The patch titled Subject: maple_tree: fix mas_prev() state separation code has been added to the -mm mm-unstable branch. Its filename is maple_tree-separate-ma_state-node-from-status-fix.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-separate-ma_state-node-from-status-fix.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> Subject: maple_tree: fix mas_prev() state separation code Date: Thu, 7 Dec 2023 14:33:19 -0500 mas_prev() was setting the ma_underflow condition when the limit was reached and not when the limit was attempting to go lower. This resulted in the incorrect behaviour on subsequent actions. This commit fixes the status setting to only set ma_underflow when the lower limit is attempted to be decremented, and modifies the testing to ensure that's the case. Link: https://lkml.kernel.org/r/20231207193319.4025462-1-Liam.Howlett@xxxxxxxxxx Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Cc: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/maple_tree.c | 16 ++++++++++++---- lib/test_maple_tree.c | 9 +++++++-- 2 files changed, 19 insertions(+), 6 deletions(-) --- a/lib/maple_tree.c~maple_tree-separate-ma_state-node-from-status-fix +++ a/lib/maple_tree.c @@ -4498,6 +4498,9 @@ again: mas->last = mas->index - 1; mas->index = mas_safe_min(mas, pivots, mas->offset); } else { + if (mas->index <= min) + goto underflow; + if (mas_prev_node(mas, min)) { mas_rewalk(mas, save_point); goto retry; @@ -4518,15 +4521,15 @@ again: if (unlikely(mas_rewalk_if_dead(mas, node, save_point))) goto retry; - if (mas->index <= min) - mas->status = ma_underflow; if (likely(entry)) return entry; if (!empty) { - if (mas_is_underflow(mas)) + if (mas->index <= min) { + mas->status = ma_underflow; return NULL; + } goto again; } @@ -4662,7 +4665,7 @@ retry: if (unlikely(mas_rewalk_if_dead(mas, node, save_point))) goto retry; - if (pivot >= max) { + if (pivot >= max) { /* Was at the limit, next will extend beyond */ mas->status = ma_overflow; return NULL; } @@ -4677,6 +4680,11 @@ again: else mas->last = mas->max; } else { + if (mas->last >= max) { + mas->status = ma_overflow; + return NULL; + } + if (mas_next_node(mas, node, max)) { mas_rewalk(mas, save_point); goto retry; --- a/lib/test_maple_tree.c~maple_tree-separate-ma_state-node-from-status-fix +++ a/lib/test_maple_tree.c @@ -3280,8 +3280,8 @@ static noinline void __init check_state_ MT_BUG_ON(mt, mas.last != 0x1500); MT_BUG_ON(mt, !mas_is_active(&mas)); - /* next:active ->active */ - entry = mas_next(&mas, ULONG_MAX); + /* next:active ->active (spanning limit) */ + entry = mas_next(&mas, 0x2100); MT_BUG_ON(mt, entry != ptr2); MT_BUG_ON(mt, mas.index != 0x2000); MT_BUG_ON(mt, mas.last != 0x2500); @@ -3346,6 +3346,11 @@ static noinline void __init check_state_ MT_BUG_ON(mt, entry != ptr); MT_BUG_ON(mt, mas.index != 0x1000); MT_BUG_ON(mt, mas.last != 0x1500); + MT_BUG_ON(mt, !mas_is_active(&mas)); /* spanning limit */ + entry = mas_prev(&mas, 0x1200); /* underflow */ + MT_BUG_ON(mt, entry != NULL); + MT_BUG_ON(mt, mas.index != 0x1000); + MT_BUG_ON(mt, mas.last != 0x1500); MT_BUG_ON(mt, !mas_is_underflow(&mas)); /* prev:underflow -> underflow (lower limit) spanning end range */ _ Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are maple_tree-remove-unnecessary-default-labels-from-switch-statements.patch maple_tree-make-mas_erase-more-robust.patch maple_tree-move-debug-check-to-__mas_set_range.patch maple_tree-add-end-of-node-tracking-to-the-maple-state.patch maple_tree-use-cached-node-end-in-mas_next.patch maple_tree-use-cached-node-end-in-mas_destroy.patch maple_tree-clean-up-inlines-for-some-functions.patch maple_tree-separate-ma_state-node-from-status.patch maple_tree-separate-ma_state-node-from-status-fix-1.patch maple_tree-separate-ma_state-node-from-status-fix-2.patch maple_tree-separate-ma_state-node-from-status-fix.patch maple_tree-remove-mas_searchable.patch maple_tree-use-maple-state-end-for-write-operations.patch maple_tree-dont-find-node-end-in-mtree_lookup_walk.patch maple_tree-mtree_range_walk-clean-up.patch