From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4996F145FE0 for ; Mon, 29 Jul 2024 11:30:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722252602; cv=none; b=pjpZgAqTNdguoHonCqSyq1XXiySpyaA8SnNT1dvPlDk3+TdbJd/Sy7FBMLrYmXsUEby1balbYewY8S7ZniSG5clVO7Wyxhv71h7K328Tmgu2LseNFr+oWW5dk4k6PtuyeGq6UhwnvQzRISZR4BZw4yQtYmwPL1Qxw8ObVrU6Cyk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722252602; c=relaxed/simple; bh=TipJLAp0H5sPs0dIPuvouVg0CMwOZ5mJT4nmIW/gW74=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WKSGpkHKyPYoyNy4RLVykXmR+FLDNGI1jMrZFDKMLokwywM+BJfVSOygkrTHbSMoLXX6Vd2saldD0Kb/YJGW+Av2fgUxp0ceLBqWPx5wNRNxfzoth4gyXO0KOxov5IWkZGJAGl6Z0AnF725TCv/Ne7leGB9/hMOvcGxWj7HYQgc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=VPFnkrdy; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="VPFnkrdy" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 2082840E01BB; Mon, 29 Jul 2024 11:29:59 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id GHOm4pgWY5FW; Mon, 29 Jul 2024 11:29:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1722252595; bh=KG8CQ1KpLh65pKJVY3yFSoZNet0pxmhw1NBNwH+ki5o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VPFnkrdy9eI+mk47prim7u5B0t0009V/erEUG3ooBQFZvphCNy6oo1hhJjCcX6Qpc +cUFDvI34Pr7lVGVRjbXi0KXT09YETU4DyX3KYJ/HF7TsKJuQWEF172FxrD+/aSnvO pekJi6ylLN4isF5860ktgonn//4dB2LDy2yMdiZCUq7sNHlXmamMp3Ot1IIhm5If36 AiNWhDNgjCb7NJW667wBRmUJUDj7R+qfMN7qRkBCQ/x1Lx76S4PZ1H3mL2LV7nsHp+ NFvSVNv31tkNqjijhIUqCfA7BjFn4ZbgNy0xDFMp0rgvVl+iOUPnNfhpjYOL6BuJ3G 9cPQ/zlL+MBustMik0w/Rf1eqOUvKWC6izx+3pjeD+KpSVn0G1E6b0Hei1/3jhG9Nr DAmd/ZeygtcSnqb2sHHY+5B5++jtq4TKwsSxsuPGfs6AXzWI143pbaVm/8Cw61P1OB NBWgPByMVnhvkoKMibfEj7zqZYhvFE17W4jpKU//BGAYgU8eSb24wjU4jzq2QU2cH6 Z2K2Trdxx/ciZWAbzR68+93iRqEcGfUybYglzVGcH5mHbmge/ThOp0+wjPtPMrHRt0 xaXscIpeEreuimI9Kip4fnf9KRMQssPkz3hPQoro1LfEIbtoHX77CIlx5nshl++zp4 YGFwEcqoPWUKTJ/Fzv1di8EI= Received: from zn.tnic (p5de8ee85.dip0.t-ipconnect.de [93.232.238.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id E173340E00F4; Mon, 29 Jul 2024 11:29:38 +0000 (UTC) Date: Mon, 29 Jul 2024 13:29:38 +0200 From: Borislav Petkov To: Jonathan Cameron Cc: Mikhail Gavrilov , rafael.j.wysocki@intel.com, catalin.marinas@arm.com, Ingo Molnar , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Terry.bowman@amd.com, linuxarm@huawei.com, guohanjun@huawei.com, gshan@redhat.com, miguel.luis@oracle.com, Linux List Kernel Mailing , Linux regressions mailing list , shameerali.kolothum.thodi@huawei.com Subject: Re: [PATCH] x86/aperfmperf: Fix deadlock on cpu_hotplug_lock Message-ID: <20240729112938.GCZqd9IvTZmKXVGt9T@fat_crate.local> References: <20240729105504.2170-1-Jonathan.Cameron@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240729105504.2170-1-Jonathan.Cameron@huawei.com> On Mon, Jul 29, 2024 at 11:55:04AM +0100, Jonathan Cameron wrote: > The broken patch results in a call to init_freq_invariance_cppc() in a CPU > hotplug handler in both the path for initially present CPUs and those > hotplugged later. That function includes a one time call to > amd_set_max_freq_ratio() which in turn calls freq_invariance_enable() that > has a static_branch_enable() which takes the cpu_hotlug_lock which is > already held. > > Avoid the deadlock by using static_branch_enable_cpuslocked() as the lock > will always be already held. The equivalent path on Intel does not > already hold this lock, so take it around the call to > freq_invariance_enable(), which results in it being held over the call to > register_syscall_ops, which looks to be safe to do. > > Fixes: c1385c1f0ba3 ("ACPI: processor: Simplify initial onlining to use same path for cold and hotplug") > Reported-by: Mikhail Gavrilov > Closes: https://lore.kernel.org/all/CABXGCsPvqBfL5hQDOARwfqasLRJ_eNPBbCngZ257HOe=xbWDkA@mail.gmail.com/ > Suggested-by: Thomas Gleixner > Tested-by: Mikhail Gavrilov > Signed-off-by: Jonathan Cameron > --- > arch/x86/kernel/cpu/aperfmperf.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) Tested-by: Borislav Petkov (AMD) I'll take it through tip if no one objects... Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette