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Mon, 11 Jul 2022 20:46:59 +0000 Date: Mon, 11 Jul 2022 21:46:59 +0100 From: Matthew Wilcox To: Andrew Morton Cc: syzbot , linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, Zach O'Keefe , Yang Shi , Liam Howlett Subject: Re: [syzbot] memory leak in xas_create Message-ID: References: <000000000000eb2d6c05e35a0d73@google.com> <20220711133808.d86400ce9960febcb0fd537b@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220711133808.d86400ce9960febcb0fd537b@linux-foundation.org> ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=RENKm906; dmarc=none; spf=none (imf27.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657572429; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=XrLdqfPwURSj69Ep14KJAkiXrmXt6ijJ4MRJWNKc45s=; b=Ax1jQHHw7JofoyVSgcRtRxbvTBUeImmhxj/RfDFW3VIflShjq03Ftb+/rlJSh2i/3DQgvA KgvldOL27Q3cJAkS+2M+nGMeFZ3ur5pGF9njcX45pRv5W7e2thCBLpPKUU8HG2N29fmJJQ adoZsR8JHPj8dFaf+Y8hUpYLSaw443I= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657572429; a=rsa-sha256; cv=none; b=YF0EgEsdv5EdNLNB8xdyGQgsCTRlImo/PXjCRhYNlBlWKhhGb9EYy8vSkCUca1g0Jt56vL B1LFs2thGI5TAQ1iLVRw4VJzbkpHMG448Acv9sFPIj42wRhwLjM76OEv4RDytdy2aD4v5s gdrdqymwT17uscYhl9nBLdj22kdu5hk= X-Stat-Signature: t4ad5yqhoskbph8hux6ybocf3f1w4tsw X-Rspamd-Queue-Id: EB16240070 Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=RENKm906; dmarc=none; spf=none (imf27.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1657572427-865190 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jul 11, 2022 at 01:38:08PM -0700, Andrew Morton wrote: > On Sat, 09 Jul 2022 00:13:23 -0700 syzbot wrote: > > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: c1084b6c5620 Merge tag 'soc-fixes-5.19-2' of git://git.ker.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=14967ccc080000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=916233b7694a38ff > > dashboard link: https://syzkaller.appspot.com/bug?extid=a785d07959bc94837d51 > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=122ae834080000 > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+a785d07959bc94837d51@syzkaller.appspotmail.com > > > > 2022/07/05 05:22:17 executed programs: 828 > > 2022/07/05 05:22:23 executed programs: 846 > > 2022/07/05 05:22:30 executed programs: 866 > > 2022/07/05 05:22:37 executed programs: 875 > > BUG: memory leak > > Thanks. Presumably due to khugepaged changes. Huh, I was expecting it to be something I'd messed up. I've been looking at it today, but no luck figuring it out so far. > Can we expect a bisection search? We only have a syz reproducer so far, and if I understand correctly, it's probably because this is a flaky test (because it's trying to find something that's a race condition). I expect a bisection search to go badly wrong if this is true.