From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 135B81C3318; Thu, 28 May 2026 20:27:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780000030; cv=none; b=ORKL2rHKvfKDWUEr4hqdElg+AsjwcmbE+xCDZXAVCj1hVAiJ2sCqAQr1O8FzsVpQmLntAF+n1i/AfeKRAgSIEcegZRG1imJztKV81l5kginvVKa2CU8h0KxLRoer5580vFAsOgskIfzMHn/hW2W9KmXbzvq2+nmDCtZ1MgnrR2g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780000030; c=relaxed/simple; bh=LG1QfqsCjk+BJE6pojD9ZMTbCLSRvNnbGmhJOxRPTgI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mqznc3vXrgrZ04K2a2uXmzf7VlnZ66lZGpzbf5ZH2vMvZdYlteMghZAPeSTodpMkVtveNXiXkLdHego7thPGt02FqqNu8qKpnGkIldNy/WzMGtA/bQhWt5tbSWPLgtjd9y2acxNm4SKBZO67kHacigS2cetemH1+3FVWWZhiENc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EV3rwSXt; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EV3rwSXt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 779071F00A3F; Thu, 28 May 2026 20:27:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780000029; bh=tKPnmL0/pKSFzSbjdYdaOdUwiGKjBkcjVEaoNIdWQb8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EV3rwSXtdhWFx9ojZW/1agtvOeNv8bckZLN4pEySWMj9emMKmDVfDkA8sUL0KSvVL gF708Fpdj4JuaicROAwAz10qln7KJwHg6+GhvK4zRY9XMP5wU2qnFKKBbgfAofRLD1 u06li9KDmSNxZPthWSIPioUhTvYYZArs7kV8ETNQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Dust Li , Sidraya Jayagond , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 270/377] net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint Date: Thu, 28 May 2026 21:48:28 +0200 Message-ID: <20260528194646.185492614@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260528194638.371537336@linuxfoundation.org> References: <20260528194638.371537336@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit 7bf563badd37cb796df5477d2b78bb64148a1268 ] The smc_msg_event tracepoint class, shared by smc_tx_sendmsg and smc_rx_recvmsg, unconditionally dereferences smc->conn.lnk: __string(name, smc->conn.lnk->ibname) conn->lnk is only set for SMC-R; for SMC-D it is NULL. Other code on these paths already handles this (e.g. !conn->lnk in SMC_STAT_RMB_TX_SIZE_SMALL()). With the tracepoint enabled, the first sendmsg()/recvmsg() on an SMC-D socket crashes: Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [...] RIP: 0010:strlen+0x1e/0xa0 Call Trace: trace_event_raw_event_smc_msg_event (net/smc/smc_tracepoint.h:44) smc_rx_recvmsg (net/smc/smc_rx.c:515) smc_recvmsg (net/smc/af_smc.c:2859) __sys_recvfrom (net/socket.c:2315) __x64_sys_recvfrom (net/socket.c:2326) do_syscall_64 The faulting address 0x3e0 is offsetof(struct smc_link, ibname), confirming the NULL ->lnk deref. Enabling the tracepoint requires root, but the trigger itself is unprivileged: socket(AF_SMC, ...) has no capability check, and SMC-D negotiation needs no admin step on s390 or on x86 with the loopback ISM device loaded. Log an empty device name for SMC-D instead of dereferencing NULL. Fixes: aff3083f10bf ("net/smc: Introduce tracepoints for tx and rx msg") Reported-by: Weiming Shi Signed-off-by: Xiang Mei Reviewed-by: Dust Li Reviewed-by: Sidraya Jayagond Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/smc/smc_tracepoint.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/smc/smc_tracepoint.h b/net/smc/smc_tracepoint.h index a9a6e3c1113aa..53da84f57fd6f 100644 --- a/net/smc/smc_tracepoint.h +++ b/net/smc/smc_tracepoint.h @@ -51,7 +51,7 @@ DECLARE_EVENT_CLASS(smc_msg_event, __field(const void *, smc) __field(u64, net_cookie) __field(size_t, len) - __string(name, smc->conn.lnk->ibname) + __string(name, smc->conn.lnk ? smc->conn.lnk->ibname : "") ), TP_fast_assign( -- 2.53.0