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 1ED3344CAE9 for ; Thu, 26 Feb 2026 16:15:47 +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=1772122548; cv=none; b=a8xM0x25UuoJQ9JvtJq7KxAvpiHr8iRoDvOrK3aFGi3Tf4bCG1/7Z7Fccyz1qobPXQxEgbUjEc0tjs9yfQS4Uyuhoeb/J7aeP1fHFrYuIN/TtqjTlQ/o/Ej8fU8kVkg15w0S4c8euvOOCZAC5DSlAE3WHftI3Gjb0XokR859HaA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772122548; c=relaxed/simple; bh=opgV5IOMQS++JhFgCfNlfE0WpYn6znZgtya0Dk/E3fU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gh2ZLT+Ft/JHJCExEEAgdaKqLkUg68hUgwxY1lmDwLLRTK+zXnXx+kT1Mk23RTn0ueRSqhH0lavEf5W1uv7IjN76N2JPwIuRnJRhXhPV6Np93JYc7iV61+Zpr1zgB4iRDgYllFtRObr9o9srC2BcK1zVaXXgN7HW+4JWWYuZTAM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Zt+y22BQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Zt+y22BQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FE12C116C6; Thu, 26 Feb 2026 16:15:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772122547; bh=opgV5IOMQS++JhFgCfNlfE0WpYn6znZgtya0Dk/E3fU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zt+y22BQoCKfzbbT7xCDpsjz2RHmQGf8oExn1+pBy1imyKKO11OAa6CTdoOZGddDP 2WyqRVX4zUz3OMXxPosXmvbNXFS8Cq2C3LG1aTubyvOex8BqywLAWwwucFdXILeKfI leWD/8v7CwKUanereUn1tgV3LT1RYAG/c4rX9E7Tvvl3tChfMcUDjTg5fbF+rijrIb x6LppvIbz0zTzF+WkTdpdX/0OYNNECJ+0pzJMrC0g5egSgU5LMomqeLl5TGBr/jqrn xyihTcJUMc/nmt+Vx3wb1NjOcguzgDdndxfjO+zRH46iajikaFDo6VH+EOrbBcGIAu SHVD8zi0DYHZA== From: Puranjay Mohan To: bpf@vger.kernel.org Cc: Puranjay Mohan , Puranjay Mohan , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Mykyta Yatsenko , kernel-team@meta.com Subject: [PATCH bpf v5 7/8] bpf: Add split iteration support to task_vma iterator Date: Thu, 26 Feb 2026 08:14:56 -0800 Message-ID: <20260226161500.775715-8-puranjay@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260226161500.775715-1-puranjay@kernel.org> References: <20260226161500.775715-1-puranjay@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Wire up the task_vma iterator to use the KF_ACQUIRE/KF_RELEASE and KF_FORBID_FAULT infrastructure from the previous commits. Annotate bpf_iter_task_vma_next with KF_ACQUIRE | KF_FORBID_FAULT so each returned VMA pointer becomes a tracked reference that prevents faulting. Add bpf_iter_task_vma_release(it__iter) with KF_RELEASE that releases the mmap read lock, drops the acquired reference, and re-enables sleeping. The next call to _next will re-acquire the lock via mmap_read_trylock(). This enables a split iteration pattern: bpf_for_each(task_vma, vma, task, 0) { u64 start = vma->vm_start; /* vma access allowed, sleeping forbidden */ bpf_iter_task_vma_release(&___it); /* vma access forbidden, sleeping allowed */ bpf_copy_from_user(&buf, sizeof(buf), (void *)start); } Signed-off-by: Puranjay Mohan --- kernel/bpf/helpers.c | 3 ++- kernel/bpf/task_iter.c | 10 ++++++++++ 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 6eb6c82ed2ee..e4d0a3a62428 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -4605,8 +4605,9 @@ BTF_ID_FLAGS(func, bpf_iter_num_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_num_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_iter_task_vma_new, KF_ITER_NEW | KF_RCU) -BTF_ID_FLAGS(func, bpf_iter_task_vma_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_task_vma_next, KF_ITER_NEXT | KF_RET_NULL | KF_ACQUIRE | KF_FORBID_FAULT) BTF_ID_FLAGS(func, bpf_iter_task_vma_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_iter_task_vma_release, KF_RELEASE) #ifdef CONFIG_CGROUPS BTF_ID_FLAGS(func, bpf_iter_css_task_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_css_task_next, KF_ITER_NEXT | KF_RET_NULL) diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c index a85115c191e4..55b264d634db 100644 --- a/kernel/bpf/task_iter.c +++ b/kernel/bpf/task_iter.c @@ -879,6 +879,16 @@ __bpf_kfunc struct vm_area_struct *bpf_iter_task_vma_next(struct bpf_iter_task_v return vma; } +__bpf_kfunc void bpf_iter_task_vma_release(struct bpf_iter_task_vma *it__iter) +{ + struct bpf_iter_task_vma_kern *kit = (void *)it__iter; + + if (kit->data && kit->data->locked) { + bpf_mmap_unlock_mm(kit->data->work, kit->data->mm); + kit->data->locked = false; + } +} + __bpf_kfunc void bpf_iter_task_vma_destroy(struct bpf_iter_task_vma *it) { struct bpf_iter_task_vma_kern *kit = (void *)it; -- 2.47.3