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 3D35E2EA14E; Tue, 17 Jun 2025 16:19:12 +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=1750177152; cv=none; b=MEHnPUYtgc95FjorcocoEhVjzL4EWjsZ2IzOZuAMd0CxZn2GVOf04+huHM4OOw3WTkiFiGjabhaHuwlTjkwKW21ICZZWT94aIxRwspTe3XaIV4hjS/xzcan+zVVtE0FmKEzgffVZ6LcuaYVzrsqHYmRqz8vHbMpPL3MlrVFFVFE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750177152; c=relaxed/simple; bh=ibntUliKNRPXs6uwzU0A1mLRqiaAvmFCxk6YKHA6Fyc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H6qzEhhR33Sw6wBIqzZ9QNptl30aLbusyfoZNPNT0kWwoM8rLafOUjlDVbkyKwkTL7oSg1QQJJF2O8zk1TGQYM9l997UIWVwsJp6T6+knokGBrChLsZteEJElmCWs9n1vQzN/8MiXALDSMq5ba2cvgiwC4SIu6FmGOArhhedJuk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ybt7Viar; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ybt7Viar" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4F5DC4CEE3; Tue, 17 Jun 2025 16:19:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750177152; bh=ibntUliKNRPXs6uwzU0A1mLRqiaAvmFCxk6YKHA6Fyc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ybt7Viar56NlC9TL7nvCAKWdtyYdXGpsvkKKyvSsuYs98fFHahS+QASxoBNBwXDPn dgdY+A711F9XFGU7Do28NtKrgNONilEgcYANpnseT2BOCOHpVnXa/AIMRlRLafi+zi 5cBEHlgXxpqat6/1yUqTGslEUi3Hi20fClJdgs5A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ilya Leoshkevich , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.15 266/780] s390/bpf: Store backchain even for leaf progs Date: Tue, 17 Jun 2025 17:19:34 +0200 Message-ID: <20250617152502.293146073@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250617152451.485330293@linuxfoundation.org> References: <20250617152451.485330293@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ilya Leoshkevich [ Upstream commit 5f55f2168432298f5a55294831ab6a76a10cb3c3 ] Currently a crash in a leaf prog (caused by a bug) produces the following call trace: [<000003ff600ebf00>] bpf_prog_6df0139e1fbf2789_fentry+0x20/0x78 [<0000000000000000>] 0x0 This is because leaf progs do not store backchain. Fix by making all progs do it. This is what GCC and Clang-generated code does as well. Now the call trace looks like this: [<000003ff600eb0f2>] bpf_prog_6df0139e1fbf2789_fentry+0x2a/0x80 [<000003ff600ed096>] bpf_trampoline_201863462940+0x96/0xf4 [<000003ff600e3a40>] bpf_prog_05f379658fdd72f2_classifier_0+0x58/0xc0 [<000003ffe0aef070>] bpf_test_run+0x210/0x390 [<000003ffe0af0dc2>] bpf_prog_test_run_skb+0x25a/0x668 [<000003ffe038a90e>] __sys_bpf+0xa46/0xdb0 [<000003ffe038ad0c>] __s390x_sys_bpf+0x44/0x50 [<000003ffe0defea8>] __do_syscall+0x150/0x280 [<000003ffe0e01d5c>] system_call+0x74/0x98 Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Ilya Leoshkevich Link: https://lore.kernel.org/r/20250512122717.54878-1-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- arch/s390/net/bpf_jit_comp.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 0776dfde2dba9..945106b5562db 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -605,17 +605,15 @@ static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp, } /* Setup stack and backchain */ if (is_first_pass(jit) || (jit->seen & SEEN_STACK)) { - if (is_first_pass(jit) || (jit->seen & SEEN_FUNC)) - /* lgr %w1,%r15 (backchain) */ - EMIT4(0xb9040000, REG_W1, REG_15); + /* lgr %w1,%r15 (backchain) */ + EMIT4(0xb9040000, REG_W1, REG_15); /* la %bfp,STK_160_UNUSED(%r15) (BPF frame pointer) */ EMIT4_DISP(0x41000000, BPF_REG_FP, REG_15, STK_160_UNUSED); /* aghi %r15,-STK_OFF */ EMIT4_IMM(0xa70b0000, REG_15, -(STK_OFF + stack_depth)); - if (is_first_pass(jit) || (jit->seen & SEEN_FUNC)) - /* stg %w1,152(%r15) (backchain) */ - EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, - REG_15, 152); + /* stg %w1,152(%r15) (backchain) */ + EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, + REG_15, 152); } } -- 2.39.5