From: Breno Leitao <leitao@debian.org>
To: "Liam R. Howlett (Oracle)" <liam@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
maple-tree@lists.infradead.org
Subject: Re: [PATCH v2 03/19] maple_tree: Add write lock checking with lockdep sequence numbers
Date: Wed, 8 Jul 2026 08:44:17 -0700 [thread overview]
Message-ID: <ak5v9UDuieA-dNUh@gmail.com> (raw)
In-Reply-To: <20260630190843.3563858-4-liam@infradead.org>
Hello Liam,
On Tue, Jun 30, 2026 at 03:08:27PM -0400, Liam R. Howlett (Oracle) wrote:
> +#ifdef CONFIG_RCU_STRICT_GRACE_PERIOD
> if (!mt_locked(mas->tree)) {
> if (mt_in_rcu(mas->tree))
> WARN_ON_ONCE(poll_state_synchronize_rcu(mas->rcu_gp));
Testing next-20260706 on arm64 under a stress-ng + fork/exit/mprotect workload,
I'm hitting the new maple_tree write-lock sequence check:
WARNING: lib/maple_tree.c:1188 at mas_store_prealloc+0x2a8/0xac0
It fires from several core mm paths — fork (dup_mmap), exit (exit_mmap),
and mprotect (__split_vma) — across multiple processes. The two cleanest
traces are both in the mprotect path:
WARNING: lib/maple_tree.c:1188 at mas_store_prealloc+0x2a8/0xac0, CPU#67
Call trace:
mas_store_prealloc+0x2a8/0xac0 (P)
vma_iter_store_new+0x2b4/0x3c8
vma_complete+0x258/0x7c0
__split_vma+0x64c/0x770
vma_modify+0x11fc/0x1808
vma_modify_flags+0x18c/0x220
mprotect_fixup+0x22c/0x4e8
do_mprotect_pkey+0x558/0x720
__arm64_sys_mprotect+0x88/0xa8
WARNING: lib/maple_tree.c:1188 at mas_prev+0x160/0x1a8, CPU#67
Call trace:
mas_prev+0x160/0x1a8 (P)
__split_vma+0x658/0x770
vma_modify+0x11fc/0x1808
vma_modify_flags+0x18c/0x220
mprotect_fixup+0x22c/0x4e8
do_mprotect_pkey+0x558/0x720
__arm64_sys_mprotect+0x88/0xa8
Is this a known issue?
next prev parent reply other threads:[~2026-07-08 15:44 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-30 19:08 [PATCH v2 00/19] maple_tree: lock checking and clean ups Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 01/19] maple_tree: Add rcu locking check when LOCKDEP is enabled Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 02/19] locking/lockdep: Add sequence counter to held_lock Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 03/19] maple_tree: Add write lock checking with lockdep sequence numbers Liam R. Howlett (Oracle)
2026-07-08 15:44 ` Breno Leitao [this message]
2026-06-30 19:08 ` [PATCH v2 04/19] maple_tree: Documentation fix Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 05/19] maple_tree: Drop dead code from mas_extend_spanning_null() Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 06/19] maple_tree: Drop MAPLE_ALLOC_SLOTS Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 07/19] maple_tree: Clarify comments on mas_nomem() Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 08/19] maple_tree: Use prefetched value in mas_wr_store_type() Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 09/19] maple_tree: Optimise mas_wr_node_store() when not in rcu mode Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 10/19] maple_tree: micro optimisation of mas_wr_store_type() Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 11/19] maple_tree: Add bulk parent set helper Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 12/19] maple_tree: Catch race in mas_alloc_cyclic() Liam R. Howlett (Oracle)
2026-06-30 19:41 ` Chuck Lever
2026-06-30 19:08 ` [PATCH v2 13/19] maple_tree: Document that erase may use GFP_KERNEL for allocations Liam R. Howlett (Oracle)
2026-06-30 19:32 ` Rik van Riel
2026-06-30 19:08 ` [PATCH v2 14/19] maple_tree: WARN_ON_ONCE when allocations fail Liam R. Howlett (Oracle)
2026-06-30 23:02 ` Andrew Morton
2026-06-30 19:08 ` [PATCH v2 15/19] maple_tree: Document erase and allocations better Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 16/19] maple_tree: Change two GFP flags in tests Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 17/19] maple_tree: Fix argument name in header Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 18/19] maple_tree: Avoid extra gap calculation Liam R. Howlett (Oracle)
2026-06-30 19:08 ` [PATCH v2 19/19] maple_tree: Add helper mas_make_walkable() Liam R. Howlett (Oracle)
2026-06-30 23:05 ` [PATCH v2 00/19] maple_tree: lock checking and clean ups Andrew Morton
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