Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756750Ab2KZRnK (ORCPT ); Mon, 26 Nov 2012 12:43:10 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:47776 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933417Ab2KZRKJ (ORCPT ); Mon, 26 Nov 2012 12:10:09 -0500 From: Herton Ronaldo Krzesinski To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Stefano Babic , Felipe Balbi , Herton Ronaldo Krzesinski Subject: [PATCH 164/270] usb: musb: am35xx: drop spurious unplugging a device Date: Mon, 26 Nov 2012 14:57:34 -0200 Message-Id: <1353949160-26803-165-git-send-email-herton.krzesinski@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1353949160-26803-1-git-send-email-herton.krzesinski@canonical.com> References: <1353949160-26803-1-git-send-email-herton.krzesinski@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2697 Lines: 71 3.5.7u1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefano Babic commit 6ff1f3d3bd7c69c62ca5773b1b684bce42eff06a upstream. On AM3517, tx and rx interrupt are detected together with the disconnect event. This generates a kernel panic in musb_interrupt, because rx / tx are handled after disconnect. This issue was seen on a Technexion's TAM3517 SOM. Unplugging a device, tx / rx interrupts together with disconnect are detected. This brings to kernel panic like this: [ 68.526153] Unable to handle kernel NULL pointer dereference at virtual address 00000011 [ 68.534698] pgd = c0004000 [ 68.537536] [00000011] *pgd=00000000 [ 68.541351] Internal error: Oops: 17 [#1] ARM [ 68.545928] Modules linked in: [ 68.549163] CPU: 0 Not tainted (3.6.0-rc5-00020-g9e05905 #178) [ 68.555694] PC is at rxstate+0x8/0xdc [ 68.559539] LR is at musb_interrupt+0x98/0x858 [ 68.564239] pc : [] lr : [] psr: 40000193 [ 68.564239] sp : ce83fb40 ip : d0906410 fp : 00000000 [ 68.576293] r10: 00000000 r9 : cf3b0e40 r8 : 00000002 [ 68.581817] r7 : 00000019 r6 : 00000001 r5 : 00000001 r4 : 000000d4 [ 68.588684] r3 : 00000000 r2 : 00000000 r1 : ffffffcc r0 : cf23c108 [ 68.595550] Flags: nZcv IRQs off FIQs on Mode SVC_32 ISA ARM Segment ke Note: this behavior is not seen with a USB hub, while it is easy to reproduce connecting a USB-pen directly to the USB-A of the board. Drop tx / rx interrupts if disconnect is detected. Signed-off-by: Stefano Babic CC: Felipe Balbi Tested-by: Dmitry Lifshitz Tested-by: Igor Grinberg Signed-off-by: Felipe Balbi Signed-off-by: Herton Ronaldo Krzesinski --- drivers/usb/musb/am35x.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/usb/musb/am35x.c b/drivers/usb/musb/am35x.c index 9f3eda9..340cff9 100644 --- a/drivers/usb/musb/am35x.c +++ b/drivers/usb/musb/am35x.c @@ -311,6 +311,12 @@ static irqreturn_t am35x_musb_interrupt(int irq, void *hci) ret = IRQ_HANDLED; } + /* Drop spurious RX and TX if device is disconnected */ + if (musb->int_usb & MUSB_INTR_DISCONNECT) { + musb->int_tx = 0; + musb->int_rx = 0; + } + if (musb->int_tx || musb->int_rx || musb->int_usb) ret |= musb_interrupt(musb); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/