From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794063482; b=z3EAHcFQ3He2XVtvavvjoLKNms47P8DSUILtN+FZa9g/7B9v9WPw4qbmA1Nr+lbACLdP ftUNS1npXigqfbY5+ZwVzsAmPefG+wDrm/ato7hsti+pMSYZSPXZr4P07ZLRmKVo0BC73 KclG1QP9TjCkuNqom3wcmrKSSDb1rwUfxaRZ2WA9dV3eHPs/qVYzBCQdHQX5R+97UBxY7 wFqIR4Y4RhXIjTKT4u9nmJ/B6F1myLYv+CaCbbgAcGVbo/vIRQCsMTXHnJn9edZQtelqr QtmRfqTw1PMb+EoUxiCd+mmyvhxTtFUjX8lP/IztFkJE0IhKhzD3RTttq9+seO0Esjg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063482; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=PNTtMMQYUgZJOrR3WcvU2YKfht0cQN3vKF+3x/Ys3Ds=; b=BJzKLx36SyDl5AJbmpBixDCFNtda5ZwCfisaA/kzw+PY1Gy9oOXlfCsqi3iDW4NZYoxx DBMJ3CP3G7FhmcEeTsfVp1U5QFuRGEnz/t6c0HG7fCuTkSff7Rb6s6oxzzPs6LmIuwY9s ci25TQBb9xr4vFdjgU/NqPWMymCbNl4FQMLeVpBekubAPJxxvw6kPlDDR3kFGx7hPnFlR 5eQHsZgWOJ4OZ1WU19CqrpnYXCX8sxXdQ7Nmb0nz5afbvkUEyycUhAa82L46aIRrLTQl6 psuWJT2aUchr0UoysoDVD7ncDEqj1HZpKzUCOBzf5QtYZM0+Ot2ihcEjevNh8lFLpog== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="a07/g0pF"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 442DA606A9DA; Sat, 7 Nov 2026 14:58:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=a07/g0pF Received: by smtp.kernel.org (Postfix) with ESMTPSA id C50371F008A5; Sat, 7 Nov 2026 14:58:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063481; bh=PNTtMMQYUgZJOrR3WcvU2YKfht0cQN3vKF+3x/Ys3Ds=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=a07/g0pFQwhxMKEz8CMwtewAYO4ANnSBTr0AO2Y0rHVujzhcql8BkMZoG+wkRTuAU YNacsicO2+leY8qrlKFLvb+2MWJzWQb11VbfqEA3A1ms+IScDmTmI9OP7Pc/K9Qh2f N1AqZJnNSg/H1F6aOQ9kNWcDstYNeJnnMAqmwM1g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Matt Turner , Magnus Lindholm , Sasha Levin Subject: [PATCH 6.18 629/869] alpha: fix the local TLB invalidate in flush_tlb_page() Date: Sat, 7 Nov 2026 08:55:11 -0500 Message-ID: <20261107134914.314353170@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Magnus Lindholm [ Upstream commit 32f4dd420d626f96128fcfeea2ab24760b4f21a6 ] flush_tlb_page() invalidates the calling CPU itself before asking the others, and gates that on current->active_mm. For a non-executable vma that means a targeted tbi(2, addr), which acts on the context currently loaded and is only guaranteed to invalidate the intended translations when the target mm's context is the loaded one. A lazy active_mm does not establish that, so as in ipi_flush_tlb_page() the target mm's stale translations can survive, and nothing forces the old ASN to be retired afterwards. Test current->mm instead. A lazy caller then takes the flush_tlb_other() branch added by the previous patch, retiring its local context. Adding that branch first preserves the local invalidate at every step, including on EV7 where a targeted tbi() against a foreign ASN appeared to work. Which callers reach here with a foreign mm depends on the configuration. folio_mkclean(), from the writeback flusher kworker that has no mm of its own, accounted for about half the calls during writeback of a shared mapping and none at all on anonymous memory. Those counts were measured with CONFIG_COMPACTION=n: with COMPACTION=y, asm/pgtable.h overrides ptep_clear_flush() to call migrate_flush_tlb_page(), which rendezvouses with every CPU and handles the context itself, so folio_mkclean() does not reach this function. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reviewed-by: Matt Turner Signed-off-by: Magnus Lindholm Link: https://lore.kernel.org/r/20261010142533.974797-6-linmag7@gmail.com Signed-off-by: Magnus Lindholm Signed-off-by: Sasha Levin --- arch/alpha/kernel/smp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c index e4ba0aab8a669..a5a42ae4a7d80 100644 --- a/arch/alpha/kernel/smp.c +++ b/arch/alpha/kernel/smp.c @@ -684,7 +684,8 @@ flush_tlb_page(struct vm_area_struct *vma, unsigned long addr) preempt_disable(); - if (mm == current->active_mm) { + /* As in ipi_flush_tlb_page(): a targeted tbi() needs MM current. */ + if (mm == current->mm) { flush_tlb_current_page(mm, vma, addr); if (atomic_read(&mm->mm_users) <= 1) { int cpu, this_cpu = smp_processor_id(); -- 2.53.0