CPU affinity control added with 39ae3edda325 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.
Fixes: 39ae3edda325 ("scsi: target: core: Make completion affinity configurable")
Signed-off-by: David Disseldorp <ddiss@xxxxxxx>
Cc: Lee Duncan <lduncan@xxxxxxxx>
Cc: Mike Christie <michael.christie@xxxxxxxxxx>
---
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;
--
2.26.2
