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authorJason Baron <jbaron@akamai.com>2020-08-21 12:20:14 -0400
committerGuenter Roeck <linux@roeck-us.net>2020-08-21 11:26:35 -0700
commit8aebbbb2d573d0b4afc08b90ac7d73dba2d9da97 (patch)
tree6a649d5c629e1a36d5799106278fe4300ea87d41 /drivers/hwmon
parent51fb91ed5a6fa855a74731610cd5435d83d6e17f (diff)
hwmon: (nct7904) Correct divide by 0
We hit a kernel panic due to a divide by 0 in nct7904_read_fan() for the hwmon_fan_min case. Extend the check to hwmon_fan_input case as well for safety. [ 1656.545650] divide error: 0000 [#1] SMP PTI [ 1656.545779] CPU: 12 PID: 18010 Comm: sensors Not tainted 5.4.47 #1 [ 1656.546065] RIP: 0010:nct7904_read+0x1e9/0x510 [nct7904] ... [ 1656.546549] RAX: 0000000000149970 RBX: ffffbd6b86bcbe08 RCX: 0000000000000000 ... [ 1656.547548] Call Trace: [ 1656.547665] hwmon_attr_show+0x32/0xd0 [hwmon] [ 1656.547783] dev_attr_show+0x18/0x50 [ 1656.547898] sysfs_kf_seq_show+0x99/0x120 [ 1656.548013] seq_read+0xd8/0x3e0 [ 1656.548127] vfs_read+0x89/0x130 [ 1656.548234] ksys_read+0x7d/0xb0 [ 1656.548342] do_syscall_64+0x48/0x110 [ 1656.548451] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: d65a5102a99f5 ("hwmon: (nct7904) Convert to use new hwmon registration API") Signed-off-by: Jason Baron <jbaron@akamai.com> Link: https://lore.kernel.org/r/1598026814-2604-1-git-send-email-jbaron@akamai.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/nct7904.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/hwmon/nct7904.c b/drivers/hwmon/nct7904.c
index b0425694f702..242ff8bee78d 100644
--- a/drivers/hwmon/nct7904.c
+++ b/drivers/hwmon/nct7904.c
@@ -231,7 +231,7 @@ static int nct7904_read_fan(struct device *dev, u32 attr, int channel,
if (ret < 0)
return ret;
cnt = ((ret & 0xff00) >> 3) | (ret & 0x1f);
- if (cnt == 0x1fff)
+ if (cnt == 0 || cnt == 0x1fff)
rpm = 0;
else
rpm = 1350000 / cnt;
@@ -243,7 +243,7 @@ static int nct7904_read_fan(struct device *dev, u32 attr, int channel,
if (ret < 0)
return ret;
cnt = ((ret & 0xff00) >> 3) | (ret & 0x1f);
- if (cnt == 0x1fff)
+ if (cnt == 0 || cnt == 0x1fff)
rpm = 0;
else
rpm = 1350000 / cnt;