[PATCH 3.2 039/221] iscsi-target: Drop problematic active_ts_list usage

From: Ben Hutchings
Date: Mon May 04 2015 - 22:00:01 EST

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3.2.69-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

commit 3fd7b60f2c7418239d586e359e0c6d8503e10646 upstream.

This patch drops legacy active_ts_list usage within iscsi_target_tq.c
code. It was originally used to track the active thread sets during
iscsi-target shutdown, and is no longer used by modern upstream code.

Two people have reported list corruption using traditional iscsi-target
and iser-target with the following backtrace, that appears to be related
to iscsi_thread_set->ts_list being used across both active_ts_list and
inactive_ts_list.

[ 60.782534] ------------[ cut here ]------------
[ 60.782543] WARNING: CPU: 0 PID: 9430 at lib/list_debug.c:53 __list_del_entry+0x63/0xd0()
[ 60.782545] list_del corruption, ffff88045b00d180->next is LIST_POISON1 (dead000000100100)
[ 60.782546] Modules linked in: ib_srpt tcm_qla2xxx qla2xxx tcm_loop tcm_fc libfc scsi_transport_fc scsi_tgt ib_isert rdma_cm iw_cm ib_addr iscsi_target_mod target_core_pscsi target_core_file target_core_iblock target_core_mod configfs ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 ipt_REJECT xt_CHECKSUM iptable_mangle iptable_filter ip_tables bridge stp llc autofs4 sunrpc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6 ib_ipoib ib_cm ib_uverbs ib_umad mlx4_en mlx4_ib ib_sa ib_mad ib_core mlx4_core dm_mirror dm_region_hash dm_log dm_mod vhost_net macvtap macvlan vhost tun kvm_intel kvm uinput iTCO_wdt iTCO_vendor_support microcode serio_raw pcspkr sb_edac edac_core sg i2c_i801 lpc_ich mfd_core mtip32xx igb i2c_algo_bit i2c_core ptp pps_core ioatdma dca wmi ext3(F) jbd(F) mbcache(F) sd_mod(F) crc_t10dif(F) crct10dif_common(F) ahci(F) libahci(F) isci(F) libsas(F) scsi_transport_sas(F) [last unloaded: speedstep_lib]
[ 60.782597] CPU: 0 PID: 9430 Comm: iscsi_ttx Tainted: GF 3.12.19+ #2
[ 60.782598] Hardware name: Supermicro X9DRX+-F/X9DRX+-F, BIOS 3.00 07/09/2013
[ 60.782599] 0000000000000035 ffff88044de31d08 ffffffff81553ae7 0000000000000035
[ 60.782602] ffff88044de31d58 ffff88044de31d48 ffffffff8104d1cc 0000000000000002
[ 60.782605] ffff88045b00d180 ffff88045b00d0c0 ffff88045b00d0c0 ffff88044de31e58
[ 60.782607] Call Trace:
[ 60.782611] [<ffffffff81553ae7>] dump_stack+0x49/0x62
[ 60.782615] [<ffffffff8104d1cc>] warn_slowpath_common+0x8c/0xc0
[ 60.782618] [<ffffffff8104d2b6>] warn_slowpath_fmt+0x46/0x50
[ 60.782620] [<ffffffff81280933>] __list_del_entry+0x63/0xd0
[ 60.782622] [<ffffffff812809b1>] list_del+0x11/0x40
[ 60.782630] [<ffffffffa06e7cf9>] iscsi_del_ts_from_active_list+0x29/0x50 [iscsi_target_mod]
[ 60.782635] [<ffffffffa06e87b1>] iscsi_tx_thread_pre_handler+0xa1/0x180 [iscsi_target_mod]
[ 60.782642] [<ffffffffa06fb9ae>] iscsi_target_tx_thread+0x4e/0x220 [iscsi_target_mod]
[ 60.782647] [<ffffffffa06fb960>] ? iscsit_handle_snack+0x190/0x190 [iscsi_target_mod]
[ 60.782652] [<ffffffffa06fb960>] ? iscsit_handle_snack+0x190/0x190 [iscsi_target_mod]
[ 60.782655] [<ffffffff8106f99e>] kthread+0xce/0xe0
[ 60.782657] [<ffffffff8106f8d0>] ? kthread_freezable_should_stop+0x70/0x70
[ 60.782660] [<ffffffff8156026c>] ret_from_fork+0x7c/0xb0
[ 60.782662] [<ffffffff8106f8d0>] ? kthread_freezable_should_stop+0x70/0x70
[ 60.782663] ---[ end trace 9662f4a661d33965 ]---

Since this code is no longer used, go ahead and drop the problematic usage
all-together.

Reported-by: Gavin Guo <gavin.guo@xxxxxxxxxxxxx>
Reported-by: Moussa Ba <moussaba@xxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
[bwh: Backported to 3.2:
- Adjust context
- Also delete redundant initialisation, deleted upstream in commit
d0f474e50192 ('target: Use LIST_HEAD()/DEFINE_MUTEX() for static objects')]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/target/iscsi/iscsi_target_tq.c | 28 +++++-----------------------
1 file changed, 5 insertions(+), 23 deletions(-)

--- a/drivers/target/iscsi/iscsi_target_tq.c
+++ b/drivers/target/iscsi/iscsi_target_tq.c
@@ -26,36 +26,22 @@
#include "iscsi_target_tq.h"
#include "iscsi_target.h"

-static LIST_HEAD(active_ts_list);
static LIST_HEAD(inactive_ts_list);
-static DEFINE_SPINLOCK(active_ts_lock);
static DEFINE_SPINLOCK(inactive_ts_lock);
static DEFINE_SPINLOCK(ts_bitmap_lock);

-static void iscsi_add_ts_to_active_list(struct iscsi_thread_set *ts)
-{
- spin_lock(&active_ts_lock);
- list_add_tail(&ts->ts_list, &active_ts_list);
- iscsit_global->active_ts++;
- spin_unlock(&active_ts_lock);
-}
-
extern void iscsi_add_ts_to_inactive_list(struct iscsi_thread_set *ts)
{
+ if (!list_empty(&ts->ts_list)) {
+ WARN_ON(1);
+ return;
+ }
spin_lock(&inactive_ts_lock);
list_add_tail(&ts->ts_list, &inactive_ts_list);
iscsit_global->inactive_ts++;
spin_unlock(&inactive_ts_lock);
}

-static void iscsi_del_ts_from_active_list(struct iscsi_thread_set *ts)
-{
- spin_lock(&active_ts_lock);
- list_del(&ts->ts_list);
- iscsit_global->active_ts--;
- spin_unlock(&active_ts_lock);
-}
-
static struct iscsi_thread_set *iscsi_get_ts_from_inactive_list(void)
{
struct iscsi_thread_set *ts;
@@ -69,7 +55,7 @@ static struct iscsi_thread_set *iscsi_ge
list_for_each_entry(ts, &inactive_ts_list, ts_list)
break;

- list_del(&ts->ts_list);
+ list_del_init(&ts->ts_list);
iscsit_global->inactive_ts--;
spin_unlock(&inactive_ts_lock);

@@ -220,8 +206,6 @@ static void iscsi_deallocate_extra_threa

void iscsi_activate_thread_set(struct iscsi_conn *conn, struct iscsi_thread_set *ts)
{
- iscsi_add_ts_to_active_list(ts);
-
spin_lock_bh(&ts->ts_state_lock);
conn->thread_set = ts;
ts->conn = conn;
@@ -424,7 +408,6 @@ struct iscsi_conn *iscsi_rx_thread_pre_h

if (ts->delay_inactive && (--ts->thread_count == 0)) {
spin_unlock_bh(&ts->ts_state_lock);
- iscsi_del_ts_from_active_list(ts);

if (!iscsit_global->in_shutdown)
iscsi_deallocate_extra_thread_sets();
@@ -477,7 +460,6 @@ struct iscsi_conn *iscsi_tx_thread_pre_h

if (ts->delay_inactive && (--ts->thread_count == 0)) {
spin_unlock_bh(&ts->ts_state_lock);
- iscsi_del_ts_from_active_list(ts);

if (!iscsit_global->in_shutdown)
iscsi_deallocate_extra_thread_sets();
@@ -536,10 +518,8 @@ int iscsi_thread_set_init(void)
return -ENOMEM;
}

- spin_lock_init(&active_ts_lock);
spin_lock_init(&inactive_ts_lock);
spin_lock_init(&ts_bitmap_lock);
- INIT_LIST_HEAD(&active_ts_list);
INIT_LIST_HEAD(&inactive_ts_list);

return 0;

--
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Next message: Ben Hutchings: "[PATCH 3.2 079/221] drm/radeon: do a posting read in rs600_set_irq"
Previous message: Ben Hutchings: "[PATCH 3.2 030/221] ALSA: off by one bug in snd_riptide_joystick_probe()"
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