diff options
| author | Nikolay Aleksandrov <nikolay@redhat.com> | 2013-10-24 12:09:24 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-10-26 01:26:58 +0200 |
| commit | c7c6effdeffcafd792b9f880ad52e48689eea4ad (patch) | |
| tree | b80c4d38acd41a1d7b3afcbc5ba5a2f1958d401e /drivers/net/netconsole.c | |
| parent | netconsole: fix NULL pointer dereference (diff) | |
| download | linux-c7c6effdeffcafd792b9f880ad52e48689eea4ad.tar.xz linux-c7c6effdeffcafd792b9f880ad52e48689eea4ad.zip | |
netconsole: fix multiple race conditions
In every netconsole option that can be set through configfs there's a
race when checking for nt->enabled since it can be modified at the same
time. Probably the most damage can be done by store_enabled when racing
with another instance of itself. Fix all the races with one stone by
moving the mutex lock around the ->store call for all options.
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/netconsole.c')
| -rw-r--r-- | drivers/net/netconsole.c | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 1505dcb950fa..c9a15925a1f7 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -325,9 +325,7 @@ static ssize_t store_enabled(struct netconsole_target *nt, return -EINVAL; } - mutex_lock(&nt->mutex); if (enabled) { /* 1 */ - /* * Skip netpoll_parse_options() -- all the attributes are * already configured via configfs. Just print them out. @@ -335,13 +333,10 @@ static ssize_t store_enabled(struct netconsole_target *nt, netpoll_print_options(&nt->np); err = netpoll_setup(&nt->np); - if (err) { - mutex_unlock(&nt->mutex); + if (err) return err; - } printk(KERN_INFO "netconsole: network logging started\n"); - } else { /* 0 */ /* We need to disable the netconsole before cleaning it up * otherwise we might end up in write_msg() with @@ -354,7 +349,6 @@ static ssize_t store_enabled(struct netconsole_target *nt, } nt->enabled = enabled; - mutex_unlock(&nt->mutex); return strnlen(buf, count); } @@ -571,8 +565,10 @@ static ssize_t netconsole_target_attr_store(struct config_item *item, struct netconsole_target_attr *na = container_of(attr, struct netconsole_target_attr, attr); + mutex_lock(&nt->mutex); if (na->store) ret = na->store(nt, buf, count); + mutex_unlock(&nt->mutex); return ret; } |