From patchwork Fri Apr 7 18:35:06 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 9670199 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0A75D602A0 for ; Fri, 7 Apr 2017 18:35:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0235A28621 for ; Fri, 7 Apr 2017 18:35:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EAECF2862A; Fri, 7 Apr 2017 18:35:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 799E528621 for ; Fri, 7 Apr 2017 18:35:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B4FB06ECDE; Fri, 7 Apr 2017 18:35:13 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4D2746ECDE for ; Fri, 7 Apr 2017 18:35:12 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from nuc-i3427.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 6252625-1500050 for multiple; Fri, 07 Apr 2017 19:35:06 +0100 Received: by nuc-i3427.alporthouse.com (sSMTP sendmail emulation); Fri, 07 Apr 2017 19:35:06 +0100 Date: Fri, 7 Apr 2017 19:35:06 +0100 From: Chris Wilson To: Daniel Vetter Subject: Re: [PATCH] drm: Don't allow interruptions when opening debugfs/crc Message-ID: <20170407183506.GD24807@nuc-i3427.alporthouse.com> Mail-Followup-To: Chris Wilson , Daniel Vetter , Tomeu Vizoso , dri-devel@lists.freedesktop.org, Daniel Vetter References: <20170407111712.13962-1-chris@chris-wilson.co.uk> <20170407164246.vzk5bx3lrnaillnq@phenom.ffwll.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20170407164246.vzk5bx3lrnaillnq@phenom.ffwll.local> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: Daniel Vetter , dri-devel@lists.freedesktop.org, Tomeu Vizoso X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP On Fri, Apr 07, 2017 at 06:42:46PM +0200, Daniel Vetter wrote: > On Fri, Apr 07, 2017 at 01:55:00PM +0200, Tomeu Vizoso wrote: > > On 04/07/2017 01:17 PM, Chris Wilson wrote: > > > The code does not like to be interrupted when waiting for the first > > > vblank after opening a debugfs/crc channel, so don't. > > > > > > [66285.716870] WARNING: CPU: 1 PID: 16615 at drivers/gpu/drm/drm_debugfs_crc.c:185 crtc_crc_open+0x1d0/0x1f0 [drm] > > > [66285.716877] Modules linked in: i915 intel_powerclamp crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel cryptd intel_gtt i2c_algo_bit lpc_ich mfd_core drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops prime_numbers drm video button autofs4 sd_mod ahci libahci libata i2c_i801 scsi_mod i2c_designware_platform i2c_designware_core i2c_core > > > [66285.716929] CPU: 1 PID: 16615 Comm: kms_frontbuffer Not tainted 4.11.0-rc5+ #7 > > > [66285.716935] Hardware name: GIGABYTE GB-BXBT-1900/MZBAYAB-00, BIOS F8 03/02/2016 > > > [66285.716941] Call Trace: > > > [66285.716955] dump_stack+0x4d/0x6f > > > [66285.716966] __warn+0xc1/0xe0 > > > [66285.716975] warn_slowpath_null+0x18/0x20 > > > [66285.717004] crtc_crc_open+0x1d0/0x1f0 [drm] > > > [66285.717014] ? wake_atomic_t_function+0x50/0x50 > > > [66285.717024] full_proxy_open+0xf0/0x1b0 > > > [66285.717032] ? full_proxy_release+0x80/0x80 > > > [66285.717042] do_dentry_open.isra.17+0x14b/0x2d0 > > > [66285.717051] vfs_open+0x42/0x60 > > > [66285.717064] path_openat+0x5e7/0x13d0 > > > [66285.717074] ? refcount_dec_and_test+0x11/0x20 > > > [66285.717081] ? down_read+0xd/0x30 > > > [66285.717087] do_filp_open+0x85/0xf0 > > > [66285.717093] ? __vfs_write+0x23/0x120 > > > [66285.717100] ? __alloc_fd+0x3a/0x170 > > > [66285.717107] do_sys_open+0x11e/0x1f0 > > > [66285.717113] ? do_sys_open+0x11e/0x1f0 > > > [66285.717119] SyS_openat+0xf/0x20 > > > [66285.717125] entry_SYSCALL_64_fastpath+0x17/0x98 > > > [66285.717131] RIP: 0033:0x7f5f2235146a > > > [66285.717135] RSP: 002b:00007ffd892e6bc0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 > > > [66285.717142] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5f2235146a > > > [66285.717147] RDX: 0000000000000000 RSI: 00007ffd892e6c40 RDI: 0000000000000006 > > > [66285.717151] RBP: 00007ffd892e6b20 R08: 0000000000000000 R09: 000000000000000f > > > [66285.717156] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 > > > [66285.717161] R13: 00007ffd892e6b10 R14: 0000000000000004 R15: 00000000007e61f4 > > > > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100610 > > > Fixes: e8fa5671183c ("drm: crc: Wait for a frame before returning from open()") > > > Signed-off-by: Chris Wilson > > > Cc: Tomeu Vizoso > > > Cc: Daniel Vetter > > > > Reviewed-by: Tomeu Vizoso > > > > Sounds good to me, there isn't any good reason for the wait to be > > interruptible. > > Applied to drm-misc-next, thanks. Oh no. The other side is using wake_up_interruptible(), so only the interruptible waiters are woken and not us anymore :( Undoes the damage, or revert? -Chris diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c index aa13e734c9e5..1ec04f864437 100644 --- a/drivers/gpu/drm/drm_debugfs_crc.c +++ b/drivers/gpu/drm/drm_debugfs_crc.c @@ -354,7 +354,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, spin_unlock(&crc->lock); - wake_up_interruptible(&crc->wq); + wake_up(&crc->wq); return 0; }