objs() for allocation of component cfg Ben Horgan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260710115546.29644-11-ben.horgan@arm.com \
--to=ben.horgan@arm.com \
--cc=andre.przywara@arm.com \
--cc=dave.martin@arm.com \
--cc=fenghuay@nvidia.com \
--cc=james.morse@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=reinette.chatre@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox