From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-170.mta1.migadu.com (out-170.mta1.migadu.com [95.215.58.170]) (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 92294306486 for ; Sat, 25 Jul 2026 13:27:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784986036; cv=none; b=p0fb6V+uDNTkqlNlRkLeIzxXTioLXAhtJOl5OdAM5qQw0Mog3MqPuSu/DGW7TBcq7ie8m+ad90TPTqeZH23uxxVoaqtps1+WiRuCm3zjiOqw+LpXL7ZpJ1fDgG1ZmT8AnSn4v9PzPQyTXcrXKqYEqcbNCRZzV8r/gQ6wknFIDzo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784986036; c=relaxed/simple; bh=dXnO2CVcVShG8lP+gpd8VYYjwBsfavrtuqXmi6o1zdM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=shkTttDxTwv1iNlTbYri2b+zrQPhvFMLDstwZtiBOcuRcIAz/nLd4H4IfssQmX/S9K/50leg6+Q/EhuHw6OseMc6JtdsuPX7xe7m0bHh2roxv0F//LsFtKgl8KitPeKeQrerF0p41YhtE1SLo66fbOGH2SU9U1t2Gr6yewOy9xU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=LvT3B+tC; arc=none smtp.client-ip=95.215.58.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="LvT3B+tC" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784986022; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=GlVzZJS0JTsV98D/V1kP7SM0ZnBbLTv2sUFIA2Id9Mk=; b=LvT3B+tCQVTCVDHWaj4oWobopdhM4Dsq2DWL05AOewKFErmevCAuZaV9+YVcutUex85isB hieRII+6QQEbRGQjfbNPKBQQ5pV7hBDRNI9ldnA0E1tJB09n7DgoQiMy+lSndZm8pchore eDV3x1YvvkFrh+rzf3qkwA8+jcKP8B0= From: Leon Hwang To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , Shuah Khan , Sechang Lim , Varun R Mallya , Leon Hwang , Viktor Malik , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH bpf-next v2 0/2] bpf: Fix sleepable check for tracing prog Date: Sat, 25 Jul 2026 21:26:22 +0800 Message-ID: <20260725132624.78373-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT When CONFIG_FUNCTION_ERROR_INJECTION is disabled, a sleepable tracing prog is allowed to attach to '__x64_'-alike prefix symbols. It is because the verifier does not verify whether the symbol is a kernel function or a bpf prog. That said, a sleepable tracing prog is allowed to attach to a bpf prog target whose name has '__x64_'-alike prefix. For example, a sleepable fentry prog attaches to a '__x64_sys_nop' XDP prog, and copies buffer from a user pointer with bpf_copy_from_user() helper. After attaching the XDP prog to lo interface, the kernel BUG could be triggered by 'ping -c 1 -W 1 127.0.0.1': [ 3.460756] BUG: sleeping function called from invalid context at kernel/bpf/trampoline.c:1324 Fix it by disallowing sleepable tracing prog always when its target is bpf prog. Changes: v1 -> v2: * Drop redundant 'prog->sleepable' check. * Collect Acked-by from Viktor, Thanks. * v1: https://lore.kernel.org/bpf/20260724141422.10463-1-leon.hwang@linux.dev/ Leon Hwang (2): bpf: Fix sleepable check for tracing prog selftests/bpf: Verify rejection of sleepable tracing prog kernel/bpf/verifier.c | 9 ++- .../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 57 +++++++++++++++++++ .../selftests/bpf/progs/fentry_sleepable.c | 19 +++++++ tools/testing/selftests/bpf/progs/xdp_dummy.c | 6 ++ 4 files changed, 88 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/fentry_sleepable.c -- 2.55.0