From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: dri-devel <dri-devel@lists.freedesktop.org>,
LKML <linux-kernel@vger.kernel.org>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
intel-gfx <intel-gfx@lists.freedesktop.org>
Subject: Re: [Intel-gfx] drm_modes: signed integer overflow
Date: Thu, 22 Oct 2020 13:14:23 +0300 [thread overview]
Message-ID: <20201022101423.GI6112@intel.com> (raw)
In-Reply-To: <47527cdb-2eda-b5a3-d77c-3855b91a0b61@infradead.org>
On Wed, Oct 21, 2020 at 08:13:43PM -0700, Randy Dunlap wrote:
> Hi,
>
> With linux-next 20201021, when booting up, I am seeing this:
>
> [ 0.560896] UBSAN: signed-integer-overflow in ../drivers/gpu/drm/drm_modes.c:765:20
> [ 0.560903] 2376000 * 1000 cannot be represented in type 'int'
Dang. Didn't realize these new crazy >8k modes have dotclocks reaching
almost 6 GHz, which would overflow even u32. I guess we'll switch to
64bit maths. Now I wonder how many other places can hit this overflow
in practice...
> [ 0.560909] CPU: 3 PID: 7 Comm: kworker/u16:0 Not tainted 5.9.0-next-20201021 #2
> [ 0.560914] Hardware name: TOSHIBA PORTEGE R835/Portable PC, BIOS Version 4.10 01/08/2013
> [ 0.560924] Workqueue: events_unbound async_run_entry_fn
>
> [ 0.560930] Call Trace:
> [ 0.560938] dump_stack+0x5e/0x74
> [ 0.560943] ubsan_epilogue+0x9/0x45
> [ 0.560948] handle_overflow+0x8b/0x98
> [ 0.560953] ? set_track+0x3f/0xad
> [ 0.560958] __ubsan_handle_mul_overflow+0xe/0x10
> [ 0.560964] drm_mode_vrefresh+0x4a/0xbc
> [ 0.560970] initcall i915_init+0x0/0x6a returned 0 after 116076 usecs
> [ 0.560974] calling cn_proc_init+0x0/0x36 @ 1
> [ 0.560978] cea_mode_alternate_clock+0x11/0x62
> [ 0.560985] drm_match_cea_mode+0xc7/0x1e7
> [ 0.560987] initcall cn_proc_init+0x0/0x36 returned 0 after 3 usecs
> [ 0.560990] calling topology_sysfs_init+0x0/0x2d @ 1
> [ 0.561000] drm_mode_validate_ycbcr420+0xd/0x48
> [ 0.561005] drm_helper_probe_single_connector_modes+0x6db/0x7da
> [ 0.561012] drm_client_modeset_probe+0x225/0x143f
> [ 0.561018] ? bitmap_fold+0x8a/0x8a
> [ 0.561023] ? update_cfs_rq_load_avg+0x192/0x1a2
> [ 0.561029] __drm_fb_helper_initial_config_and_unlock+0x3f/0x5b7
> [ 0.561035] ? get_sd_balance_interval+0x1c/0x40
> [ 0.561040] drm_fb_helper_initial_config+0x48/0x4f
> [ 0.561047] intel_fbdev_initial_config+0x13/0x23
> [ 0.561052] async_run_entry_fn+0x89/0x15c
> [ 0.561058] process_one_work+0x15c/0x1f3
> [ 0.561064] worker_thread+0x1ac/0x25d
> [ 0.561069] ? process_scheduled_works+0x2e/0x2e
> [ 0.561074] kthread+0x10e/0x116
> [ 0.561078] ? kthread_parkme+0x1c/0x1c
> [ 0.561083] ret_from_fork+0x22/0x30
> [ 0.561087] ================================================================================
>
> --
> ~Randy
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Ville Syrjälä
Intel
next prev parent reply other threads:[~2020-10-22 10:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 3:13 drm_modes: signed integer overflow Randy Dunlap
2020-10-22 10:14 ` Ville Syrjälä [this message]
2020-10-23 15:14 ` [Intel-gfx] " Simon Ser
2020-10-23 15:27 ` Ville Syrjälä
2020-10-23 16:02 ` Simon Ser
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