From 1510dd5954be5070e46b155eb32362dc73d9e9cb Mon Sep 17 00:00:00 2001 From: Éric Piel Date: Mon, 31 Oct 2011 17:10:31 -0700 Subject: lis3lv02d: avoid divide by zero due to unchecked MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit After an "unexpected" reboot, I found this Oops in my logs: divide error: 0000 [#1] PREEMPT SMP=20 CPU 0=20 Modules linked in: lis3lv02d hp_wmi input_polldev [...] Pid: 390, comm: modprobe Tainted: G C 2.6.39-rc7-wl+=20 RIP: 0010:[] [] lis3lv02d_poweron+0x4e/0x94 [lis3lv02d] RSP: 0018:ffff8801d6407cf8 EFLAGS: 00010246 RAX: 0000000000000bb8 RBX: ffffffffa014e000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffea00066e4708 RDI: ffff8801df002700 RBP: ffff8801d6407d18 R08: ffffea00066c5a30 R09: ffffffff812498c9 R10: ffff8801d7bfcea0 R11: ffff8801d7bfce10 R12: 0000000000000bb8 R13: 00000000ffffffda R14: ffffffffa0154120 R15: ffffffffa0154030 =46S: 00007fc0705db700(0000) GS:ffff8801dfa00000(0000) knlGS:0 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f33549174f0 CR3: 00000001d65c9000 CR4: 00000000000406f0 Process modprobe (pid: 390, threadinfo ffff8801d6406000, task ffff8801d6b40= 000) Stack: ffffffffa0154120 62ffffffa0154030 ffffffffa014e000 00000000ffffffea ffff8801d6407d58 ffffffffa014bcc1 0000000000000000 0000000000000048 ffff8801d8bae800 00000000ffffffea 00000000ffffffda ffffffffa0154120 Call Trace: [] lis3lv02d_init_device+0x1ce/0x496 [lis3lv02d] [] lis3lv02d_add+0x10f/0x17c [hp_accel] [] acpi_device_probe+0x49/0x117 [...] Code: 3a 75 06 80 4d ef 50 eb 04 80 4d ef 40 0f b6 55 ef be 21 00 00 00 48 89 df ff 53 18 44 8b 63 6c e8 3e fc ff ff 89 c1 44 89 e0 99 f9 89 c7 e8 93 82 ef e0 48 83 7b 30 00 74 2d 45 31 e4 80 7b=20 RIP [] lis3lv02d_poweron+0x4e/0x94 [lis3lv02d] RSP >From my POV, it looks like the hardware is not working as expected and returns a bogus data rate. The driver doesn't check the result and directly uses it as some sort of divisor in some places: msleep(lis3->pwron_delay / lis3lv02d_get_odr()); Under this circumstances, this could very well cause the "divide by zero" exception from above. For now, I fixed it the easiest and most obvious way: Check if the result is sane and if it isn't use a sane default instead. I went for "100" in the latter case, simply because /sys/devices/platform/lis3lv02d/rate returns it on a successful boot. Signed-off-by: Christian Lamparter Signed-off-by: Éric Piel Cc: Matthew Garrett Cc: Witold Pilat Cc: Lyall Pearce Cc: Malte Starostik Cc: Ilkka Koskinen Cc: Thadeu Lima de Souza Cascardo Cc: Christian Lamparter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/platform/x86/hp_accel.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/platform/x86/hp_accel.c') diff --git a/drivers/platform/x86/hp_accel.c b/drivers/platform/x86/hp_accel.c index 1b52d00e2f9..891e71f75f5 100644 --- a/drivers/platform/x86/hp_accel.c +++ b/drivers/platform/x86/hp_accel.c @@ -354,8 +354,7 @@ static int lis3lv02d_suspend(struct acpi_device *device, pm_message_t state) static int lis3lv02d_resume(struct acpi_device *device) { - lis3lv02d_poweron(&lis3_dev); - return 0; + return lis3lv02d_poweron(&lis3_dev); } #else #define lis3lv02d_suspend NULL -- cgit v1.2.3-70-g09d2