On 2021/9/11 12:38 上午, Mike Christie wrote:
On 9/9/21 8:02 PM, Ding Hui wrote:like commit 5db6dd14b313 ("scsi: libiscsi: Fix NULL pointer dereference in iscsi_eh_session_reset"), access conn->persistent_address here is not safe too. The persistent_address is independent of conn refcount, so maybe already freed by iscsi_conn_teardown(), also we put the refcount of conn above, the conn pointer may be invalid.This shouldn't happen like you describe above, because when we wake up we will see the session->state is ISCSI_STATE_TERMINATE. We will then not reference the conn in that code below. However, it looks like we could hit an issue where if a user was resetting the persistent_address or targetname via iscsi_set_param -> iscsi_switch_str_param then we could be accessing freed memory. I think we need the frwd_lock when swapping the strings in iscsi_switch_str_param.
Thanks for your detailed explanation, I'll drop 2/3 and 3/3 in v2 patch. I expect that the persistent_address issue be fixed in your future patchset. Sorry for my ignorance.
Signed-off-by: Ding Hui <dinghui@xxxxxxxxxxxxxx> --- drivers/scsi/libiscsi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index 712a45368385..69b3b2148328 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -2531,8 +2531,8 @@ int iscsi_eh_session_reset(struct scsi_cmnd *sc) spin_lock_bh(&session->frwd_lock); if (session->state == ISCSI_STATE_LOGGED_IN) { ISCSI_DBG_EH(session, - "session reset succeeded for %s,%s\n", - session->targetname, conn->persistent_address); + "session reset succeeded for %s\n", + session->targetname); } else goto failed; spin_unlock_bh(&session->frwd_lock);
-- Thanks, -dinghui
