Éric Piel 1510dd5954 lis3lv02d: avoid divide by zero due to unchecked ... 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:[<ffffffffa014b427>] [<ffffffffa014b427>] 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: [<ffffffffa014bcc1>] lis3lv02d_init_device+0x1ce/0x496 [lis3lv02d] [<ffffffffa01522ff>] lis3lv02d_add+0x10f/0x17c [hp_accel] [<ffffffff81233e11>] 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 <f7> f9 89 c7 e8 93 82 ef e0 48 83 7b 30 00 74 2d 45 31 e4 80 7b=20 RIP [<ffffffffa014b427>] lis3lv02d_poweron+0x4e/0x94 [lis3lv02d] RSP <ffff8801d6407cf8> >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 <chunkeey@googlemail.com> Signed-off-by: Éric Piel <eric.piel@tremplin-utc.net> Cc: Matthew Garrett <mjg@redhat.com> Cc: Witold Pilat <witold.pilat@gmail.com> Cc: Lyall Pearce <lyall.pearce@hp.com> Cc: Malte Starostik <m-starostik@versanet.de> Cc: Ilkka Koskinen <ilkka.koskinen@nokia.com> Cc: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com> Cc: Christian Lamparter <chunkeey@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2011-10-31 17:30:51 -07:00
..
x86	lis3lv02d: avoid divide by zero due to unchecked	2011-10-31 17:30:51 -07:00
Kconfig	Kconfig: Remove useless and sometimes wrong comments	2009-11-09 09:40:56 +01:00
Makefile	create drivers/platform/x86/ from drivers/misc/	2008-12-19 04:42:32 -05:00