From: michael.christie@oracle.com
To: David Disseldorp <ddiss@suse.de>, target-devel@vger.kernel.org
Cc: martin.petersen@oracle.com, Lee Duncan <lduncan@suse.com>
Subject: Re: [PATCH] scsi: target: fix NULL dereference on XCOPY completion
Date: Tue, 20 Jul 2021 19:22:30 -0500 [thread overview]
Message-ID: <5368a04b-bee8-8ecc-f47e-29abd1cd0de8@oracle.com> (raw)
In-Reply-To: <20210720225522.26291-1-ddiss@suse.de>
On 7/20/21 5:55 PM, David Disseldorp wrote:
> 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@suse.de>
> Cc: Lee Duncan <lduncan@suse.com>
> Cc: Mike Christie <michael.christie@oracle.com>
> ---
> 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;
>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
next prev parent reply other threads:[~2021-07-21 0:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-20 22:55 [PATCH] scsi: target: fix NULL dereference on XCOPY completion David Disseldorp
2021-07-21 0:22 ` michael.christie [this message]
2021-07-21 3:22 ` Martin K. Petersen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5368a04b-bee8-8ecc-f47e-29abd1cd0de8@oracle.com \
--to=michael.christie@oracle.com \
--cc=ddiss@suse.de \
--cc=lduncan@suse.com \
--cc=martin.petersen@oracle.com \
--cc=target-devel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.