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netfilter: nf_log: fix sleeping function called from invalid context in seq_show()

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[  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>
This commit is contained in:
Wu Fengguang 2009-11-13 09:34:44 +01:00 committed by Patrick McHardy
parent 1c622ae67b
commit 7378396cd1
1 changed files with 5 additions and 13 deletions
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18
net/netfilter/nf_log.c
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@ -128,9 +128,8 @@ EXPORT_SYMBOL(nf_log_packet);
#ifdef CONFIG_PROC_FS #ifdef CONFIG_PROC_FS
static void *seq_start(struct seq_file *seq, loff_t *pos) 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)) if (*pos >= ARRAY_SIZE(nf_loggers))
return NULL; return NULL;
@ -149,9 +148,8 @@ static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
} }
static void seq_stop(struct seq_file *s, void *v) 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) static int seq_show(struct seq_file *s, void *v)
@ -161,7 +159,7 @@ static int seq_show(struct seq_file *s, void *v)
struct nf_logger *t; struct nf_logger *t;
int ret; int ret;
logger = rcu_dereference(nf_loggers[*pos]); logger = nf_loggers[*pos];
if (!logger) if (!logger)
ret = seq_printf(s, "%2lld NONE (", *pos); ret = seq_printf(s, "%2lld NONE (", *pos);
@ -171,22 +169,16 @@ static int seq_show(struct seq_file *s, void *v)
if (ret < 0) if (ret < 0)
return ret; return ret;
mutex_lock(&nf_log_mutex);
list_for_each_entry(t, &nf_loggers_l[*pos], list[*pos]) { list_for_each_entry(t, &nf_loggers_l[*pos], list[*pos]) {
ret = seq_printf(s, "%s", t->name); ret = seq_printf(s, "%s", t->name);
if (ret < 0) { if (ret < 0)
mutex_unlock(&nf_log_mutex);
return ret; return ret;
}
if (&t->list[*pos] != nf_loggers_l[*pos].prev) { if (&t->list[*pos] != nf_loggers_l[*pos].prev) {
ret = seq_printf(s, ","); ret = seq_printf(s, ",");
if (ret < 0) { if (ret < 0)
mutex_unlock(&nf_log_mutex);
return ret; return ret;
} }
} }
}
mutex_unlock(&nf_log_mutex);
return seq_printf(s, ")\n"); return seq_printf(s, ")\n");
} }