lkml.org 
[lkml]   [2019]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] hwmon: pmbus: protect read-modify-write with lock
On Mon, Jun 03, 2019 at 01:11:45PM +0000, Sverdlin, Alexander (Nokia - DE/Ulm) wrote:
> Hi!
>
> On 30/05/2019 08:45, Adamski, Krzysztof (Nokia - PL/Wroclaw) wrote:
> > The operation done in the pmbus_update_fan() function is a
> > read-modify-write operation but it lacks any kind of lock protection
> > which may cause problems if run more than once simultaneously. This
> > patch uses an existing update_lock mutex to fix this problem.
> >
> > Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
> > ---
> >
> > I'm resending this patch to proper recipients this time. Sorry if the
> > previous submission confused anybody.
> >
> > drivers/hwmon/pmbus/pmbus_core.c | 11 ++++++++---
> > 1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> > index ef7ee90ee785..94adbede7912 100644
> > --- a/drivers/hwmon/pmbus/pmbus_core.c
> > +++ b/drivers/hwmon/pmbus/pmbus_core.c
> > @@ -268,6 +268,7 @@ int pmbus_update_fan(struct i2c_client *client, int page, int id,
> > int rv;
> > u8 to;
> >
> > + mutex_lock(&data->update_lock);
> > from = pmbus_read_byte_data(client, page,
> > pmbus_fan_config_registers[id]);
> > if (from < 0)
> > @@ -278,11 +279,15 @@ int pmbus_update_fan(struct i2c_client *client, int page, int id,
> > rv = pmbus_write_byte_data(client, page,
> > pmbus_fan_config_registers[id], to);
> > if (rv < 0)
> > - return rv;
> > + goto out;
> > }
> >
> > - return _pmbus_write_word_data(client, page,
> > - pmbus_fan_command_registers[id], command);
> > + rv = _pmbus_write_word_data(client, page,
> > + pmbus_fan_command_registers[id], command);
> > +
> > +out:
> > + mutex_lock(&data->update_lock);
>
> This has to be mutex_unlock()...
>

Not only that - it is also recursive.

Guenter

\
 
 \ /
  Last update: 2019-06-03 18:19    [W:0.104 / U:0.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site