netfilter: nf_log: fix sleeping function called from invalid context in seq_show()
[ 171.925285] BUG: sleeping function called from invalid context at kernel/mutex.c:280
[ 171.925296] in_atomic(): 1, irqs_disabled(): 0, pid: 671, name: grep
[ 171.925306] 2 locks held by grep/671:
[ 171.925312] #0: (&p->lock){+.+.+.}, at: [<c10b8acd>] seq_read+0x25/0x36c
[ 171.925340] #1: (rcu_read_lock){.+.+..}, at: [<c1391dac>] seq_start+0x0/0x44
[ 171.925372] Pid: 671, comm: grep Not tainted 2.6.31.6-4-netbook #3
[ 171.925380] Call Trace:
[ 171.925398] [<c105104e>] ? __debug_show_held_locks+0x1e/0x20
[ 171.925414] [<c10264ac>] __might_sleep+0xfb/0x102
[ 171.925430] [<c1461521>] mutex_lock_nested+0x1c/0x2ad
[ 171.925444] [<c1391c9e>] seq_show+0x74/0x127
[ 171.925456] [<c10b8c5c>] seq_read+0x1b4/0x36c
[ 171.925469] [<c10b8aa8>] ? seq_read+0x0/0x36c
[ 171.925483] [<c10d5c8e>] proc_reg_read+0x60/0x74
[ 171.925496] [<c10d5c2e>] ? proc_reg_read+0x0/0x74
[ 171.925510] [<c10a4468>] vfs_read+0x87/0x110
[ 171.925523] [<c10a458a>] sys_read+0x3b/0x60
[ 171.925538] [<c1002a49>] syscall_call+0x7/0xb
Fix it by replacing RCU with nf_log_mutex.
Reported-by: "Yin, Kangkai" <kangkai.yin@intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
index c93494f..d65d348 100644
--- a/net/netfilter/nf_log.c
+++ b/net/netfilter/nf_log.c
@@ -128,9 +128,8 @@
#ifdef CONFIG_PROC_FS
static void *seq_start(struct seq_file *seq, loff_t *pos)
- __acquires(RCU)
{
- rcu_read_lock();
+ mutex_lock(&nf_log_mutex);
if (*pos >= ARRAY_SIZE(nf_loggers))
return NULL;
@@ -149,9 +148,8 @@
}
static void seq_stop(struct seq_file *s, void *v)
- __releases(RCU)
{
- rcu_read_unlock();
+ mutex_unlock(&nf_log_mutex);
}
static int seq_show(struct seq_file *s, void *v)
@@ -161,7 +159,7 @@
struct nf_logger *t;
int ret;
- logger = rcu_dereference(nf_loggers[*pos]);
+ logger = nf_loggers[*pos];
if (!logger)
ret = seq_printf(s, "%2lld NONE (", *pos);
@@ -171,22 +169,16 @@
if (ret < 0)
return ret;
- mutex_lock(&nf_log_mutex);
list_for_each_entry(t, &nf_loggers_l[*pos], list[*pos]) {
ret = seq_printf(s, "%s", t->name);
- if (ret < 0) {
- mutex_unlock(&nf_log_mutex);
+ if (ret < 0)
return ret;
- }
if (&t->list[*pos] != nf_loggers_l[*pos].prev) {
ret = seq_printf(s, ",");
- if (ret < 0) {
- mutex_unlock(&nf_log_mutex);
+ if (ret < 0)
return ret;
- }
}
}
- mutex_unlock(&nf_log_mutex);
return seq_printf(s, ")\n");
}
