From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) (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 BFFF743B3EA for ; Fri, 24 Jul 2026 14:14:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784902496; cv=none; b=Sd2v79gyImDL72WToWNJ9+WIxWhXlg2WfFZmXa89xawpLeviHpGBgKBYZbTeigaBVlEoMUyjB/LDdKSY4am0FPn0VJqhwskSu61wM0Ojxq5CuuDS8nvOVDE5tp9IQS94Z967CLN68DAPj7B2P/dZN9nPWLz2yRJRPoyzd69Hpe0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784902496; c=relaxed/simple; bh=Tt+UEmTFxd7iIyw7MfgL+uNlQo6gA6khaMWvBDZLW3Y=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=UkRIsj58O083L6rXA0KV2Fx2gL0rnTHXlXjaVXKPhTFz56KTR4CDELUA8EcjoTOOf09974StMOs+flgFryi5TMqHC6+uJOTPdNdAXGxNaWa1KvJ5Dl3eSUD/MDlT8aVupulEXBkcdBq0cYJtq1j5pFj1LYJgCxDKORWvC7VM4Mc= 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=XqUctygG; arc=none smtp.client-ip=91.218.175.183 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="XqUctygG" 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=1784902479; 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=JPyX50IABgrOGeZ8jbVvs7VqYszA+zBxUPlFYmDs4Ww=; b=XqUctygGDzls3X2zdXD9FyoHZu8nxm+3TFuH4vnBCDVAAWQMbZqLA+mCn38sh/TfEQ0ZLA s10TO9u3PlwXNgl/hcxJgp7Iv38YoT+n2VzH/3zDL9ntHZoOgoiZOMc+1wA/erMgOp3CyA KsIMH/Z3exbvXkLpY/FN7CjqSqceVwg= 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 0/2] bpf: Fix sleepable check for tracing prog Date: Fri, 24 Jul 2026 22:14:20 +0800 Message-ID: <20260724141422.10463-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: linux-kselftest@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. 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