Commit-ID: d47924417319e3b6a728c0b690f183e75bc2a702
Gitweb: https://git.kernel.org/tip/d47924417319e3b6a728c0b690f183e75bc2a702
Author: Thomas Gleixner <[email protected]>
AuthorDate: Tue, 16 Jan 2018 19:59:59 +0100
Committer: Thomas Gleixner <[email protected]>
CommitDate: Wed, 17 Jan 2018 11:56:47 +0100
x86/intel_rdt/cqm: Prevent use after free
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 <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Ravi Shankar <[email protected]>
Cc: Peter Zilstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Vikas Shivappa <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: "Roderick W. Smith" <[email protected]>
Cc: [email protected]
Cc: Fenghua Yu <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801161957510.2366@nanos
---
arch/x86/kernel/cpu/intel_rdt.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 88dcf84..9944237 100644
--- 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, struct rdt_resource
*r)
*/
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, struct rdt_resource
*r)
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;
}
