From 1c3415a06b1016a596bfe59e0cfee56c773aa958 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Thu, 5 Jan 2017 14:14:54 -0800 Subject: [PATCH] Input: elants_i2c - avoid divide by 0 errors on bad touchscreen data The following crash may be seen if bad data is received from the touchscreen. [ 2189.425150] elants_i2c i2c-ELAN0001:00: unknown packet ff ff ff ff [ 2189.430738] divide error: 0000 [#1] PREEMPT SMP [ 2189.434679] gsmi: Log Shutdown Reason 0x03 [ 2189.434689] Modules linked in: ip6t_REJECT nf_reject_ipv6 rfcomm evdi uinput uvcvideo cmac videobuf2_vmalloc videobuf2_memops snd_hda_codec_hdmi i2c_dev videobuf2_core snd_soc_sst_cht_bsw_rt5645 snd_hda_intel snd_intel_sst_acpi btusb btrtl btbcm btintel bluetooth snd_soc_sst_acpi snd_hda_codec snd_intel_sst_core snd_hwdep snd_soc_sst_mfld_platform snd_hda_core snd_soc_rt5645 memconsole_x86_legacy memconsole zram snd_soc_rl6231 fuse ip6table_filter iwlmvm iwlwifi iwl7000_mac80211 cfg80211 iio_trig_sysfs joydev cros_ec_sensors cros_ec_sensors_core industrialio_triggered_buffer kfifo_buf industrialio snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device ppp_async ppp_generic slhc tun [ 2189.434866] CPU: 0 PID: 106 Comm: irq/184-ELAN000 Tainted: G W 3.18.0-13101-g57e8190 #1 [ 2189.434883] Hardware name: GOOGLE Ultima, BIOS Google_Ultima.7287.131.43 07/20/2016 [ 2189.434898] task: ffff88017a0b6d80 ti: ffff88017a2bc000 task.ti: ffff88017a2bc000 [ 2189.434913] RIP: 0010:[] [] elants_i2c_irq+0x190/0x200 [ 2189.434937] RSP: 0018:ffff88017a2bfd98 EFLAGS: 00010293 [ 2189.434948] RAX: 0000000000000000 RBX: ffff88017a967828 RCX: ffff88017a9678e8 [ 2189.434962] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000000 [ 2189.434975] RBP: ffff88017a2bfdd8 R08: 00000000000003e8 R09: 0000000000000000 [ 2189.434989] R10: 0000000000000000 R11: 000000000044a2bd R12: ffff88017a991800 [ 2189.435001] R13: ffffffffbe8a2a53 R14: ffff88017a0b6d80 R15: ffff88017a0b6d80 [ 2189.435011] FS: 0000000000000000(0000) GS:ffff88017fc00000(0000) knlGS:0000000000000000 [ 2189.435022] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 2189.435030] CR2: 00007f678d94b000 CR3: 000000003f41a000 CR4: 00000000001007f0 [ 2189.435039] Stack: [ 2189.435044] ffff88017a2bfda8 ffff88017a9678e8 646464647a2bfdd8 0000000006e09574 [ 2189.435060] 0000000000000000 ffff88017a088b80 ffff88017a921000 ffffffffbe8a2a53 [ 2189.435074] ffff88017a2bfe08 ffffffffbe8a2a73 ffff88017a0b6d80 0000000006e09574 [ 2189.435089] Call Trace: [ 2189.435101] [] ? irq_thread_dtor+0xa9/0xa9 [ 2189.435112] [] irq_thread_fn+0x20/0x40 [ 2189.435123] [] irq_thread+0x14e/0x222 [ 2189.435135] [] ? __schedule+0x3b3/0x57a [ 2189.435145] [] ? wake_threads_waitq+0x2d/0x2d [ 2189.435156] [] ? irq_thread_fn+0x40/0x40 [ 2189.435168] [] kthread+0x10e/0x116 [ 2189.435178] [] ? __kthread_parkme+0x67/0x67 [ 2189.435189] [] ret_from_fork+0x7c/0xb0 [ 2189.435199] [] ? __kthread_parkme+0x67/0x67 [ 2189.435208] Code: ff ff eb 73 0f b6 bb c1 00 00 00 83 ff 03 7e 13 49 8d 7c 24 20 ba 04 00 00 00 48 c7 c6 8a cd 21 bf eb 4d 0f b6 83 c2 00 00 00 99 ff 83 f8 37 75 15 48 6b f7 37 4c 8d a3 c4 00 00 00 4c 8d ac [ 2189.435312] RIP [] elants_i2c_irq+0x190/0x200 [ 2189.435323] RSP [ 2189.435350] ---[ end trace f4945345a75d96dd ]--- [ 2189.443841] Kernel panic - not syncing: Fatal exception [ 2189.444307] Kernel Offset: 0x3d800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 2189.444519] gsmi: Log Shutdown Reason 0x02 The problem was seen with a 3.18 based kernel, but there is no reason to believe that the upstream code is safe. Fixes: 66aee90088da2 ("Input: add support for Elan eKTH I2C touchscreens") Signed-off-by: Guenter Roeck Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/elants_i2c.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c index 02aec284deca..3e6003d32e56 100644 --- a/drivers/input/touchscreen/elants_i2c.c +++ b/drivers/input/touchscreen/elants_i2c.c @@ -914,9 +914,9 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev) case QUEUE_HEADER_NORMAL: report_count = ts->buf[FW_HDR_COUNT]; - if (report_count > 3) { + if (report_count == 0 || report_count > 3) { dev_err(&client->dev, - "too large report count: %*ph\n", + "bad report count: %*ph\n", HEADER_SIZE, ts->buf); break; } -- 2.20.1