2006-09-02 08:11:32

by Miles Lane

[permalink] [raw]
Subject: 2.6.18-rc5-mm1 -- possible circular locking dependency detected

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.18-rc5-mm1 #6
-------------------------------------------------------
wpa_supplicant/4658 is trying to acquire lock:
(crypto_alg_sem){----}, at: [__crypto_lookup_template+20/168]
__crypto_lookup_template+0x14/0xa8

but task is already holding lock:
((crypto_chain).rwsem){----}, at:
[blocking_notifier_call_chain+14/45]
blocking_notifier_call_chain+0xe/0x2d

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 ((crypto_chain).rwsem){----}:
[add_lock_to_list+95/125] add_lock_to_list+0x5f/0x7d
[__lock_acquire+2327/2552] __lock_acquire+0x917/0x9f8
[lock_acquire+86/116] lock_acquire+0x56/0x74
[down_read+39/57] down_read+0x27/0x39
[blocking_notifier_call_chain+14/45]
blocking_notifier_call_chain+0xe/0x2d
[crypto_register_template+79/99] crypto_register_template+0x4f/0x63
[hmac_module_init+13/15] hmac_module_init+0xd/0xf
[init+141/531] init+0x8d/0x213
[kernel_thread_helper+7/16] kernel_thread_helper+0x7/0x10
[save_stack_trace+25/51] save_stack_trace+0x19/0x33
[save_trace+63/200] save_trace+0x3f/0xc8
[add_lock_to_list+95/125] add_lock_to_list+0x5f/0x7d
[__lock_acquire+2327/2552] __lock_acquire+0x917/0x9f8
[lock_acquire+86/116] lock_acquire+0x56/0x74
[down_read+39/57] down_read+0x27/0x39
[blocking_notifier_call_chain+14/45]
blocking_notifier_call_chain+0xe/0x2d
[crypto_register_template+79/99] crypto_register_template+0x4f/0x63
[hmac_module_init+13/15] hmac_module_init+0xd/0xf
[init+141/531] init+0x8d/0x213
[kernel_thread_helper+7/16] kernel_thread_helper+0x7/0x10
[<ffffffff>] 0xffffffff

-> #0 (crypto_alg_sem){----}:
[print_circular_bug_tail+48/100] print_circular_bug_tail+0x30/0x64
[__lock_acquire+2126/2552] __lock_acquire+0x84e/0x9f8
[lock_acquire+86/116] lock_acquire+0x56/0x74
[down_read+39/57] down_read+0x27/0x39
[__crypto_lookup_template+20/168] __crypto_lookup_template+0x14/0xa8
[crypto_lookup_template+14/37] crypto_lookup_template+0xe/0x25
[pg0+927817926/1051247616] cryptomgr_notify+0xc6/0x1e0 [cryptomgr]
[notifier_call_chain+24/50] notifier_call_chain+0x18/0x32
[blocking_notifier_call_chain+28/45]
blocking_notifier_call_chain+0x1c/0x2d
[crypto_alg_mod_lookup+347/481] crypto_alg_mod_lookup+0x15b/0x1e1
[crypto_alloc_base+21/96] crypto_alloc_base+0x15/0x60
[prism2_wep_init+50/107] prism2_wep_init+0x32/0x6b
[ieee80211_wx_set_encodeext+733/1345]
ieee80211_wx_set_encodeext+0x2dd/0x541
[pg0+928579102/1051247616] bcm43xx_wx_set_encodingext+0x1f/0x21 [bcm43xx]
[ioctl_standard_call+365/563] ioctl_standard_call+0x16d/0x233
[wireless_process_ioctl+87/799] wireless_process_ioctl+0x57/0x31f
[dev_ioctl+1072/1137] dev_ioctl+0x430/0x471
[sock_ioctl+437/458] sock_ioctl+0x1b5/0x1ca
[do_ioctl+36/102] do_ioctl+0x24/0x66
[vfs_ioctl+600/619] vfs_ioctl+0x258/0x26b
[sys_ioctl+70/99] sys_ioctl+0x46/0x63
[sysenter_past_esp+86/141] sysenter_past_esp+0x56/0x8d
[save_stack_trace+25/51] save_stack_trace+0x19/0x33
[save_trace+63/200] save_trace+0x3f/0xc8
[print_circular_bug_tail+48/100] print_circular_bug_tail+0x30/0x64
[__lock_acquire+2126/2552] __lock_acquire+0x84e/0x9f8
[lock_acquire+86/116] lock_acquire+0x56/0x74
[down_read+39/57] down_read+0x27/0x39
[__crypto_lookup_template+20/168] __crypto_lookup_template+0x14/0xa8
[crypto_lookup_template+14/37] crypto_lookup_template+0xe/0x25
[pg0+927817926/1051247616] cryptomgr_notify+0xc6/0x1e0 [cryptomgr]
[notifier_call_chain+24/50] notifier_call_chain+0x18/0x32
[blocking_notifier_call_chain+28/45]
blocking_notifier_call_chain+0x1c/0x2d
[crypto_alg_mod_lookup+347/481] crypto_alg_mod_lookup+0x15b/0x1e1
[crypto_alloc_base+21/96] crypto_alloc_base+0x15/0x60
[prism2_wep_init+50/107] prism2_wep_init+0x32/0x6b
[ieee80211_wx_set_encodeext+733/1345]
ieee80211_wx_set_encodeext+0x2dd/0x541
[pg0+928579102/1051247616] bcm43xx_wx_set_encodingext+0x1f/0x21 [bcm43xx]
[ioctl_standard_call+365/563] ioctl_standard_call+0x16d/0x233
[wireless_process_ioctl+87/799] wireless_process_ioctl+0x57/0x31f
[dev_ioctl+1072/1137] dev_ioctl+0x430/0x471
[sock_ioctl+437/458] sock_ioctl+0x1b5/0x1ca
[do_ioctl+36/102] do_ioctl+0x24/0x66
[vfs_ioctl+600/619] vfs_ioctl+0x258/0x26b
[sys_ioctl+70/99] sys_ioctl+0x46/0x63
[sysenter_past_esp+86/141] sysenter_past_esp+0x56/0x8d
[<ffffffff>] 0xffffffff

other info that might help us debug this:

2 locks held by wpa_supplicant/4658:
#0: (rtnl_mutex){--..}, at: [mutex_lock+25/32] mutex_lock+0x19/0x20
#1: ((crypto_chain).rwsem){----}, at:
[blocking_notifier_call_chain+14/45]
blocking_notifier_call_chain+0xe/0x2d

stack backtrace:
[dump_trace+105/439] dump_trace+0x69/0x1b7
[show_trace_log_lvl+21/40] show_trace_log_lvl+0x15/0x28
[show_trace+22/25] show_trace+0x16/0x19
[dump_stack+24/29] dump_stack+0x18/0x1d
[print_circular_bug_tail+89/100] print_circular_bug_tail+0x59/0x64
[__lock_acquire+2126/2552] __lock_acquire+0x84e/0x9f8
[lock_acquire+86/116] lock_acquire+0x56/0x74
[down_read+39/57] down_read+0x27/0x39
[__crypto_lookup_template+20/168] __crypto_lookup_template+0x14/0xa8
[crypto_lookup_template+14/37] crypto_lookup_template+0xe/0x25
[pg0+927817926/1051247616] cryptomgr_notify+0xc6/0x1e0 [cryptomgr]
[notifier_call_chain+24/50] notifier_call_chain+0x18/0x32
[blocking_notifier_call_chain+28/45] blocking_notifier_call_chain+0x1c/0x2d
[crypto_alg_mod_lookup+347/481] crypto_alg_mod_lookup+0x15b/0x1e1
[crypto_alloc_base+21/96] crypto_alloc_base+0x15/0x60
[prism2_wep_init+50/107] prism2_wep_init+0x32/0x6b
[ieee80211_wx_set_encodeext+733/1345] ieee80211_wx_set_encodeext+0x2dd/0x541
[pg0+928579102/1051247616] bcm43xx_wx_set_encodingext+0x1f/0x21 [bcm43xx]
[ioctl_standard_call+365/563] ioctl_standard_call+0x16d/0x233
[wireless_process_ioctl+87/799] wireless_process_ioctl+0x57/0x31f
[dev_ioctl+1072/1137] dev_ioctl+0x430/0x471
[sock_ioctl+437/458] sock_ioctl+0x1b5/0x1ca
[do_ioctl+36/102] do_ioctl+0x24/0x66
[vfs_ioctl+600/619] vfs_ioctl+0x258/0x26b
[sys_ioctl+70/99] sys_ioctl+0x46/0x63
[sysenter_past_esp+86/141] sysenter_past_esp+0x56/0x8d
DWARF2 unwinder stuck at sysenter_past_esp+0x56/0x8d

Leftover inexact backtrace:

[show_trace_log_lvl+21/40] show_trace_log_lvl+0x15/0x28
[show_trace+22/25] show_trace+0x16/0x19
[dump_stack+24/29] dump_stack+0x18/0x1d
[print_circular_bug_tail+89/100] print_circular_bug_tail+0x59/0x64
[__lock_acquire+2126/2552] __lock_acquire+0x84e/0x9f8
[lock_acquire+86/116] lock_acquire+0x56/0x74
[down_read+39/57] down_read+0x27/0x39
[__crypto_lookup_template+20/168] __crypto_lookup_template+0x14/0xa8
[crypto_lookup_template+14/37] crypto_lookup_template+0xe/0x25
[pg0+927817926/1051247616] cryptomgr_notify+0xc6/0x1e0 [cryptomgr]
[notifier_call_chain+24/50] notifier_call_chain+0x18/0x32
[blocking_notifier_call_chain+28/45] blocking_notifier_call_chain+0x1c/0x2d
[crypto_alg_mod_lookup+347/481] crypto_alg_mod_lookup+0x15b/0x1e1
[crypto_alloc_base+21/96] crypto_alloc_base+0x15/0x60
[prism2_wep_init+50/107] prism2_wep_init+0x32/0x6b
[ieee80211_wx_set_encodeext+733/1345] ieee80211_wx_set_encodeext+0x2dd/0x541
[pg0+928579102/1051247616] bcm43xx_wx_set_encodingext+0x1f/0x21 [bcm43xx]
[ioctl_standard_call+365/563] ioctl_standard_call+0x16d/0x233
[wireless_process_ioctl+87/799] wireless_process_ioctl+0x57/0x31f
[dev_ioctl+1072/1137] dev_ioctl+0x430/0x471
[sock_ioctl+437/458] sock_ioctl+0x1b5/0x1ca
[do_ioctl+36/102] do_ioctl+0x24/0x66
[vfs_ioctl+600/619] vfs_ioctl+0x258/0x26b
[sys_ioctl+70/99] sys_ioctl+0x46/0x63
[sysenter_past_esp+86/141] sysenter_past_esp+0x56/0x8d
=======================

--
VGER BF report: H 2.60902e-15


2006-09-02 10:29:24

by Herbert Xu

[permalink] [raw]
Subject: Re: 2.6.18-rc5-mm1 -- possible circular locking dependency detected

On Sat, Sep 02, 2006 at 01:11:30AM -0700, Miles Lane wrote:
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.18-rc5-mm1 #6
> -------------------------------------------------------
> wpa_supplicant/4658 is trying to acquire lock:
> (crypto_alg_sem){----}, at: [__crypto_lookup_template+20/168]
> __crypto_lookup_template+0x14/0xa8
>
> but task is already holding lock:
> ((crypto_chain).rwsem){----}, at:
> [blocking_notifier_call_chain+14/45]
> blocking_notifier_call_chain+0xe/0x2d

Thanks for the report. I started with the right code but then optimised
it away :) I've checked in this changeset.

[CRYPTO] cryptomgr: Defer probing into a work queue

We cannot perform the probing directly as we're holding at least one
lock that may be retaken during probing. So this patch be defers it
to a work queue.

Signed-off-by: Herbert Xu <[email protected]>

Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
diff --git a/crypto/cryptomgr.c b/crypto/cryptomgr.c
index ebe637c..9b5b156 100644
--- a/crypto/cryptomgr.c
+++ b/crypto/cryptomgr.c
@@ -19,35 +19,81 @@ #include <linux/notifier.h>
#include <linux/rtnetlink.h>
#include <linux/sched.h>
#include <linux/string.h>
+#include <linux/workqueue.h>

#include "internal.h"

struct cryptomgr_param {
+ struct work_struct work;
+
struct {
struct rtattr attr;
struct crypto_attr_alg data;
} alg;
+
+ struct {
+ u32 type;
+ u32 mask;
+ char name[CRYPTO_MAX_ALG_NAME];
+ } larval;
+
+ char template[CRYPTO_MAX_ALG_NAME];
};

-static int cryptomgr_probe(struct crypto_larval *larval)
+static void cryptomgr_probe(void *data)
{
- struct cryptomgr_param param;
+ struct cryptomgr_param *param = data;
struct crypto_template *tmpl;
struct crypto_instance *inst;
+ int err;
+
+ tmpl = crypto_lookup_template(param->template);
+ if (!tmpl)
+ goto err;
+
+ do {
+ inst = tmpl->alloc(&param->alg, sizeof(param->alg));
+ if (IS_ERR(inst))
+ err = PTR_ERR(inst);
+ else if ((err = crypto_register_instance(tmpl, inst)))
+ tmpl->free(inst);
+ } while (err == -EAGAIN && !signal_pending(current));
+
+ crypto_tmpl_put(tmpl);
+
+ if (err)
+ goto err;
+
+out:
+ kfree(param);
+ return;
+
+err:
+ crypto_larval_error(param->larval.name, param->larval.type,
+ param->larval.mask);
+ goto out;
+}
+
+static int cryptomgr_schedule_probe(struct crypto_larval *larval)
+{
+ struct cryptomgr_param *param;
const char *name = larval->alg.cra_name;
const char *p;
unsigned int len;
- int err;
+
+ param = kmalloc(sizeof(*param), GFP_KERNEL);
+ if (!param)
+ goto err;

for (p = name; isalnum(*p) || *p == '-' || *p == '_'; p++)
;

len = p - name;
if (!len || *p != '(')
- return NOTIFY_OK;
+ goto err_free_param;

- memcpy(param.alg.data.name, name, len);
- param.alg.data.name[len] = 0;
+ memcpy(param->template, name, len);
+ param->template[len] = 0;

name = p + 1;
for (p = name; isalnum(*p) || *p == '-' || *p == '_'; p++)
@@ -55,36 +101,26 @@ static int cryptomgr_probe(struct crypto

len = p - name;
if (!len || *p != ')' || p[1])
- return NOTIFY_OK;
+ goto err_free_param;

- tmpl = crypto_lookup_template(param.alg.data.name);
- if (!tmpl)
- goto err;
+ param->alg.attr.rta_len = sizeof(param->alg);
+ param->alg.attr.rta_type = CRYPTOA_ALG;
+ memcpy(param->alg.data.name, name, len);
+ param->alg.data.name[len] = 0;

- param.alg.attr.rta_len = sizeof(param.alg);
- param.alg.attr.rta_type = CRYPTOA_ALG;
- memcpy(param.alg.data.name, name, len);
- param.alg.data.name[len] = 0;
+ memcpy(param->larval.name, larval->alg.cra_name, CRYPTO_MAX_ALG_NAME);
+ param->larval.type = larval->alg.cra_flags;
+ param->larval.mask = larval->mask;

- do {
- inst = tmpl->alloc(&param, sizeof(param));
- if (IS_ERR(inst))
- err = PTR_ERR(inst);
- else if ((err = crypto_register_instance(tmpl, inst)))
- tmpl->free(inst);
- } while (err == -EAGAIN && !signal_pending(current));
-
- crypto_tmpl_put(tmpl);
-
- if (err)
- goto err;
+ INIT_WORK(&param->work, cryptomgr_probe, param);
+ schedule_work(&param->work);

return NOTIFY_STOP;

+err_free_param:
+ kfree(param);
err:
- crypto_larval_error(larval->alg.cra_name, larval->alg.cra_flags,
- larval->mask);
- return NOTIFY_STOP;
+ return NOTIFY_OK;
}

static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
@@ -92,7 +128,7 @@ static int cryptomgr_notify(struct notif
{
switch (msg) {
case CRYPTO_MSG_ALG_REQUEST:
- return cryptomgr_probe(data);
+ return cryptomgr_schedule_probe(data);
}

return NOTIFY_DONE;