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authorDavid Disseldorp <ddiss@suse.de>2021-07-21 00:55:22 +0200
committerMartin K. Petersen <martin.petersen@oracle.com>2021-07-21 05:18:22 +0200
commita47fa41381a09e5997afd762664db4f5f6657e03 (patch)
treeae8bb707ec8c8a89fbb6d31e4faed343c3b4a6fa
parentscsi: mpt3sas: Transition IOC to Ready state during shutdown (diff)
downloadlinux-a47fa41381a09e5997afd762664db4f5f6657e03.tar.xz
linux-a47fa41381a09e5997afd762664db4f5f6657e03.zip
scsi: target: Fix NULL dereference on XCOPY completion
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>
-rw-r--r--drivers/target/target_core_transport.c2
1 files changed, 1 insertions, 1 deletions
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;