From: Pasha Tatashin <pasha.tatashin@soleen.com>
To: pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-m68k@lists.linux-m68k.org,
anshuman.khandual@arm.com, willy@infradead.org,
akpm@linux-foundation.org, william.kucharski@oracle.com,
mike.kravetz@oracle.com, vbabka@suse.cz, geert@linux-m68k.org,
schmitzmic@gmail.com, rostedt@goodmis.org, mingo@redhat.com,
hannes@cmpxchg.org, guro@fb.com, songmuchun@bytedance.com,
weixugc@google.com, gthelen@google.com, rientjes@google.com,
pjt@google.com
Subject: [RFC v2 00/10] Hardening page _refcount
Date: Wed, 17 Nov 2021 01:20:49 +0000 [thread overview]
Message-ID: <20211117012059.141450-1-pasha.tatashin@soleen.com> (raw)
From: Pasha Tatashin <tatashin@google.com>
Changelog:
- use the "fetch" variant instead of "return" of atomic instructions
- allow negative values, as we are using all 32-bits of _refcount.
It is hard to root cause _refcount problems, because they usually
manifest after the damage has occurred. Yet, they can lead to
catastrophic failures such memory corruptions. There were a number
of refcount related issues discovered recently [1], [2], [3].
Improve debugability by adding more checks that ensure that
page->_refcount never turns negative (i.e. double free does not
happen, or free after freeze etc).
- Check for overflow and underflow right from the functions that
modify _refcount
- Remove set_page_count(), so we do not unconditionally overwrite
_refcount with an unrestrained value
- Trace return values in all functions that modify _refcount
Applies against next-20211116.
Previous verions:
RFCv1: https://lore.kernel.org/all/20211026173822.502506-1-pasha.tatashin@soleen.com
[1] https://lore.kernel.org/all/xr9335nxwc5y.fsf@gthelen2.svl.corp.google.com
[2] https://lore.kernel.org/all/1582661774-30925-2-git-send-email-akaher@vmware.com
[3] https://lore.kernel.org/all/20210622021423.154662-3-mike.kravetz@oracle.com
Pasha Tatashin (10):
mm: page_ref_add_unless() does not trace 'u' argument
mm: add overflow and underflow checks for page->_refcount
mm: Avoid using set_page_count() in set_page_recounted()
mm: remove set_page_count() from page_frag_alloc_align
mm: avoid using set_page_count() when pages are freed into allocator
mm: rename init_page_count() -> page_ref_init()
mm: remove set_page_count()
mm: simplify page_ref_* functions
mm: do not use atomic_set_release in page_ref_unfreeze()
mm: use atomic_cmpxchg_acquire in page_ref_freeze().
arch/m68k/mm/motorola.c | 2 +-
include/linux/mm.h | 2 +-
include/linux/page_ref.h | 159 +++++++++++++++-----------------
include/trace/events/page_ref.h | 99 +++++++++++++++-----
mm/debug_page_ref.c | 30 ++----
mm/internal.h | 6 +-
mm/page_alloc.c | 19 ++--
7 files changed, 180 insertions(+), 137 deletions(-)
--
2.34.0.rc1.387.gb447b232ab-goog
next reply other threads:[~2021-11-17 1:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 1:20 Pasha Tatashin [this message]
2021-11-17 1:20 ` [RFC v2 01/10] mm: page_ref_add_unless() does not trace 'u' argument Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 02/10] mm: add overflow and underflow checks for page->_refcount Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 03/10] mm: Avoid using set_page_count() in set_page_recounted() Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 04/10] mm: remove set_page_count() from page_frag_alloc_align Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 05/10] mm: avoid using set_page_count() when pages are freed into allocator Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 06/10] mm: rename init_page_count() -> page_ref_init() Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 07/10] mm: remove set_page_count() Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 08/10] mm: simplify page_ref_* functions Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 09/10] mm: do not use atomic_set_release in page_ref_unfreeze() Pasha Tatashin
2021-11-17 1:20 ` [RFC v2 10/10] mm: use atomic_cmpxchg_acquire in page_ref_freeze() Pasha Tatashin
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