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From: Andrew Morton <akpm@linux-foundation.org>
To: "Zach O'Keefe" <zokeefe@google.com>
Cc: Yang Shi <shy828301@gmail.com>,
	Ivan Orlov <ivan.orlov0322@gmail.com>,
	himadrispandya@gmail.com, linux-kernel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-mm@kvack.org, skhan@linuxfoundation.org,
	syzbot+9578faa5475acb35fa50@syzkaller.appspotmail.com,
	Mike Kravetz <mike.kravetz@oracle.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v2] mm: khugepaged: Fix kernel BUG in hpage_collapse_scan_file
Date: Sun, 16 Apr 2023 11:33:35 -0700	[thread overview]
Message-ID: <20230416113335.caeafda1328fdd4bfe2406e8@linux-foundation.org> (raw)
In-Reply-To: <CAAa6QmTLXSvygQQNk=8C4pB3D2Twy1guzo=+-aXhCqNAE3Q3MA@mail.gmail.com>


Circling back to this fix...

The BUG() is obviously real.  We're unsure that Ivan's fix is the best
one.  We haven't identified a Fixes:, and as this report is against the 6.2
kernel, a cc:stable will be needed.

According to the sysbot bisection
(https://syzkaller.appspot.com/bug?id=7d6bb3760e026ece7524500fe44fb024a0e959fc),
this is present in linux-5.19, so it might predate Zach's
58ac9a8993a13ebc changes.  But that bisection claim might be
misleading.

And Zach is offline for a few months.  So can people please take a look
and see if we can get this wrapped up?

Matthew, the assertion failure is in the

	VM_BUG_ON(index != xas.xa_index);

which was added in 77da9389b9d5f, so perhaps you could take a look?

Thanks.


  reply	other threads:[~2023-04-16 18:33 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-30 15:53 [PATCH v2] mm: khugepaged: Fix kernel BUG in hpage_collapse_scan_file Ivan Orlov
2023-03-31  1:33 ` Zach O'Keefe
2023-03-31  6:47   ` Ivan Orlov
2023-04-04  0:58   ` Yang Shi
2023-04-05 16:43     ` Zach O'Keefe
2023-04-16 18:33       ` Andrew Morton [this message]
2023-04-16 20:39         ` Ivan Orlov
2023-04-16 23:04         ` Ivan Orlov
2023-04-17  0:45         ` Hugh Dickins
2023-04-17 18:28         ` Ivan Orlov
2023-04-18 21:28           ` Andrew Morton

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