rcu: tiny: Record kvfree_call_rcu() call stack for KASAN

Browse source

When running KASAN with Tiny RCU (e.g. under ARCH=um, where
a working KASAN patch is now available), we don't get any
information on the original kfree_rcu() (or similar) caller
when a problem is reported, as Tiny RCU doesn't record this.

Add the recording, which required pulling kvfree_call_rcu()
out of line for the KASAN case since the recording function
(kasan_record_aux_stack_noalloc) is neither exported, nor
can we include kasan.h into rcutiny.h.

without KASAN, the patch has no size impact (ARCH=um kernel):
    text       data         bss         dec        hex    filename
 6151515    4423154    33148520    43723189    29b29b5    linux
 6151515    4423154    33148520    43723189    29b29b5    linux + patch

with KASAN, the impact on my build was minimal:
    text       data         bss         dec        hex    filename
13915539    7388050    33282304    54585893    340ea25    linux
13911266    7392114    33282304    54585684    340e954    linux + patch
   -4273      +4064         +-0        -209

Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

...

This commit is contained in:

Johannes Berg 2022-05-27 17:07:45 +02:00 • committed by Paul E. McKenney

parent 9c9b26b0df

commit 800d6acf40

2 changed files with 24 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

11

include/linux/rcutiny.h

View file

14

kernel/rcu/tiny.c

View file