diff options
| author | Valentin Schneider | 2020-12-17 14:31:21 -0800 |
|---|---|---|
| committer | Borislav Petkov | 2021-01-11 11:43:23 +0100 |
| commit | 6d3b47ddffed70006cf4ba360eef61e9ce097d8f (patch) | |
| tree | 10e43585b7bf84f6866076eddbe72862f223c30d /arch/x86/include/asm/resctrl.h | |
| parent | e0ad6dc8969f790f14bddcfd7ea284b7e5f88a16 (diff) | |
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 'arch/x86/include/asm/resctrl.h')
| -rw-r--r-- | arch/x86/include/asm/resctrl.h | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h index 07603064df8f..d60ed0668a59 100644 --- a/arch/x86/include/asm/resctrl.h +++ b/arch/x86/include/asm/resctrl.h @@ -56,19 +56,22 @@ static void __resctrl_sched_in(void) struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state); u32 closid = state->default_closid; u32 rmid = state->default_rmid; + u32 tmp; /* * If this task has a closid/rmid assigned, use it. * Else use the closid/rmid assigned to this cpu. */ if (static_branch_likely(&rdt_alloc_enable_key)) { - if (current->closid) - closid = current->closid; + tmp = READ_ONCE(current->closid); + if (tmp) + closid = tmp; } if (static_branch_likely(&rdt_mon_enable_key)) { - if (current->rmid) - rmid = current->rmid; + tmp = READ_ONCE(current->rmid); + if (tmp) + rmid = tmp; } if (closid != state->cur_closid || rmid != state->cur_rmid) { |