Messages in this thread | | | From | "Liam R. Howlett" <> | Subject | [PATCH v2 0/2] maple_tree: Fix mas_prev() state regression. | Date | Fri, 22 Sep 2023 11:38:51 -0400 |
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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
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