diff options
author | Éric Piel <eric.piel@tremplin-utc.net> | 2011-10-31 17:10:31 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-10-31 17:30:51 -0700 |
commit | 1510dd5954be5070e46b155eb32362dc73d9e9cb (patch) | |
tree | 75d9a020f23c015739e3c17d742482b0866024b0 /drivers/misc | |
parent | 65807044760e03ebf766973c5e94a2ea1d57937b (diff) |
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>
Diffstat (limited to 'drivers/misc')
-rw-r--r-- | drivers/misc/lis3lv02d/lis3lv02d.c | 36 | ||||
-rw-r--r-- | drivers/misc/lis3lv02d/lis3lv02d.h | 2 |
2 files changed, 31 insertions, 7 deletions
diff --git a/drivers/misc/lis3lv02d/lis3lv02d.c b/drivers/misc/lis3lv02d/lis3lv02d.c index 8b51cd62d06..1fc67156656 100644 --- a/drivers/misc/lis3lv02d/lis3lv02d.c +++ b/drivers/misc/lis3lv02d/lis3lv02d.c @@ -206,6 +206,18 @@ static int lis3lv02d_get_odr(void) return lis3_dev.odrs[(ctrl >> shift)]; } +static int lis3lv02d_get_pwron_wait(struct lis3lv02d *lis3) +{ + int div = lis3lv02d_get_odr(); + + if (WARN_ONCE(div == 0, "device returned spurious data")) + return -ENXIO; + + /* LIS3 power on delay is quite long */ + msleep(lis3->pwron_delay / div); + return 0; +} + static int lis3lv02d_set_odr(int rate) { u8 ctrl; @@ -266,7 +278,9 @@ static int lis3lv02d_selftest(struct lis3lv02d *lis3, s16 results[3]) lis3->read(lis3, ctlreg, ®); lis3->write(lis3, ctlreg, (reg | selftest)); - msleep(lis3->pwron_delay / lis3lv02d_get_odr()); + ret = lis3lv02d_get_pwron_wait(lis3); + if (ret) + goto fail; /* Read directly to avoid axis remap */ x = lis3->read_data(lis3, OUTX); @@ -275,7 +289,9 @@ static int lis3lv02d_selftest(struct lis3lv02d *lis3, s16 results[3]) /* back to normal settings */ lis3->write(lis3, ctlreg, reg); - msleep(lis3->pwron_delay / lis3lv02d_get_odr()); + ret = lis3lv02d_get_pwron_wait(lis3); + if (ret) + goto fail; results[0] = x - lis3->read_data(lis3, OUTX); results[1] = y - lis3->read_data(lis3, OUTY); @@ -363,8 +379,9 @@ void lis3lv02d_poweroff(struct lis3lv02d *lis3) } EXPORT_SYMBOL_GPL(lis3lv02d_poweroff); -void lis3lv02d_poweron(struct lis3lv02d *lis3) +int lis3lv02d_poweron(struct lis3lv02d *lis3) { + int err; u8 reg; lis3->init(lis3); @@ -384,11 +401,14 @@ void lis3lv02d_poweron(struct lis3lv02d *lis3) lis3->write(lis3, CTRL_REG2, reg); } - /* LIS3 power on delay is quite long */ - msleep(lis3->pwron_delay / lis3lv02d_get_odr()); + err = lis3lv02d_get_pwron_wait(lis3); + if (err) + return err; if (lis3->reg_ctrl) lis3_context_restore(lis3); + + return 0; } EXPORT_SYMBOL_GPL(lis3lv02d_poweron); @@ -928,7 +948,11 @@ int lis3lv02d_init_device(struct lis3lv02d *dev) atomic_set(&dev->wake_thread, 0); lis3lv02d_add_fs(dev); - lis3lv02d_poweron(dev); + err = lis3lv02d_poweron(dev); + if (err) { + lis3lv02d_remove_fs(dev); + return err; + } if (dev->pm_dev) { pm_runtime_set_active(dev->pm_dev); diff --git a/drivers/misc/lis3lv02d/lis3lv02d.h b/drivers/misc/lis3lv02d/lis3lv02d.h index a1939589eb2..57c64bbcf5f 100644 --- a/drivers/misc/lis3lv02d/lis3lv02d.h +++ b/drivers/misc/lis3lv02d/lis3lv02d.h @@ -285,7 +285,7 @@ int lis3lv02d_init_device(struct lis3lv02d *lis3); int lis3lv02d_joystick_enable(void); void lis3lv02d_joystick_disable(void); void lis3lv02d_poweroff(struct lis3lv02d *lis3); -void lis3lv02d_poweron(struct lis3lv02d *lis3); +int lis3lv02d_poweron(struct lis3lv02d *lis3); int lis3lv02d_remove_fs(struct lis3lv02d *lis3); extern struct lis3lv02d lis3_dev; |