diff options
| author |   Valentin Schneider <valentin.schneider@arm.com> | 2020-12-17 14:31:21 -0800 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2021-01-11 11:43:23 +0100 |
| commit | 6d3b47ddffed70006cf4ba360eef61e9ce097d8f (patch) | |
| tree | 10e43585b7bf84f6866076eddbe72862f223c30d /arch/x86/kernel/cpu/resctrl/rdtgroup.c | |
| parent | x86/resctrl: Use task_curr() instead of task_struct->on_cpu to prevent unnecessary IPI (diff) | |
| download | linux-dev-6d3b47ddffed70006cf4ba360eef61e9ce097d8f.tar.xz linux-dev-6d3b47ddffed70006cf4ba360eef61e9ce097d8f.zip | |
x86/resctrl: Apply READ_ONCE/WRITE_ONCE to task_struct.{rmid,closid}
A CPU's current task can have its {closid, rmid} fields read locally
while they are being concurrently written to from another CPU.
This can happen anytime __resctrl_sched_in() races with either
__rdtgroup_move_task() or rdt_move_group_tasks().
Prevent load / store tearing for those accesses by giving them the
READ_ONCE() / WRITE_ONCE() treatment.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/9921fda88ad81afb9885b517fbe864a2bc7c35a9.1608243147.git.reinette.chatre@intel.com
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/rdtgroup.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index 37f37dfb52b8..f9190adc52cb 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -563,11 +563,11 @@ static int __rdtgroup_move_task(struct task_struct *tsk, */ if (rdtgrp->type == RDTCTRL_GROUP) { - tsk->closid = rdtgrp->closid; - tsk->rmid = rdtgrp->mon.rmid; + WRITE_ONCE(tsk->closid, rdtgrp->closid); + WRITE_ONCE(tsk->rmid, rdtgrp->mon.rmid); } else if (rdtgrp->type == RDTMON_GROUP) { if (rdtgrp->mon.parent->closid == tsk->closid) { - tsk->rmid = rdtgrp->mon.rmid; + WRITE_ONCE(tsk->rmid, rdtgrp->mon.rmid); } else { rdt_last_cmd_puts("Can't move task to different control group\n"); return -EINVAL; @@ -2310,8 +2310,8 @@ static void rdt_move_group_tasks(struct rdtgroup *from, struct rdtgroup *to, for_each_process_thread(p, t) { if (!from || is_closid_match(t, from) || is_rmid_match(t, from)) { - t->closid = to->closid; - t->rmid = to->mon.rmid; + WRITE_ONCE(t->closid, to->closid); + WRITE_ONCE(t->rmid, to->mon.rmid); /* * If the task is on a CPU, set the CPU in the mask. |