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From: Philip Li <philip.li@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: kernel test robot <lkp@intel.com>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Chinwen Chang <chinwen.chang@mediatek.com>
Subject: Re: [linux-next:master] BUILD REGRESSION 605cbf3d5f20470ec303b79feda3202935f4a142
Date: Sun, 23 Aug 2020 11:41:05 +0800	[thread overview]
Message-ID: <20200823034105.GA2953@intel.com> (raw)
In-Reply-To: <20200820134305.baa5ac2c1300a6b412a0c7c9@linux-foundation.org>

On Thu, Aug 20, 2020 at 01:43:05PM -0700, Andrew Morton wrote:
> On Fri, 21 Aug 2020 04:26:12 +0800 kernel test robot <lkp@intel.com> wrote:
> 
> > tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git  master
> > branch HEAD: 605cbf3d5f20470ec303b79feda3202935f4a142  Add linux-next specific files for 20200820
> > 
> > Error/Warning in current branch:
> 
> > ...
> >
> > 
> > fs/proc/task_mmu.c:947 show_smaps_rollup() error: double unlocked 'mm->mmap_lock' (orig line 879)
> 
> This is code added by "mm: proc: smaps_rollup: do not stall write
> attempts on mmap_lock"
> (http://lkml.kernel.org/r/1597715898-3854-4-git-send-email-chinwen.chang@mediatek.com).
> 
> I don't get it.
Sorry Andrew, this is a false positive. We wrongly send out a few false reports
related to "double unlocked" due to bot issue. Sorry for the inconvenience caused.

> 
> : 		if (mmap_lock_is_contended(mm)) {
> : 			mmap_read_unlock(mm);
> : 			ret = mmap_read_lock_killable(mm);
> : 			if (ret) {
> : 				release_task_mempolicy(priv);
> : 				goto out_put_mm;
> : 			}
> 
> Here the mmap_lock is again taken for read
> 
> :		...
> :
> : 		}
> : 		/* Case 2 above */
> : 		vma = vma->vm_next;
> : 	}
> : 
> : 	...
> :
> : 	mmap_read_unlock(mm);
> 
> and here it's unlocked.  I don't see a possibility for double-unlock?
> 


      reply	other threads:[~2020-08-23  3:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-20 20:26 [linux-next:master] BUILD REGRESSION 605cbf3d5f20470ec303b79feda3202935f4a142 kernel test robot
2020-08-20 20:40 ` Andrew Morton
2020-08-20 21:03   ` Amir Goldstein
2020-08-20 20:43 ` Andrew Morton
2020-08-23  3:41   ` Philip Li [this message]

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