4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
commit d47924417319e3b6a728c0b690f183e75bc2a702 upstream.
intel_rdt_iffline_cpu() -> domain_remove_cpu() frees memory first and then
proceeds accessing it.
BUG: KASAN: use-after-free in find_first_bit+0x1f/0x80
Read of size 8 at addr ffff883ff7c1e780 by task cpuhp/31/195
find_first_bit+0x1f/0x80
has_busy_rmid+0x47/0x70
intel_rdt_offline_cpu+0x4b4/0x510
Freed by task 195:
kfree+0x94/0x1a0
intel_rdt_offline_cpu+0x17d/0x510
Do the teardown first and then free memory.
Fixes: 24247aeeabe9 ("x86/intel_rdt/cqm: Improve limbo list processing")
Reported-by: Joseph Salisbury <joseph.salisbury@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ravi Shankar <ravi.v.shankar@xxxxxxxxx>
Cc: Peter Zilstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Vikas Shivappa <vikas.shivappa@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: "Roderick W. Smith" <rod.smith@xxxxxxxxxxxxx>
Cc: 1733662@xxxxxxxxxxxxxxxxxx
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801161957510.2366@nanos
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/intel_rdt.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -525,10 +525,6 @@ static void domain_remove_cpu(int cpu, s
*/
if (static_branch_unlikely(&rdt_mon_enable_key))
rmdir_mondata_subdir_allrdtgrp(r, d->id);
- kfree(d->ctrl_val);
- kfree(d->rmid_busy_llc);
- kfree(d->mbm_total);
- kfree(d->mbm_local);
list_del(&d->list);
if (is_mbm_enabled())
cancel_delayed_work(&d->mbm_over);
@@ -545,6 +541,10 @@ static void domain_remove_cpu(int cpu, s
cancel_delayed_work(&d->cqm_limbo);
}
+ kfree(d->ctrl_val);
+ kfree(d->rmid_busy_llc);
+ kfree(d->mbm_total);
+ kfree(d->mbm_local);
kfree(d);
return;
}