[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <20230922153853.767603-1-Liam.Howlett@oracle.com>
Date: Fri, 22 Sep 2023 11:38:51 -0400
From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: maple-tree@...ts.infradead.org, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, pedro.falcato@...il.com,
stable@...nel.org, "Liam R. Howlett" <Liam.Howlett@...cle.com>
Subject: [PATCH v2 0/2] maple_tree: Fix mas_prev() state regression.
Pedro Falcato retported an mprotect regression [1] which was bisected back
to the iterator changes for maple tree. Root cause analysis showed the
mas_prev() running off the end of the VMA space (previous from 0)
followed by mas_find(), would skip the first value.
This patch set introduces maple state underflow/overflow so the sequence
of calls on the maple state will return what the user expects.
Users who encounter this bug may see mprotect(), userfaultfd_register(),
and mlock() fail on VMAs mapped with address 0.
[1] https://bugs.archlinux.org/task/79656
Liam R. Howlett (2):
maple_tree: Add mas_is_active() to detect in-tree walks
maple_tree: Add MAS_UNDERFLOW and MAS_OVERFLOW states
include/linux/maple_tree.h | 11 ++
lib/maple_tree.c | 221 +++++++++++++++++++++++++++----------
lib/test_maple_tree.c | 87 ++++++++++++---
3 files changed, 246 insertions(+), 73 deletions(-)
--
2.40.1
Powered by blists - more mailing lists