linux-kernel - Re: [PATCH 7/7] mm/page_alloc: Replace local

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Date:   Wed, 15 Jun 2022 16:04:46 -0700
From:   Andrew Morton <akpm@...ux-foundation.org>
To:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Yu Zhao <yuzhao@...gle.com>
Cc:     Mel Gorman <mgorman@...hsingularity.net>,
        Nicolas Saenz Julienne <nsaenzju@...hat.com>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Michal Hocko <mhocko@...nel.org>,
        Hugh Dickins <hughd@...gle.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux-MM <linux-mm@...ck.org>
Subject: Re: [PATCH 7/7] mm/page_alloc: Replace local_lock with normal
 spinlock

On Thu, 16 Jun 2022 00:48:55 +0200 Marek Szyprowski <m.szyprowski@...sung.com> wrote:

> In the logs I see lots of errors like:
> 
> BUG: sleeping function called from invalid context at 
> ./include/linux/sched/mm.h:274
> 
> BUG: scheduling while atomic: systemd-udevd/288/0x00000002
> 
> BUG: sleeping function called from invalid context at mm/filemap.c:2647
> 
> however there are also a fatal ones like:
> 
> Unable to handle kernel paging request at virtual address 00000000017a87b4
> 
> 
> The issues seems to be a bit random. Looks like memory trashing. 
> Reverting $subject on top of current linux-next fixes all those issues.
> 
> 

This?

--- a/mm/page_alloc.c~mm-page_alloc-replace-local_lock-with-normal-spinlock-fix
+++ a/mm/page_alloc.c
@@ -183,8 +183,10 @@ static DEFINE_MUTEX(pcp_batch_high_lock)
 	type *_ret;							\
 	pcpu_task_pin();						\
 	_ret = this_cpu_ptr(ptr);					\
-	if (!spin_trylock_irqsave(&_ret->member, flags))		\
+	if (!spin_trylock_irqsave(&_ret->member, flags)) {		\
+		pcpu_task_unpin();					\
 		_ret = NULL;						\
+	}								\
 	_ret;								\
 })
 

I'll drop Mel's patch for next -next.