From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Maurizio Lombardi , "Martin K . Petersen" , Sasha Levin Subject: [PATCH AUTOSEL for 3.18 043/102] scsi: bnx2fc: fix race condition in bnx2fc_get_host_stats() Date: Mon, 19 Mar 2018 16:12:25 +0000 Message-ID: <20180319161117.17833-43-alexander.levin@microsoft.com> References: <20180319161117.17833-1-alexander.levin@microsoft.com> In-Reply-To: <20180319161117.17833-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: From: Maurizio Lombardi [ Upstream commit c2dd893a3b0772d1c680e109b9d5715d7f73022b ] 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 ffff882035627d90, but was ffff884= 069541588 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 Acked-by: Chad Dupuis Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- 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 1346e052e03c..8009158a6639 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_UP 0 #define ADAPTER_STATE_GOING_DOWN 1 diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc= _fcoe.c index 72533c58c1f3..2577f8e86be3 100644 --- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c +++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c @@ -641,15 +641,17 @@ static struct fc_host_statistics *bnx2fc_get_host_sta= ts(struct Scsi_Host *shost) if (!fw_stats) return NULL; =20 + mutex_lock(&hba->hba_stats_mutex); + bnx2fc_stats =3D fc_get_host_stats(shost); =20 init_completion(&hba->stat_req_done); if (bnx2fc_send_stat_req(hba)) - return bnx2fc_stats; + goto unlock_stats_mutex; rc =3D 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 +=3D hba->bfw_stats.fc_crc_cnt; @@ -671,6 +673,9 @@ static struct fc_host_statistics *bnx2fc_get_host_stats= (struct Scsi_Host *shost) =20 memcpy(&hba->prev_stats, hba->stats_buffer, sizeof(struct fcoe_statistics_params)); + +unlock_stats_mutex: + mutex_unlock(&hba->hba_stats_mutex); return bnx2fc_stats; } =20 @@ -1303,6 +1308,7 @@ static struct bnx2fc_hba *bnx2fc_hba_create(struct cn= ic_dev *cnic) } spin_lock_init(&hba->hba_lock); mutex_init(&hba->hba_mutex); + mutex_init(&hba->hba_stats_mutex); =20 hba->cnic =3D cnic; =20 --=20 2.14.1