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 B50EB318B96; Thu, 28 May 2026 20:51:10 +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=1780001471; cv=none; b=kBgZ621zlBZBvstx/ReEojhT4mnuCxpqQ/rJ4IRLscxxu078z4nGfO7TdFn97rnhQFWGdzKZFh2kD+NCsjxGHsFVqp6V23HzfZ9MQsyQUaHpofjPIMfS3zDcHGzkL2z5/mNmht4erk5bprQ+RGs9vN6ksn/lFfN71EUyAph43Qo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780001471; c=relaxed/simple; bh=I1GcGmZGH2AERGxFstdO/MuLIF6fPdput2Zq5N+gU9U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Y3jRSEFqVKICRNgRNRVHAF7I/2vsZwWqveyl0hwli2ljNsuO9T5Fl4kRsWjZxTy8HN0Ow0NK31IaSHcccco/l+Y3+2tWb+lsAqO5wqDTnD7FfJ3xyCSUrP7S6RgPNf5y8cQKpPnsrugAzvY4D5NwAlNGP96R5zIPwhBwHCZopBQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=G/Kt3Cqv; 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="G/Kt3Cqv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 238591F000E9; Thu, 28 May 2026 20:51:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780001470; bh=NfoDfHaWRFOtKM+Dml/6xCbPuUMfg6I3eau8CnNUkhw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=G/Kt3CqvN2FnsO+CH23hqxWfD8M851xudELSWr1JTogJrRWYZoEAzEiVB9byAkrqf InMi4r7V9ly2wgqp+FfXgWTG9vX9OCpvKqTLjSwU0ig7GAlesnksKk7CywkMpXHnNo wjPJ/WLEEDca/EKL9pLGSq6HXm8LW3raEYZ1kgko= 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 6.6 138/186] net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint Date: Thu, 28 May 2026 21:50:18 +0200 Message-ID: <20260528194932.677162024@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260528194928.941004471@linuxfoundation.org> References: <20260528194928.941004471@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 6.6-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