From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D765C678D4 for ; Thu, 2 Mar 2023 11:17:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229455AbjCBLRC (ORCPT ); Thu, 2 Mar 2023 06:17:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229619AbjCBLRA (ORCPT ); Thu, 2 Mar 2023 06:17:00 -0500 Received: from mx1.tq-group.com (mx1.tq-group.com [93.104.207.81]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 221F230E6 for ; Thu, 2 Mar 2023 03:16:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1677755794; x=1709291794; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=oiWy5k/6xFwP/r2lA3U76koHVT0d5qDWSMq2/Bg0+Gc=; b=SELiAwL2Wnd63JlANjTng6n+oYc1DVIlsKJDyLbB1v7z0wSlFjaDM3vA RElfM4elmIdGjJg8hS9FnQFBnN1gI0BvjjXMTgd8pahSgN7JNp1E4J37j RBKlafR6uNUUlsgcW+65YXnS4XJlNUrut4/rqaaWpA9+AqaWV6vtFwbMZ 0Eg+NiyWCK3tPp1LeUWYyFE3Cy1lxWAtgFWTs1UkU8Ph8qkWL82IhjeMD t+Qd5UC2wuUgf8VMDGSqOrH+j/z0nRgjfTC6uyMD/h7yDFjz6/pOk1cfN MlndwUlfIYMf1EbcapWgo4oBXuZFPJebkH8BdVE2Q81+s+TJgbjGV9ufm w==; X-IronPort-AV: E=Sophos;i="5.98,227,1673910000"; d="scan'208";a="29422641" Received: from unknown (HELO tq-pgp-pr1.tq-net.de) ([192.168.6.15]) by mx1-pgp.tq-group.com with ESMTP; 02 Mar 2023 12:15:53 +0100 Received: from mx1.tq-group.com ([192.168.6.7]) by tq-pgp-pr1.tq-net.de (PGP Universal service); Thu, 02 Mar 2023 12:15:53 +0100 X-PGP-Universal: processed; by tq-pgp-pr1.tq-net.de on Thu, 02 Mar 2023 12:15:53 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1677755753; x=1709291753; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=oiWy5k/6xFwP/r2lA3U76koHVT0d5qDWSMq2/Bg0+Gc=; b=Hk4amG/syeQsOOFYdpKkDNSAB+za6K8HhwX9sy30UUV4QCMT8XuLkuF5 eN5bdcxtsCE9Ueksq+YuELWwHAbFFo2NxRyWOk9kFmSYCiNZkaJ2UMvo9 TH0Wj2ekHcFB4vjk4I0JvFd8Mnbtatyhb2cjqhKXDU8O9GIAFof2dj+j/ x0vPb/MX0iA1Jc+Py+Lk4GONcucy/57yj0fWDJmkxR0S1cF07IN/JcF+W zqbryUaFWzSuvvfVX3OCEAjJvNhmaP6Cm5+HkSNsT7vWbqmSBDhWfNtxT pKMf4cN92ii1UiYkcLnel/TEzhs+G3WwI39UPBY5aQpnFnFtj3bpDxqEx w==; X-IronPort-AV: E=Sophos;i="5.98,227,1673910000"; d="scan'208";a="29422640" Received: from vtuxmail01.tq-net.de ([10.115.0.20]) by mx1.tq-group.com with ESMTP; 02 Mar 2023 12:15:53 +0100 Received: from steina-w.localnet (unknown [10.123.53.21]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by vtuxmail01.tq-net.de (Postfix) with ESMTPSA id 21C64280056; Thu, 2 Mar 2023 12:15:53 +0100 (CET) From: Alexander Stein To: NXP Linux Team , Emanuele Ghidoli Cc: Pengutronix Kernel Team , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Dong Aisheng , Shawn Guo , Sascha Hauer , Fabio Estevam Subject: Re: [PATCH 1/2] i2c: imx-lpi2c: clean rx/tx buffers upon new message Date: Thu, 02 Mar 2023 12:15:51 +0100 Message-ID: <2672031.mvXUDI8C0e@steina-w> Organization: TQ-Systems GmbH In-Reply-To: <4d06ffe5-3ff6-241e-b35b-794c075f288e@gmail.com> References: <20230130153247.445027-1-alexander.stein@ew.tq-group.com> <4d06ffe5-3ff6-241e-b35b-794c075f288e@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Hi Emanuele, Am Donnerstag, 2. M=E4rz 2023, 12:06:18 CET schrieb Emanuele Ghidoli: > On 30/01/2023 16:32, Alexander Stein wrote: > > When start sending a new message clear the Rx & Tx buffer pointers in > > order to avoid using stale pointers. > >=20 > > Signed-off-by: Alexander Stein > > --- > > I noticed an ambigous stack corruption once my rtc-pcf85063 driver prob= es. > >=20 > > [ 2.695684] Kernel panic - not syncing: stack-protector: Kernel stack > > is corrupted in: pcf85063_rtc_read_time+0x10/0x100 [ 2.706669] CPU: 1 > > PID: 63 Comm: kworker/u8:2 Not tainted 6.2.0-rc6-next-20230130+ #1185 > > ca067559321ae817c063baccdba80d328f10f73 [ 2.718331] Hardware name: > > TQ-Systems i.MX8QXP TQMa8XQP on MBa8Xx (DT) [ 2.724866] Workqueue: > > events_unbound deferred_probe_work_func > > [ 2.730712] Call trace: > > [ 2.733161] dump_backtrace+0x9c/0x11c > > [ 2.736914] show_stack+0x14/0x1c > > [ 2.740232] dump_stack_lvl+0x5c/0x78 > > [ 2.743907] dump_stack+0x14/0x1c > > [ 2.747225] panic+0x34c/0x39c > > [ 2.750283] __ktime_get_real_seconds+0x0/0xc > > [ 2.754653] pcf85063_ioctl+0x0/0xf0 > > [ 2.758232] __rtc_read_time+0x44/0x114 > > [ 2.762081] __rtc_read_alarm+0x258/0x460 > > [ 2.766095] __devm_rtc_register_device+0x174/0x2b4 > > [ 2.770986] pcf85063_probe+0x258/0x4d4 > > [ 2.774825] i2c_device_probe+0x100/0x33c > >=20 > > The backtrace did not indicate the actual cause of it. Checking the code > > the RTC driver seemed to be ok, so it has to be in the i2c bus driver. = At > > some point I noticed that I see both Rx and Tx interrupts at the same > > time, which is odd. Also both rx_buf and tx_buf was set simultaneously. > > Clearly a bug to me. > > Clearing the buffer pointers upon each new i2c message triggered a NULL > > pointer dereference: > >=20 > > [ 2.694923] Unable to handle kernel NULL pointer dereference at virt= ual > > address 0000000000000001 [ 2.703730] Mem abort info: > > [ 2.706525] ESR =3D 0x0000000096000004 > > [ 2.710278] EC =3D 0x25: DABT (current EL), IL =3D 32 bits > > [ 2.715595] SET =3D 0, FnV =3D 0 > > [ 2.718653] EA =3D 0, S1PTW =3D 0 > > [ 2.721798] FSC =3D 0x04: level 0 translation fault > > [ 2.726680] Data abort info: > > [ 2.729556] ISV =3D 0, ISS =3D 0x00000004 > > [ 2.733387] CM =3D 0, WnR =3D 0 > > [ 2.736358] [0000000000000001] user address but active_mm is swapper > > [ 2.742719] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP > > [ 2.748990] Modules linked in: > > [ 2.752051] CPU: 0 PID: 0 Comm: swapper/0 Not tainted > > 6.2.0-rc6-next-20230130+ #1184 44a8abebca6bfabc93e20ac52bce 47da7f92cec1 > > [ 2.763368] Hardware name: TQ-Systems i.MX8QXP TQMa8XQP on MBa8Xx (D= T) > > [ 2.769902] pstate: 800000c5 (Nzcv daIF -PAN -UAO -TCO -DIT -SSBS > > BTYPE=3D--) [ 2.776868] pc : lpi2c_imx_write_txfifo+0x44/0xb0 > > [ 2.781585] lr : lpi2c_imx_isr+0x60/0x8c > > [ 2.785512] sp : ffff800008003ef0 > > [ 2.788831] x29: ffff800008003ef0 x28: ffff8000099c1ec0 x27: > > 00000000bfe632c8 [ 2.795980] x26: 0000000000000000 x25: > > ffff800009b935ed x24: ffff800009a4d4c0 [ 2.803130] x23: > > ffff00000365e800 x22: 0000000000000128 x21: 0000000000000000 [ =20 > > 2.810280] x20: ffff0000033f4080 x19: 0000000003000103 x18: > > 0000000000000000 [ 2.817430] x17: ffff80003688a000 x16: > > ffff800008000000 x15: 0000000000000000 [ 2.824579] x14: > > 0000000000000000 x13: ffff8000099d1db8 x12: 0000000000000000 [ =20 > > 2.831729] x11: ffff800009503180 x10: 0000000000000a80 x9 : > > ffff8000099b3d20 [ 2.838879] x8 : ffff8000099c29a0 x7 : > > 00000000000000c0 x6 : ffff000002838028 [ 2.846029] x5 : > > 0000000000000002 x4 : 0000000000000000 x3 : 0000000000000000 [ =20 > > 2.849626] imx-scu system-controller: RPC send msg timeout > > [ 2.853178] x2 : ffff800009c88060 x1 : 0000000000000001 x0 : > > ffff0000033f4080 [ 2.858764] enet1: failed to power off resource 252 > > ret -110 > > [ 2.865897] Call trace: > > [ 2.865901] lpi2c_imx_write_txfifo+0x44/0xb0 > > [ 2.878443] __handle_irq_event_percpu+0x5c/0x188 > > [ 2.883151] handle_irq_event+0x48/0xb0 > >=20 > > $ ./scripts/faddr2line build_arm64/vmlinux > > lpi2c_imx_write_txfifo+0x44/0xb0 > > lpi2c_imx_write_txfifo+0x44/0xb0: > > lpi2c_imx_write_txfifo at drivers/i2c/busses/i2c-imx-lpi2c.c:364 > >=20 > > This now clearly pinpoints the wrong access which previously corrupted = the > > stack. The error leading to this wrong access is addressed in the > > following patch. > >=20 > > drivers/i2c/busses/i2c-imx-lpi2c.c | 2 ++ > > 1 file changed, 2 insertions(+) > >=20 > > diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c > > b/drivers/i2c/busses/i2c-imx-lpi2c.c index 188f2a36d2fd..c6d0225246e6 > > 100644 > > --- a/drivers/i2c/busses/i2c-imx-lpi2c.c > > +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c > > @@ -463,6 +463,8 @@ static int lpi2c_imx_xfer(struct i2c_adapter *adapt= er, > >=20 > > if (num =3D=3D 1 && msgs[0].len =3D=3D 0) > > =09 > > goto stop; > >=20 > > + lpi2c_imx->rx_buf =3D NULL; > > + lpi2c_imx->tx_buf =3D NULL; > >=20 > > lpi2c_imx->delivered =3D 0; > > lpi2c_imx->msglen =3D msgs[i].len; > > init_completion(&lpi2c_imx->complete); >=20 > Hello, > I have same problem with rtc-ds1307 driver and NXP imx8x (using > ic2-imx-lpi2c.c bus driver). I do not have the full stack trace but I'm > sure is very similar: > [ 10.750015] Kernel panic - not syncing: stack-protector: Kernel stack = is > corrupted in: ds1307_get_time+0x2a4/0x2c4 [rtc_ds1307] >=20 > Your patches are fixing this too and they seem good to me. > About the [2/2] patch your approach sound better to me than the downstream > approach. >=20 > Emanuele Ghidoli Thanks for the feedback. Could you provide then a Tested-by tag? Best regards, Alexander =2D-=20 TQ-Systems GmbH | M=FChlstra=DFe 2, Gut Delling | 82229 Seefeld, Germany Amtsgericht M=FCnchen, HRB 105018 Gesch=E4ftsf=FChrer: Detlef Schneider, R=FCdiger Stahl, Stefan Schneider http://www.tq-group.com/