6.12-stable review patch. If anyone has any objections, please let me know.
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From: Justin Tee justin.tee@broadcom.com
[ Upstream commit b5162bb6aa1ec04dff4509b025883524b6d7e7ca ]
Smatch detected a potential use-after-free of an ndlp oject in dev_loss_tmo_callbk during driver unload or fatal error handling.
Fix by reordering code to avoid potential use-after-free if initial nodelist reference has been previously removed.
Fixes: 4281f44ea8bf ("scsi: lpfc: Prevent NDLP reference count underflow in dev_loss_tmo callback") Reported-by: Dan Carpenter dan.carpenter@linaro.org Closes: https://lore.kernel.org/linux-scsi/41c1d855-9eb5-416f-ac12-8b61929201a3@stan... Signed-off-by: Justin Tee justin.tee@broadcom.com Link: https://lore.kernel.org/r/20250425194806.3585-6-justintee8345@gmail.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/lpfc/lpfc_hbadisc.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-)
diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c index 5297122f89fc8..b5dd17eecf82d 100644 --- a/drivers/scsi/lpfc/lpfc_hbadisc.c +++ b/drivers/scsi/lpfc/lpfc_hbadisc.c @@ -155,7 +155,7 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport) struct lpfc_hba *phba; struct lpfc_work_evt *evtp; unsigned long iflags; - bool nvme_reg = false; + bool drop_initial_node_ref = false;
ndlp = ((struct lpfc_rport_data *)rport->dd_data)->pnode; if (!ndlp) @@ -182,8 +182,13 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport) spin_lock_irqsave(&ndlp->lock, iflags); ndlp->rport = NULL;
- if (ndlp->fc4_xpt_flags & NVME_XPT_REGD) - nvme_reg = true; + /* Only 1 thread can drop the initial node reference. + * If not registered for NVME and NLP_DROPPED flag is + * clear, remove the initial reference. + */ + if (!(ndlp->fc4_xpt_flags & NVME_XPT_REGD)) + if (!test_and_set_bit(NLP_DROPPED, &ndlp->nlp_flag)) + drop_initial_node_ref = true;
/* The scsi_transport is done with the rport so lpfc cannot * call to unregister. @@ -194,13 +199,16 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport) /* If NLP_XPT_REGD was cleared in lpfc_nlp_unreg_node, * unregister calls were made to the scsi and nvme * transports and refcnt was already decremented. Clear - * the NLP_XPT_REGD flag only if the NVME Rport is + * the NLP_XPT_REGD flag only if the NVME nrport is * confirmed unregistered. */ - if (!nvme_reg && ndlp->fc4_xpt_flags & NLP_XPT_REGD) { - ndlp->fc4_xpt_flags &= ~NLP_XPT_REGD; + if (ndlp->fc4_xpt_flags & NLP_XPT_REGD) { + if (!(ndlp->fc4_xpt_flags & NVME_XPT_REGD)) + ndlp->fc4_xpt_flags &= ~NLP_XPT_REGD; spin_unlock_irqrestore(&ndlp->lock, iflags); - lpfc_nlp_put(ndlp); /* may free ndlp */ + + /* Release scsi transport reference */ + lpfc_nlp_put(ndlp); } else { spin_unlock_irqrestore(&ndlp->lock, iflags); } @@ -208,14 +216,8 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport) spin_unlock_irqrestore(&ndlp->lock, iflags); }
- /* Only 1 thread can drop the initial node reference. If - * another thread has set NLP_DROPPED, this thread is done. - */ - if (nvme_reg || test_bit(NLP_DROPPED, &ndlp->nlp_flag)) - return; - - set_bit(NLP_DROPPED, &ndlp->nlp_flag); - lpfc_nlp_put(ndlp); + if (drop_initial_node_ref) + lpfc_nlp_put(ndlp); return; }