The patch titled
Subject: mm: multi-gen LRU: move lru_gen_add_mm() out of IRQ-off region
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-multi-gen-lru-move-lru_gen_add_mm-out-of-irq-off-region.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-multi-gen-lru-move-lru_gen_add_mm-out-of-irq-off-region.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Subject: mm: multi-gen LRU: move lru_gen_add_mm() out of IRQ-off region
Date: Wed, 26 Oct 2022 15:48:30 +0200
lru_gen_add_mm() has been added within an IRQ-off region in the commit
mentioned below. The other invocations of lru_gen_add_mm() are not within
an IRQ-off region.
The invocation within IRQ-off region is problematic on PREEMPT_RT because
the function is using a spin_lock_t which must not be used within
IRQ-disabled regions.
The other invocations of lru_gen_add_mm() occur while
task_struct::alloc_lock is acquired. Move lru_gen_add_mm() after
interrupts are enabled and before task_unlock().
Link: https://lkml.kernel.org/r/20221026134830.711887-1-bigeasy@xxxxxxxxxxxxx
Fixes: bd74fdaea1460 ("mm: multi-gen LRU: support page table walks")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Acked-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: "Eric W . Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/fs/exec.c~mm-multi-gen-lru-move-lru_gen_add_mm-out-of-irq-off-region
+++ a/fs/exec.c
@@ -1012,7 +1012,6 @@ static int exec_mmap(struct mm_struct *m
active_mm = tsk->active_mm;
tsk->active_mm = mm;
tsk->mm = mm;
- lru_gen_add_mm(mm);
/*
* This prevents preemption while active_mm is being loaded and
* it and mm are being updated, which could cause problems for
@@ -1025,6 +1024,7 @@ static int exec_mmap(struct mm_struct *m
activate_mm(active_mm, mm);
if (IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
local_irq_enable();
+ lru_gen_add_mm(mm);
task_unlock(tsk);
lru_gen_use_mm(mm);
if (old_mm) {
_
Patches currently in -mm which might be from bigeasy@xxxxxxxxxxxxx are
mm-multi-gen-lru-move-lru_gen_add_mm-out-of-irq-off-region.patch
