| From e588e16f0f8644bda153699767cfe75ad72e98de Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 21 Jul 2021 00:55:22 +0200 |
| Subject: scsi: target: Fix NULL dereference on XCOPY completion |
| |
| From: David Disseldorp <ddiss@suse.de> |
| |
| [ Upstream commit a47fa41381a09e5997afd762664db4f5f6657e03 ] |
| |
| CPU affinity control added with commit 39ae3edda325 ("scsi: target: core: |
| Make completion affinity configurable") makes target_complete_cmd() queue |
| work on a CPU based on se_tpg->se_tpg_wwn->cmd_compl_affinity state. |
| |
| LIO's EXTENDED COPY worker is a special case in that read/write cmds are |
| dispatched using the global xcopy_pt_tpg, which carries a NULL se_tpg_wwn |
| pointer following initialization in target_xcopy_setup_pt(). |
| |
| The NULL xcopy_pt_tpg->se_tpg_wwn pointer is dereferenced on completion of |
| any EXTENDED COPY initiated read/write cmds. E.g using the libiscsi |
| SCSI.ExtendedCopy.Simple test: |
| |
| BUG: kernel NULL pointer dereference, address: 00000000000001a8 |
| RIP: 0010:target_complete_cmd+0x9d/0x130 [target_core_mod] |
| Call Trace: |
| fd_execute_rw+0x148/0x42a [target_core_file] |
| ? __dynamic_pr_debug+0xa7/0xe0 |
| ? target_check_reservation+0x5b/0x940 [target_core_mod] |
| __target_execute_cmd+0x1e/0x90 [target_core_mod] |
| transport_generic_new_cmd+0x17c/0x330 [target_core_mod] |
| target_xcopy_issue_pt_cmd+0x9/0x60 [target_core_mod] |
| target_xcopy_read_source.isra.7+0x10b/0x1b0 [target_core_mod] |
| ? target_check_fua+0x40/0x40 [target_core_mod] |
| ? transport_complete_task_attr+0x130/0x130 [target_core_mod] |
| target_xcopy_do_work+0x61f/0xc00 [target_core_mod] |
| |
| This fix makes target_complete_cmd() queue work on se_cmd->cpuid if |
| se_tpg_wwn is NULL. |
| |
| Link: https://lore.kernel.org/r/20210720225522.26291-1-ddiss@suse.de |
| Fixes: 39ae3edda325 ("scsi: target: core: Make completion affinity configurable") |
| Cc: Lee Duncan <lduncan@suse.com> |
| Cc: Mike Christie <michael.christie@oracle.com> |
| Reviewed-by: Mike Christie <michael.christie@oracle.com> |
| Signed-off-by: David Disseldorp <ddiss@suse.de> |
| Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/target/target_core_transport.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c |
| index 7e35eddd9eb7..26ceabe34de5 100644 |
| --- a/drivers/target/target_core_transport.c |
| +++ b/drivers/target/target_core_transport.c |
| @@ -886,7 +886,7 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status) |
| INIT_WORK(&cmd->work, success ? target_complete_ok_work : |
| target_complete_failure_work); |
| |
| - if (wwn->cmd_compl_affinity == SE_COMPL_AFFINITY_CPUID) |
| + if (!wwn || wwn->cmd_compl_affinity == SE_COMPL_AFFINITY_CPUID) |
| cpu = cmd->cpuid; |
| else |
| cpu = wwn->cmd_compl_affinity; |
| -- |
| 2.30.2 |
| |