Attachment 37158 Details for Bug 28811 – Prevent the OOPS from flipping an unbound fb

[patch] Prevent the OOPS from flipping an unbound fb

0001-drm-Return-EBUSY-if-the-framebuffer-is-unbound-when-.patch (text/plain), 3.33 KB, created by Chris Wilson on 2010-07-17 12:24:48 UTC

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Creator: Chris Wilson

Created: 2010-07-17 12:24:48 UTC

Size: 3.33 KB

patch

obsolete

>From b6dc5d15fd692900663fd4319fcc462441cee848 Mon Sep 17 00:00:00 2001
>From: Chris Wilson <chris@chris-wilson.co.uk>
>Date: Sat, 17 Jul 2010 20:06:54 +0100
>Subject: [PATCH 1/2] drm: Return EBUSY if the framebuffer is unbound when flipping.
>
>It looks like there is a race condition between unbinding a framebuffer
>on a hotplug event and user space trying to flip:
>
>BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
>IP: [<ffffffffa008c7d3>] intel_crtc_page_flip+0xc9/0x39c [i915]
>PGD 114724067 PUD 1145bd067 PMD 0
>Oops: 0000 [#1] SMP
>Pid: 10954, comm: X Not tainted 2.6.35-rc5_stable_20100714+ #1
>P5Q-EM/P5Q-EM
>RIP: 0010:[<ffffffffa008c7d3>]  [<ffffffffa008c7d3>]
>intel_crtc_page_flip+0xc9/0x39c [i915]
>RSP: 0018:ffff880114927cc8  EFLAGS: 00010282
>RAX: 0000000000000000 RBX: ffff88012df48320 RCX: ffff88010c945600
>RDX: ffff880001a109c8 RSI: ffff88010c945840 RDI: ffff88012df48320
>RBP: ffff880114927d18 R08: ffff88012df48280 R09: ffff88012df48320
>R10: 0000000003c2e0b0 R11: 0000000000003246 R12: ffff88010c945840
>R13: ffff88012df48000 R14: 0000000000000060 R15: ffff88012dbb8000
>FS:  00007f9e6078e830(0000) GS:ffff880001a00000(0000)
>knlGS:0000000000000000
>CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
>CR2: 0000000000000058 CR3: 00000001177a8000 CR4: 00000000000406f0
>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>Process X (pid: 10954, threadinfo ffff880114926000, task
>ffff88012a4a1690)
>Stack:
> ffff88010c945600 ffff880115b176c0 ffff88012db10000 0000000000000246
><0> fffffff40006101c ffff88010c945600 00000000ffffffea ffff88010c945600
><0> ffff88012df48320 ffff88011b4b6780 ffff880114927d78 ffffffffa003bd0e
>Call Trace:
> [<ffffffffa003bd0e>] drm_mode_page_flip_ioctl+0x1bc/0x214 [drm]
> [<ffffffffa00311fc>] drm_ioctl+0x25e/0x35e [drm]
> [<ffffffffa003bb52>] ? drm_mode_page_flip_ioctl+0x0/0x214 [drm]
> [<ffffffff810f1c3c>] vfs_ioctl+0x2a/0x9e
> [<ffffffff810f227e>] do_vfs_ioctl+0x531/0x565
> [<ffffffff810f2307>] sys_ioctl+0x55/0x77
> [<ffffffff810e56d6>] ? sys_read+0x47/0x6f
> [<ffffffff81002a2b>] system_call_fastpath+0x16/0x1b
>Code: 45 d4 f4 ff ff ff 0f 84 e0 02 00 00 48 8b 4d b0 49 8d 9d 20 03 00 00 48
>89 df 49 89 4c 24 38 49 8b 07 49 89 44 24 20 49 8b 47 20 <48> 8b 40 58 49 c7 04
>24 00 00 00 00 49 c7 44 24 18 a9 a5 08 a0
>RIP  [<ffffffffa008c7d3>] intel_crtc_page_flip+0xc9/0x39c [i915]
> RSP <ffff880114927cc8>
>CR2: 0000000000000058
>
>References:
>
>  Bug 28811 - [page-flipping] GPU hang when modeset after unplugging
>              another monitor (under compiz)
>  https://bugs.freedesktop.org/show_bug.cgi?id=28811
>
>Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
>Cc: Dave Airlie <airlied@redhat.com>
>---
> drivers/gpu/drm/drm_crtc.c |    9 +++++++++
> 1 files changed, 9 insertions(+), 0 deletions(-)
>
>diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
>index 0371a2f..d9d5e9f 100644
>--- a/drivers/gpu/drm/drm_crtc.c
>+++ b/drivers/gpu/drm/drm_crtc.c
>@@ -2610,6 +2610,15 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
> 		goto out;
> 	crtc = obj_to_crtc(obj);
> 
>+	if (crtc->fb == NULL) {
>+		/* The framebuffer is currently unbound, presumably
>+		 * due to a hotplug event, that userspace has not
>+		 * yet discovered.
>+		 */
>+		ret = -EBUSY;
>+		goto out;
>+	}
>+
> 	if (crtc->funcs->page_flip == NULL)
> 		goto out;
> 
>-- 
>1.7.1
>

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Attachments on bug 28811: 36599 | 36600 | 36601 | 36602 | 36666 | 36718 | 36719 | 37059 | 37060 | 37061 | 37158

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