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 4978B30E853; Sat, 30 May 2026 17:34:37 +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=1780162478; cv=none; b=FiN5Hk0yhAFf5nI4Ayc5G0WPuxyihFb5NTHxh1oRLg0wq0B4byFR3g2UY3mQPQ4617pSOaruU6bIA152RvyOgFEsnxi6Q97avrivo6ynJFx4gJwWLWJvYtlMV62hfbaOQmuoF6hzeLeY9OuMwR/NkKDBWPOb5FnAuOZs/A1WgJs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780162478; c=relaxed/simple; bh=qVM0edbnv7dM3hFfw2tvC8DtsTfCfh3A1+yOTN+31Qg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qA8pTvwV6zpO8+VMq3Evm2ErZu9kD2y/912c+OBqYDcZ0x7QOTjfAH1ZHMANkOMKTUogE+RFZnFdPwSvj6t5MzKsNpnf6/cRSDIWvPt5R6UM8zdk0F5POxyenQGLJkYRW2bN/LpnImD3wTCd3b5ZjnneHQQpvUlwz0eKGaIx2LE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=WevsYB15; 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="WevsYB15" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8CA0D1F00893; Sat, 30 May 2026 17:34:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780162477; bh=frS2MlwsGQBjvtiwIwpTHgecObeSZcPeNjke3CD4PlE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WevsYB15kUUlVxTKiT/P0UzrBoiwQ76tLnPujtc9OOWbIHOk+nEad/sgPm5ToPq3V MkS2UNAlKfA4knBgzy5NFsgAiTE7HHgaEPfPkZucxvHUp048tPTH30zhuSVYHtGz4a lBHURTqmzEMKIiAIidOO6NBnraXS4MmIGCVeMokQ= 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 6.1 932/969] net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint Date: Sat, 30 May 2026 18:07:36 +0200 Message-ID: <20260530160326.481631517@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160300.485627683@linuxfoundation.org> References: <20260530160300.485627683@linuxfoundation.org> User-Agent: quilt/0.69 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 6.1-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 9fc5e586d24ab..380451912c4f1 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