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dkim=pass header.d=linutronix.de header.s=2020e header.b=m0EJq6Q3; spf=pass (imf19.hostedemail.com: domain of tglx@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=tglx@linutronix.de; dmarc=pass (policy=none) header.from=linutronix.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1716503569; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=gcwhKwWiYkkvnly8C5LXaEQL7Q16QzdORDIjhnOhuyM=; b=C3aXfMJz2q0ljiNnOFdjDxTiuSjn1yiJSPboCjXkIHVSV8IEL8ANBKg2/CN+1g4LXBF5ie xizQ4YJzuLfVg4Cf7gjKGy7i+NAfPhzURM+8W9Uk/D6eFTJutvsjcPMhNz5MyTkCICVQAL svlZPnhNUPGf44Ha5QyeSYHVZsVvIPc= From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1716503566; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gcwhKwWiYkkvnly8C5LXaEQL7Q16QzdORDIjhnOhuyM=; b=gq3kyfpzkAMxNlWrSXHiO/lJ0kdC4Wi4ESKWucqD/5LEu5xs+wMsAZtX8mLDA9pfBJNGZy a2mRjuKBHte7t8StGqHF9Fk+kPTY7r8I3Cf0dFjcL/FUjRD9xjXqj6N0FDOIw3IFb4EsTt N2T26nbNuYx7iKRIDnGteZDvRkl2duANvHAVsoTTHRDkW4bl+adzkQwFEd0/+i2DA2swn9 0o+V4UgstK2eMM2DDBYIutQeltqqS9keNW5DONP42RqIIIwhRzkJEt/Nvx1uKDp+MKhh3G n9Q11MNbx/rtJ0lEwzwkJy9HVmjTa20j62/586hAVX/qJ3Wn1wPxBm6emGokVQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1716503566; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gcwhKwWiYkkvnly8C5LXaEQL7Q16QzdORDIjhnOhuyM=; b=m0EJq6Q3Bv+wtnC9MmrXKCodOcybz7kUd9Oz53glx+aoR1LP39QA2EAtMmnXBwuSIjXCtm AiCAbqN8xkwFAtAA== To: Vlastimil Babka , syzbot , bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, syzkaller-bugs@googlegroups.com, x86@kernel.org, linux-mm@kvack.org, Sebastian Andrzej Siewior , Tejun Heo , Lai Jiangshan Subject: Re: [syzbot] [kernel?] WARNING in flush_cpu_slab In-Reply-To: <2149ee23-5321-4422-808f-e6a9046662fc@suse.cz> References: <0000000000008c9d27061915ca9c@google.com> <87v834g6hn.ffs@tglx> <2149ee23-5321-4422-808f-e6a9046662fc@suse.cz> Date: Fri, 24 May 2024 00:32:45 +0200 Message-ID: <87r0dsdur6.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: 646631A0017 X-Rspam-User: X-Rspamd-Server: rspam12 X-Stat-Signature: 5n58j8777oydtrh56q7n4wwnzu3bgzsu X-HE-Tag: 1716503569-971587 X-HE-Meta: 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 7pV8mTY+ 39/xeTItY93swqcJQwHTfP7mfSJdos1+ExPnyziDVTBRFBYQwzh9idMsY9p1qJRcsGHuOUZ5xtIoMk8Vck4+z3/EPgyHyxOPMjfiNQVDW3MvYmCepbeC2ApxZo5LC72gA4PzHsQZNQQvmCgrIh0YWDFLpnAfX77A0HHhN9xmgxelDcakfuhhjCSKOn4o2AsD23SsYB/0glbENySTOZxBH+TpfcVoUQPlX8HzVcAKMXhpjgev8QXhVbc9Gu8eO/G5knL6sJ6q+QMwQtJrENHhokCgpUvHSrzwOXaU8trim9ajCU2vxpxGqOUE3yAj9mfZh+wVs 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: List-Subscribe: List-Unsubscribe: On Thu, May 23 2024 at 23:03, Vlastimil Babka wrote: > On 5/23/24 12:36 PM, Thomas Gleixner wrote: >>> ------------[ cut here ]------------ >>> DEBUG_LOCKS_WARN_ON(l->owner) >>> WARNING: CPU: 3 PID: 5221 at include/linux/local_lock_internal.h:30 local_lock_acquire include/linux/local_lock_internal.h:30 [inline] >>> WARNING: CPU: 3 PID: 5221 at include/linux/local_lock_internal.h:30 flush_slab mm/slub.c:3088 [inline] >>> WARNING: CPU: 3 PID: 5221 at include/linux/local_lock_internal.h:30 flush_cpu_slab+0x37f/0x410 mm/slub.c:3146 > > I'm puzzled by this. We use local_lock_irqsave() on !PREEMPT_RT everywhere. > IIUC this warning says we did the irqsave() and then found out somebody else > already set the owner? But that means they also did that irqsave() and set > themselves as l->owner. Does that mey there would be a spurious irq enable > that didn't go through local_unlock_irqrestore()? > > Also this particular stack is from the work, which is scheduled by > queue_work_on() in flush_all_cpus_locked(), which also has a > lockdep_assert_cpus_held() so it should fullfill the "the caller must ensure > the cpu doesn't go away" property. But I think even if this ended up on the > wrong cpu (for the full duration or migrated while processing the work item) > somehow, it wouldn't be able to cause such warning, but rather corrupt > something else Indeed. There is another report which makes no sense either: https://lore.kernel.org/lkml/000000000000fa09d906191c3ee5@google.com Both look like data corropution issues caused by whatever... Thanks, tglx