This is a note to let you know that I've just added the patch titled
maple_tree: add mas_is_active() to detect in-tree walks
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
maple_tree-add-mas_is_active-to-detect-in-tree-walks.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 562b1f633915512df826243cd52eeb774147186c
Author: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Date: Thu Sep 21 14:12:35 2023 -0400
maple_tree: add mas_is_active() to detect in-tree walks
[ Upstream commit 5c590804b6b0ff933ed4e5cee5d76de3a5048d9f ]
Patch series "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 patchset 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.
This patch (of 2):
Instead of constantly checking each possibility of the maple state,
create a fast path that will skip over checking unlikely states.
Link: https://lkml.kernel.org/r/20230921181236.509072-1-Liam.Howlett@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20230921181236.509072-2-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Pedro Falcato <pedro.falcato@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index 443dec917ec64..27864178d1918 100644
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -488,6 +488,15 @@ static inline bool mas_is_paused(struct ma_state *mas)
return mas->node == MAS_PAUSE;
}
+/* Check if the mas is pointing to a node or not */
+static inline bool mas_is_active(struct ma_state *mas)
+{
+ if ((unsigned long)mas->node >= MAPLE_RESERVED_RANGE)
+ return true;
+
+ return false;
+}
+
/**
* mas_reset() - Reset a Maple Tree operation state.
* @mas: Maple Tree operation state.
