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 92ADD3587BC for ; Wed, 21 Jan 2026 03:26:45 +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=1768966005; cv=none; b=NcB6KA5N0mdbHAwa5GL7yPP7qpJ3vGooLu+jiK/tv+KH/1ep6dSIJ/0al3PMQqQBhMTaDwm/cznlTOVOAt+/DVQWtEQWsLHKFd2+qknXQUe88485gXyjyFjXDLMcMp0/bIOHkS2ZyJjze4aXF0L7Rxa58M7B8IH3+HRC3IuRwNE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768966005; c=relaxed/simple; bh=XurQPQgKFM9Agz+HZGyx+Zcjmg3llmj6wTnLbgQo5IQ=; h=Date:To:From:Subject:Message-Id; b=mzTdB5n2lBdNwOVjCJzv7WB03ozF6/FP8sMmp0q68Q3OA29EaPLFlXHR2yGwWTw3PBXcsIfPT6XNRLsmDMbMzK4s/yG/cW/FY8oTmup8zzrWSnCkK3RmvoPmlf302xwdMoOi4IvMw9zuyuI9rkEvKvnxAdCur2gLzksEH/jfGXU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=oht46eJe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="oht46eJe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DFF9C16AAE; Wed, 21 Jan 2026 03:26:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1768966005; bh=XurQPQgKFM9Agz+HZGyx+Zcjmg3llmj6wTnLbgQo5IQ=; h=Date:To:From:Subject:From; b=oht46eJeG5eeK/3670IXujBfJQLx2Vj52DT3BH0aF7al3P0r/3HqQj3S1wtR1ILDF g852t2lYYHyOCBNYK8MoWm9GIeQYUEXHDK++3InTwZkoNnrK9Yp3GCjz8M9vULC3nC dqiTpnuwictuDT8N4a8jEXeliiDAPRnpAsYh6ub8= Date: Tue, 20 Jan 2026 19:26:44 -0800 To: mm-commits@vger.kernel.org,yeoreum.yun@arm.com,will@kernel.org,venkat88@linux.ibm.com,vbabka@suse.cz,tglx@linutronix.de,surenb@google.com,ryan.roberts@arm.com,rppt@kernel.org,ritesh.list@gmail.com,peterz@infradead.org,npiggin@gmail.com,mpe@ellerman.id.au,mingo@redhat.com,mhocko@suse.com,maddy@linux.ibm.com,lorenzo.stoakes@oracle.com,liam.howlett@oracle.com,jgross@suse.com,jannh@google.com,hpa@zytor.com,dwmw2@infradead.org,david@redhat.com,david@kernel.org,davem@davemloft.net,christophe.leroy@csgroup.eu,catalin.marinas@arm.com,bp@alien8.de,boris.ostrovsky@oracle.com,anshuman.khandual@arm.com,andreas@gaisler.com,agordeev@linux.ibm.com,kevin.brodsky@arm.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-bail-out-of-lazy_mmu_mode_-in-interrupt-context.patch removed from -mm tree Message-Id: <20260121032645.2DFF9C16AAE@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm: bail out of lazy_mmu_mode_* in interrupt context has been removed from the -mm tree. Its filename was mm-bail-out-of-lazy_mmu_mode_-in-interrupt-context.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Kevin Brodsky Subject: mm: bail out of lazy_mmu_mode_* in interrupt context Date: Mon, 15 Dec 2025 15:03:17 +0000 The lazy MMU mode cannot be used in interrupt context. This is documented in , but isn't consistently handled across architectures. arm64 ensures that calls to lazy_mmu_mode_* have no effect in interrupt context, because such calls do occur in certain configurations - see commit b81c688426a9 ("arm64/mm: Disable barrier batching in interrupt contexts"). Other architectures do not check this situation, most likely because it hasn't occurred so far. Let's handle this in the new generic lazy_mmu layer, in the same fashion as arm64: bail out of lazy_mmu_mode_* if in_interrupt(). Also remove the arm64 handling that is now redundant. Both arm64 and x86/Xen also ensure that any lazy MMU optimisation is disabled while in interrupt (see queue_pte_barriers() and xen_get_lazy_mode() respectively). This will be handled in the generic layer in a subsequent patch. Link: https://lkml.kernel.org/r/20251215150323.2218608-9-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky Acked-by: David Hildenbrand (Red Hat) Reviewed-by: Anshuman Khandual Reviewed-by: Yeoreum Yun Cc: Alexander Gordeev Cc: Andreas Larsson Cc: Borislav Betkov Cc: Boris Ostrovsky Cc: Catalin Marinas Cc: Christophe Leroy Cc: David Hildenbrand Cc: David S. Miller Cc: David Woodhouse Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jann Horn Cc: Juegren Gross Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Ritesh Harjani (IBM) Cc: Ryan Roberts Cc: Suren Baghdasaryan Cc: Thomas Gleinxer Cc: Venkat Rao Bagalkote Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm64/include/asm/pgtable.h | 9 --------- include/linux/pgtable.h | 17 ++++++++++++++++- 2 files changed, 16 insertions(+), 10 deletions(-) --- a/arch/arm64/include/asm/pgtable.h~mm-bail-out-of-lazy_mmu_mode_-in-interrupt-context +++ a/arch/arm64/include/asm/pgtable.h @@ -94,26 +94,17 @@ static inline void arch_enter_lazy_mmu_m * keeps tracking simple. */ - if (in_interrupt()) - return; - set_thread_flag(TIF_LAZY_MMU); } static inline void arch_flush_lazy_mmu_mode(void) { - if (in_interrupt()) - return; - if (test_and_clear_thread_flag(TIF_LAZY_MMU_PENDING)) emit_pte_barriers(); } static inline void arch_leave_lazy_mmu_mode(void) { - if (in_interrupt()) - return; - arch_flush_lazy_mmu_mode(); clear_thread_flag(TIF_LAZY_MMU); } --- a/include/linux/pgtable.h~mm-bail-out-of-lazy_mmu_mode_-in-interrupt-context +++ a/include/linux/pgtable.h @@ -233,26 +233,41 @@ static inline int pmd_dirty(pmd_t pmd) * preemption, as a consequence generic code may not sleep while the lazy MMU * mode is active. * - * Nesting is not permitted and the mode cannot be used in interrupt context. + * The mode is disabled in interrupt context and calls to the lazy_mmu API have + * no effect. + * + * Nesting is not permitted. */ #ifdef CONFIG_ARCH_HAS_LAZY_MMU_MODE static inline void lazy_mmu_mode_enable(void) { + if (in_interrupt()) + return; + arch_enter_lazy_mmu_mode(); } static inline void lazy_mmu_mode_disable(void) { + if (in_interrupt()) + return; + arch_leave_lazy_mmu_mode(); } static inline void lazy_mmu_mode_pause(void) { + if (in_interrupt()) + return; + arch_leave_lazy_mmu_mode(); } static inline void lazy_mmu_mode_resume(void) { + if (in_interrupt()) + return; + arch_enter_lazy_mmu_mode(); } #else _ Patches currently in -mm which might be from kevin.brodsky@arm.com are selftests-mm-default-kdir-to-build-directory.patch selftests-mm-remove-flaky-header-check.patch selftests-mm-pass-down-full-cc-and-cflags-to-check_configsh.patch selftests-mm-fix-usage-of-force_read-in-cow-tests.patch selftests-mm-introduce-helper-to-read-every-page-in-range.patch selftests-mm-fix-faulting-in-code-in-pagemap_ioctl-test.patch selftests-mm-fix-exit-code-in-pagemap_ioctl.patch selftests-mm-report-skip-in-pfnmap-if-a-check-fails.patch