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=1794064985; b=w8ursrl7A+5bED7zKtnj+ipb9oBaWXRb16C6tZ12CZqLSg77fS3Ov6hLvHtC60doq6ja ue0u6u7m9Gaf3Af/be2ZoiyQWbbJ4S+hbJcsKc8vIgRN/nx8KM1dhqijCL5mIbV/twRxr 8tH8786IMUnu1EzNzZewdu7sYM/er4OEr1EzqdtUANkShklnSRkBBdbBzwzppnb2Vgr7U 2ipU/cNhPJPF6KN/z4t51pEbj5tfeV+5V5izGKp82it7MnaCTRg3PVq6S1pjCtc00bUFv I316AtwuHe5mqcrxW16+Lw/RcV4fZVodUmK4X+Vbkj3FxU/EuQHVtXbalpkeUCYfnAw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064985; 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=J+wKQQOftvwthBPFbuTpM6TxVzWwFXV26hqrvnHGD7w=; b=FmXKBG3PXjlRU5XR4t50of8HYc5eSUylTgud9wLWAR786vgEPAUn22uG45iAjw7plWxL SWaNrD8F9EmRi1ksJ9Jk3JZDrWwvzs1StrLBqoR/pn0lbaTPoesYMWNgtZ7yRvlRxwCNX tiQnMs8qRHJ1VpukrRlOy7eQDbGsw9BDADKZ/39pOd55FYIiqWVQj+UMo0LU8Y6796KJS vLvOWX/YGaVedO5vmvsC6xQSbtexcebdGkAS6i30GgWSiuHlI3rcvw+GoI3hDGYzr12Bb 8+kPHJtt4F5ExsmIoEK0VbMyPVNYU8HpoLkmjLloTeisifIB1TEJiGs7QDouI6NI/qg== 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=H4NlFxQ+; 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 6D6B5606A9FC; Sat, 7 Nov 2026 15:23:05 +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=H4NlFxQ+ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13DC41F0089F; Sat, 7 Nov 2026 15:23:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064985; bh=J+wKQQOftvwthBPFbuTpM6TxVzWwFXV26hqrvnHGD7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=H4NlFxQ+V21YJvVyZjR+7FIJouq3vWt4iJHMd3m+q2Tr6+AvW5up3lanG44mlHWBm nKy/mwVRg7qO2bEsk2KGpA8c5giZuBxBNWiqZxioalxjcGHAV3cpRk/2mKnHrRG84q 60mL6PobB+h/d8rgLnZl2AVJCujjQJQcdfu96XIg= 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 7.3 0860/1257] alpha: only use a targeted tbi() when the target mm is really current Date: Sat, 7 Nov 2026 08:52:36 -0500 Message-ID: <20261107135003.082007630@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Magnus Lindholm [ Upstream commit 0d92845ac5dbc79e4ac4810b33c673f4c1c227e3 ] ipi_flush_tlb_page() gates a targeted tbi() on current->active_mm. tbi() acts on the address space context currently loaded on the CPU, so it is only guaranteed to reach an mm's translations when a thread of that mm is running there. current->active_mm is not sufficient: under lazy TLB an idle or kernel task keeps an mm as its active_mm while a different ASN is loaded, so the invalidate is issued against the wrong context and the stale entry can survive. Nothing retires the old ASN afterwards either, mm->context[cpu] still being valid, so the resuming thread can reuse it. Test current->mm instead and otherwise fall back to flush_tlb_other(), which clears mm->context[cpu] and forces a fresh ASN at the next switch whatever is loaded now. For an mm borrowed through kthread_use_mm(), patch 1 of this series installs the context before the task can take a shootdown IPI. The current->mm test therefore covers that case as well. 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/20261010142533.974797-4-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 ed06367ece574..1ad448105201f 100644 --- a/arch/alpha/kernel/smp.c +++ b/arch/alpha/kernel/smp.c @@ -669,7 +669,8 @@ ipi_flush_tlb_page(void *x) struct flush_tlb_page_struct *data = x; struct mm_struct * mm = data->mm; - if (mm == current->active_mm && !asn_locked()) + /* A targeted tbi() needs a thread of MM to be current. */ + if (mm == current->mm && !asn_locked()) flush_tlb_current_page(mm, data->vma, data->addr); else flush_tlb_other(mm); -- 2.53.0