The patch below does not apply to the 6.5-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.5.y git checkout FETCH_HEAD git cherry-pick -x 5c590804b6b0ff933ed4e5cee5d76de3a5048d9f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023100439-obtuse-unchain-b580@gregkh' --subject-prefix 'PATCH 6.5.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 5c590804b6b0ff933ed4e5cee5d76de3a5048d9f Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> Date: Thu, 21 Sep 2023 14:12:35 -0400 Subject: [PATCH] maple_tree: add mas_is_active() to detect in-tree walks 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> diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h index e41c70ac7744..f66f5f78f8cf 100644 --- a/include/linux/maple_tree.h +++ b/include/linux/maple_tree.h @@ -511,6 +511,15 @@ static inline bool mas_is_paused(const 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.
