From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 15F131A00CF; Thu, 15 Aug 2024 14:04:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723730655; cv=none; b=BmRNot2DnDuJoGvI+BVL4C9x8erSuu/I7zfU5MFp37WqC+rbrPd7r6202+6+5xEGvXi2Vr+WhPNQoajzOOfgmb2dHy/u5gYASmEviC/vGfF/AXqr55ZJ3CRlVS6k9lF8gnmMLdTtEOpZ6lPERaoTxg9x9SBEqvwimclWU8+gSI0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723730655; c=relaxed/simple; bh=I3r3kucNWisc3NV7gTE4UdQAXbXDnla7pQ6HlK98H1o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NZ1kR0bE19UnqrWk+z03jO+bNzSqcJFh8qj6EKMfbdT/8tQVrWyX6LKxUZoN2FLGfbzv/GcFUA51nhnFLXa2VzoY518wVQBuCUtEB0IRz71rzDXkl7U1MNXM2UEDHbvcHnVNdnkr7qgBRtBov9S7HsoM6O8tQzVjPnjeJKLDFz8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Wnx6b0k2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Wnx6b0k2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E8CEC32786; Thu, 15 Aug 2024 14:04:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723730654; bh=I3r3kucNWisc3NV7gTE4UdQAXbXDnla7pQ6HlK98H1o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Wnx6b0k2+ousMoTs30LnBAI71GJoOQjqgUSmYeirwvB4QCM9TclYdEyJdKH1JXYZw Pvf8WZMax8zabTbn24V0wUv80GUOGXv664gnT9tvX92/PSPrJP9izBmYvbQkkOpS6w 0IjgvARY/LhZERFSaO78ckfjuRR3ZXMjcZPI5vTw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christophe Leroy , Shirisha Ganta , Mahesh Salgaonkar , Michael Ellerman , Jinjie Ruan Subject: [PATCH 5.15 476/484] powerpc: Avoid nmi_enter/nmi_exit in real mode interrupt. Date: Thu, 15 Aug 2024 15:25:34 +0200 Message-ID: <20240815131959.866659132@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240815131941.255804951@linuxfoundation.org> References: <20240815131941.255804951@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mahesh Salgaonkar commit 0db880fc865ffb522141ced4bfa66c12ab1fbb70 upstream. nmi_enter()/nmi_exit() touches per cpu variables which can lead to kernel crash when invoked during real mode interrupt handling (e.g. early HMI/MCE interrupt handler) if percpu allocation comes from vmalloc area. Early HMI/MCE handlers are called through DEFINE_INTERRUPT_HANDLER_NMI() wrapper which invokes nmi_enter/nmi_exit calls. We don't see any issue when percpu allocation is from the embedded first chunk. However with CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK enabled there are chances where percpu allocation can come from the vmalloc area. With kernel command line "percpu_alloc=page" we can force percpu allocation to come from vmalloc area and can see kernel crash in machine_check_early: [ 1.215714] NIP [c000000000e49eb4] rcu_nmi_enter+0x24/0x110 [ 1.215717] LR [c0000000000461a0] machine_check_early+0xf0/0x2c0 [ 1.215719] --- interrupt: 200 [ 1.215720] [c000000fffd73180] [0000000000000000] 0x0 (unreliable) [ 1.215722] [c000000fffd731b0] [0000000000000000] 0x0 [ 1.215724] [c000000fffd73210] [c000000000008364] machine_check_early_common+0x134/0x1f8 Fix this by avoiding use of nmi_enter()/nmi_exit() in real mode if percpu first chunk is not embedded. Reviewed-by: Christophe Leroy Tested-by: Shirisha Ganta Signed-off-by: Mahesh Salgaonkar Signed-off-by: Michael Ellerman Link: https://msgid.link/20240410043006.81577-1-mahesh@linux.ibm.com [ Conflicts in arch/powerpc/include/asm/interrupt.h because interrupt_nmi_enter_prepare() and interrupt_nmi_exit_prepare() has been refactored. ] Signed-off-by: Jinjie Ruan Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/include/asm/interrupt.h | 14 ++++++++++---- arch/powerpc/include/asm/percpu.h | 10 ++++++++++ arch/powerpc/kernel/setup_64.c | 2 ++ 3 files changed, 22 insertions(+), 4 deletions(-) --- a/arch/powerpc/include/asm/interrupt.h +++ b/arch/powerpc/include/asm/interrupt.h @@ -285,18 +285,24 @@ static inline void interrupt_nmi_enter_p /* * Do not use nmi_enter() for pseries hash guest taking a real-mode * NMI because not everything it touches is within the RMA limit. + * + * Likewise, do not use it in real mode if percpu first chunk is not + * embedded. With CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK enabled there + * are chances where percpu allocation can come from vmalloc area. */ - if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64) || + if ((!IS_ENABLED(CONFIG_PPC_BOOK3S_64) || !firmware_has_feature(FW_FEATURE_LPAR) || - radix_enabled() || (mfmsr() & MSR_DR)) + radix_enabled() || (mfmsr() & MSR_DR)) && + !percpu_first_chunk_is_paged) nmi_enter(); } static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state) { - if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64) || + if ((!IS_ENABLED(CONFIG_PPC_BOOK3S_64) || !firmware_has_feature(FW_FEATURE_LPAR) || - radix_enabled() || (mfmsr() & MSR_DR)) + radix_enabled() || (mfmsr() & MSR_DR)) && + !percpu_first_chunk_is_paged) nmi_exit(); /* --- a/arch/powerpc/include/asm/percpu.h +++ b/arch/powerpc/include/asm/percpu.h @@ -15,6 +15,16 @@ #endif /* CONFIG_SMP */ #endif /* __powerpc64__ */ +#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK) && defined(CONFIG_SMP) +#include +DECLARE_STATIC_KEY_FALSE(__percpu_first_chunk_is_paged); + +#define percpu_first_chunk_is_paged \ + (static_key_enabled(&__percpu_first_chunk_is_paged.key)) +#else +#define percpu_first_chunk_is_paged false +#endif /* CONFIG_PPC64 && CONFIG_SMP */ + #include #include --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -825,6 +825,7 @@ static int pcpu_cpu_distance(unsigned in unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; EXPORT_SYMBOL(__per_cpu_offset); +DEFINE_STATIC_KEY_FALSE(__percpu_first_chunk_is_paged); static void __init pcpu_populate_pte(unsigned long addr) { @@ -904,6 +905,7 @@ void __init setup_per_cpu_areas(void) if (rc < 0) panic("cannot initialize percpu area (err=%d)", rc); + static_key_enable(&__percpu_first_chunk_is_paged.key); delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; for_each_possible_cpu(cpu) { __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];