If multiple tasks attempt to read the stats, it may happen
that the start_req_done completion is re-initialized while
still being used by another task, causing a list corruption.
This patch fixes the bug by adding a mutex to serialize the
calls to bnx2fc_get_host_stats().
WARNING: at lib/list_debug.c:48 list_del+0x6e/0xa0() (Not tainted)
Hardware name: PowerEdge R820
list_del corruption. prev->next should be 882035627d90, but was
884069541588
Pid: 40267, comm: perl Not tainted 2.6.32-642.3.1.el6.x86_64 #1
Call Trace:
[] ? warn_slowpath_common+0x91/0xe0
[] ? warn_slowpath_fmt+0x46/0x60
[] ? list_del+0x6e/0xa0
[] ? wait_for_common+0x14d/0x180
[] ? default_wake_function+0x0/0x20
[] ? wait_for_completion_timeout+0x13/0x20
[] ? bnx2fc_get_host_stats+0xa1/0x280 [bnx2fc]
[] ? fc_stat_show+0x90/0xc0 [scsi_transport_fc]
[] ? show_fcstat_tx_frames+0x16/0x20 [scsi_transport_fc]
[] ? dev_attr_show+0x27/0x50
[] ? __get_free_pages+0xe/0x50
[] ? sysfs_read_file+0x111/0x200
[] ? vfs_read+0xb5/0x1a0
[] ? fget_light_pos+0x16/0x50
[] ? sys_read+0x51/0xb0
[] ? __audit_syscall_exit+0x25e/0x290
[] ? system_call_fastpath+0x16/0x1b
Signed-off-by: Maurizio Lombardi
---
drivers/scsi/bnx2fc/bnx2fc.h | 1 +
drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 10 --
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/bnx2fc/bnx2fc.h b/drivers/scsi/bnx2fc/bnx2fc.h
index 4fc8ed5..1f424e4 100644
--- a/drivers/scsi/bnx2fc/bnx2fc.h
+++ b/drivers/scsi/bnx2fc/bnx2fc.h
@@ -191,6 +191,7 @@ struct bnx2fc_hba {
struct bnx2fc_cmd_mgr *cmd_mgr;
spinlock_t hba_lock;
struct mutex hba_mutex;
+ struct mutex hba_stats_mutex;
unsigned long adapter_state;
#define ADAPTER_STATE_UP0
#define ADAPTER_STATE_GOING_DOWN1
diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index 93b5a00..902722d 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -663,15 +663,17 @@ static struct fc_host_statistics
*bnx2fc_get_host_stats(struct Scsi_Host *shost)
if (!fw_stats)
return NULL;
+ mutex_lock(&hba->hba_stats_mutex);
+
bnx2fc_stats = fc_get_host_stats(shost);
init_completion(&hba->stat_req_done);
if (bnx2fc_send_stat_req(hba))
- return bnx2fc_stats;
+ goto unlock_stats_mutex;
rc = wait_for_completion_timeout(&hba->stat_req_done, (2 * HZ));
if (!rc) {
BNX2FC_HBA_DBG(lport, "FW stat req timed out\n");
- return bnx2fc_stats;
+ goto unlock_stats_mutex;
}
BNX2FC_STATS(hba, rx_stat2, fc_crc_cnt);
bnx2fc_stats->invalid_crc_count += hba->bfw_stats.fc_crc_cnt;
@@ -693,6 +695,9 @@ static struct fc_host_statistics
*bnx2fc_get_host_stats(struct Scsi_Host *shost)
memcpy(&hba->prev_stats, hba->stats_buffer,
sizeof(struct fcoe_statistics_params));
+
+unlock_stats_mutex:
+ mutex_unlock(&hba->hba_stats_mutex);
return bnx2fc_stats;
}
@@ -1340,6 +1345,7 @@ static struct bnx2fc_hba *bnx2fc_hba_create(struct
cnic_dev *cnic)
}
spin_lock_init(&hba->hba_lock);
mutex_init(&hba->hba_mutex);
+ mutex_init(&hba->hba_stats_mutex);
hba->cnic = cnic;
--
Maurizio Lombardi
