From nobody Thu Apr 2 23:54:08 2026 Received: from mail-pj1-f43.google.com (mail-pj1-f43.google.com [209.85.216.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9B4CC284884 for ; Sat, 14 Feb 2026 04:36:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.43 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771043810; cv=none; b=ovLM6F5AU74Sf1+d7oB4AgPjlJjs1cxButLGymRgRDQiMBRBC8oMGLmH4k4Hkgw//TlcIw4GO5JkX3NLJLh9rSr+Ol7DcR+YmZ1OcjhnvGvOpORbtL8acVLZ8C8tdrnEWHkgSrJ7kYLA5bEnQvGRPNwGbAhDToM0FlNTEM4LBog= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771043810; c=relaxed/simple; bh=0Ut/Yd2xFzBBknyWQqwazN3LxjtJIbDOmzRkADmWq9U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GeHrxfMBihdyETswZWmJuvbBWEYSmFjrKLdgqYYVpMylnab1tpRdDTeFFVPOLsKQDDbWRzL+r6flqQLh2/KdjxFR5YDLzrMrLBH3OrulTlwbEau9OIJJnrzhX+G3Y6nSRyu2E7YGl07JtzrNiR3r9bZArWMao5vhwbz8D62ier0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=W+/QCuMA; arc=none smtp.client-ip=209.85.216.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="W+/QCuMA" Received: by mail-pj1-f43.google.com with SMTP id 98e67ed59e1d1-354a7b089bbso929800a91.2 for ; Fri, 13 Feb 2026 20:36:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1771043809; x=1771648609; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=nxayVJFfRrkf5xz/bcJOQ8q9k4PoLRBwxedlXN2B8nI=; b=W+/QCuMAgFk9YazxBDhqo4VqvXT7mS1tP++xH3gilwDIV7dRJVc6X9ZJsU4jlhwGBK qv9uZxBUexlGvYAFktWM+tbbSO7ORK7syIMw1BDLfGo2yM6fbBvnEkstbOHe2RF+r4uj 9Avzfy6yHNX2QjtttmYsSJTzAynYFy6wfMjE/3v9IKm+djstcX51QIzv11s8k1MyG18T hAstp/0KfL0KTa2vfFazDk9r9XOcT/1dGXr88DdNHWMALuy7PGXO/7/Ay8BLXWT9ESvL w6hZ6D2rvmFihCVOGUBxZ+mJIH2YIrq2rAL1963x0u30AtOXXLu43JbjNgLViJdIXnqf 34Qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771043809; x=1771648609; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=nxayVJFfRrkf5xz/bcJOQ8q9k4PoLRBwxedlXN2B8nI=; b=jVnMQrq5TzRmKzfXV2yqXYwRIRqXHadhxB4l5yk0K4KzlRVAV3G/3wTIgCm/8c0PVA 8Pg+IbE64tAF1l17K9iCm+ZZXlXvVQ1kfuqHSfcqJdGRMiqyj4of4UHvej7aPkjxHqR9 eRUjyGAJXjR4zARZ0hirFJLWSE8Lx/Ni9Ty35Bk2Mq+/NrbHtEdC+//TNGgt97lt+CP0 +QEu8ElARBAMF1NNoD/wAPIRdudxsbg4/cSzbro42hl7YQjkm+nw5YpqXCnUaJzkq4mw goSo6na5Lq5MGzxQl/JCAUxsNPEAYXW7iSI+P9rNyFIGhZ8ph9SWu7aJaIbSgq/aBPan Dy6A== X-Gm-Message-State: AOJu0YzzmElHW2vGX8bSLJFDFZtXx0zR28ivWz42dhapiCGq5SWhVSkX MlNSUuf169GMHll42x3rvasHQSeJJ4OttPFEd19HSZFHSjzkiPALgUsP X-Gm-Gg: AZuq6aLCy5exZdEPbYKNpyx5uooEncXnM7Eukaoa7Ep7Z7grNM5vS1K2IkI0LTH+ztL QBfdK1vD5FpODglbKVOBaboAn29kIXuNNA/SoET/SXVqaEaFMh8NiEjxXmQp2C5E3uL7Rkus8Eq qJg8mHoeovdIbEDmVGIE3kvRxqH9CrVcA+KIiTT2OVQePaVDXpfBUJBpgNIc+oipe0iIOZiHVQ9 SXrznV+Ggqyq0+sG/VodtaSvGWM86ot/hO2X1pHtgPvOyw8Muzb+kHwWTLFIQ237rjXSmrmZx0/ LT7eDCx5hIhMiN7VenqiqUSMrfodNfy9GCNRabqCKdt2ECi9pL60i4nFXIeoqXnQxq3rVaJlx+z uWy4tPqMbf9hLAdUug9k00BFl64qDyP+BWHjTo1z4yOHLO+iN1g74wchuSAvkzCdZTspYcQlvlz jcVBHEps5m5iXNQK/8XXRVAk/WP/DtbzsbdS2IEQsIOcB61CnqT3fL X-Received: by 2002:a17:90b:134d:b0:356:2b1c:f629 with SMTP id 98e67ed59e1d1-356aad3caf5mr3372625a91.22.1771043808772; Fri, 13 Feb 2026 20:36:48 -0800 (PST) Received: from localhost.localdomain ([113.218.252.61]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-35662e53936sm13519815a91.1.2026.02.13.20.36.41 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 13 Feb 2026 20:36:48 -0800 (PST) From: Chengkaitao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, yangfeng@kylinos.cn, alexei.starovoitov@gmail.com Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Kaitao Cheng Subject: [PATCH v7 1/5] bpf: allow calling bpf_kptr_xchg while holding a lock Date: Sat, 14 Feb 2026 12:36:26 +0800 Message-ID: <20260214043630.38644-2-pilgrimtao@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260214043630.38644-1-pilgrimtao@gmail.com> References: <20260214043630.38644-1-pilgrimtao@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Kaitao Cheng For the following scenario: struct tree_node { struct bpf_rb_node node; struct request __kptr *req; u64 key; }; struct bpf_rb_root tree_root __contains(tree_node, node); struct bpf_spin_lock tree_lock; If we need to traverse all nodes in the rbtree, retrieve the __kptr pointer from each node, and read kernel data from the referenced object, using bpf_kptr_xchg appears unavoidable. This patch skips the BPF verifier checks for bpf_kptr_xchg when called while holding a lock. Signed-off-by: Kaitao Cheng --- kernel/bpf/verifier.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index edf5342b982f..2927a4622ff8 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -21044,7 +21044,8 @@ static int do_check_insn(struct bpf_verifier_env *e= nv, bool *do_print_state) =20 if (env->cur_state->active_locks) { if ((insn->src_reg =3D=3D BPF_REG_0 && - insn->imm !=3D BPF_FUNC_spin_unlock) || + insn->imm !=3D BPF_FUNC_spin_unlock && + insn->imm !=3D BPF_FUNC_kptr_xchg) || (insn->src_reg =3D=3D BPF_PSEUDO_KFUNC_CALL && (insn->off !=3D 0 || !kfunc_spin_allowed(insn->imm)))) { verbose(env, --=20 2.50.1 (Apple Git-155)