]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
kasan: revert eviction of stack traces in generic mode
authorMarco Elver <elver@google.com>
Mon, 29 Jan 2024 10:07:02 +0000 (11:07 +0100)
committerAndrew Morton <akpm@linux-foundation.org>
Sat, 24 Feb 2024 01:27:12 +0000 (17:27 -0800)
commit711d349174fd5cf906955249dd0163635e144a1e
tree8a7e8a86280d3412cefe223013c56948209d1c42
parent31639fd6cebd4fc3687cceda14814f140c9fd95b
kasan: revert eviction of stack traces in generic mode

This partially reverts commits cc478e0b6bdf63b85ac56a6408d7c94d9635,
a414d4286f34, and 773688a6cb24 to make use of variable-sized stack depot
records, since eviction of stack entries from stack depot forces fixed-
sized stack records.  Care was taken to retain the code cleanups by the
above commits.

Eviction was added to generic KASAN as a response to alleviating the
additional memory usage from fixed-sized stack records, but this still
uses more memory than previously.

With the re-introduction of variable-sized records for stack depot, we can
just switch back to non-evictable stack records again, and return back to
the previous performance and memory usage baseline.

Before (observed after a KASAN kernel boot):

  pools: 597
  refcounted_allocations: 17547
  refcounted_frees: 6477
  refcounted_in_use: 11070
  freelist_size: 3497
  persistent_count: 12163
  persistent_bytes: 1717008

After:

  pools: 319
  refcounted_allocations: 0
  refcounted_frees: 0
  refcounted_in_use: 0
  freelist_size: 0
  persistent_count: 29397
  persistent_bytes: 5183536

As can be seen from the counters, with a generic KASAN config, refcounted
allocations and evictions are no longer used.  Due to using variable-sized
records, I observe a reduction of 278 stack depot pools (saving 4448 KiB)
with my test setup.

Link: https://lkml.kernel.org/r/20240129100708.39460-2-elver@google.com
Fixes: cc478e0b6bdf ("kasan: avoid resetting aux_lock")
Fixes: 63b85ac56a64 ("kasan: stop leaking stack trace handles")
Fixes: 08d7c94d9635 ("kasan: memset free track in qlink_free")
Fixes: a414d4286f34 ("kasan: handle concurrent kasan_record_aux_stack calls")
Fixes: 773688a6cb24 ("kasan: use stack_depot_put for Generic mode")
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/kasan/common.c
mm/kasan/generic.c
mm/kasan/kasan.h
mm/kasan/quarantine.c