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tcm_fc: Fix free-after-use regression in ft_free_cmd

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commit ed8ec8f707 upstream.

This patch fixes a free-after-use regression in ft_free_cmd(), where
ft_sess_put() is called with cmd->sess after percpu_ida_free() has
already released the tag.

Fix this bug by saving the ft_sess pointer ahead of percpu_ida_free(),
and pass it directly to ft_sess_put().

The regression was originally introduced in v3.13-rc1 commit:

  commit 5f544cfac9
  Author: Nicholas Bellinger <nab@daterainc.com>
  Date:   Mon Sep 23 12:12:42 2013 -0700

      tcm_fc: Convert to per-cpu command map pre-allocation of ft_cmd

Reported-by: Jun Wu <jwu@stormojo.com>
Cc: Mark Rustad <mark.d.rustad@intel.com>
Cc: Robert Love <robert.w.love@intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nicholas Bellinger 2014-05-12 12:18:32 -07:00 committed by Greg Kroah-Hartman
parent 8b9df249dd
commit 17edcf1972
1 changed files with 4 additions and 4 deletions
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8
drivers/target/tcm_fc/tfc_cmd.c
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@ -90,18 +90,18 @@ static void ft_free_cmd(struct ft_cmd *cmd)
{
struct fc_frame *fp;
struct fc_lport *lport;
struct se_session *se_sess;
struct ft_sess *sess;
if (!cmd)
return;
se_sess = cmd->sess->se_sess;
sess = cmd->sess;
fp = cmd->req_frame;
lport = fr_dev(fp);
if (fr_seq(fp))
lport->tt.seq_release(fr_seq(fp));
fc_frame_free(fp);
percpu_ida_free(&se_sess->sess_tag_pool, cmd->se_cmd.map_tag);
ft_sess_put(cmd->sess); /* undo get from lookup at recv */
percpu_ida_free(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag);
ft_sess_put(sess); /* undo get from lookup at recv */
}
void ft_release_cmd(struct se_cmd *se_cmd)