2018-09-15 03:43:18

by Jia-Ju Bai

[permalink] [raw]
Subject: [PATCH] scsi: lpfc: Fix a possible sleep-in-atomic-context bug in lpfc_mbuf_alloc()

The driver may sleep with holding a spinlock.
The function call path (from bottom to top) in Linux-4.17 is:

[FUNC] dma_pool_alloc(GFP_KERNEL)
drivers/scsi/lpfc/lpfc_mem.c, 400:
dma_pool_alloc in lpfc_mbuf_alloc
drivers/scsi/lpfc/lpfc_els.c, 228:
lpfc_mbuf_alloc in lpfc_prep_els_iocb
drivers/scsi/lpfc/lpfc_els.c, 2010:
lpfc_prep_els_iocb in lpfc_issue_els_plogi
drivers/scsi/lpfc/lpfc_els.c, 4914:
lpfc_issue_els_plogi in lpfc_els_disc_plogi
drivers/scsi/lpfc/lpfc_els.c, 1486:
lpfc_els_disc_plogi in lpfc_more_plogi
drivers/scsi/lpfc/lpfc_els.c, 3123:
lpfc_more_plogi in lpfc_cancel_retry_delay_tmo
drivers/scsi/lpfc/lpfc_nportdisc.c, 279:
lpfc_cancel_retry_delay_tmo in lpfc_els_abort
drivers/scsi/lpfc/lpfc_nportdisc.c, 236:
spin_lock_irq in lpfc_els_abort

To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.

This bug is found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/scsi/lpfc/lpfc_mem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_mem.c b/drivers/scsi/lpfc/lpfc_mem.c
index 9c22a2c93462..7eae5508bfa3 100644
--- a/drivers/scsi/lpfc/lpfc_mem.c
+++ b/drivers/scsi/lpfc/lpfc_mem.c
@@ -398,7 +398,7 @@ lpfc_mbuf_alloc(struct lpfc_hba *phba, int mem_flags, dma_addr_t *handle)
unsigned long iflags;
void *ret;

- ret = dma_pool_alloc(phba->lpfc_mbuf_pool, GFP_KERNEL, handle);
+ ret = dma_pool_alloc(phba->lpfc_mbuf_pool, GFP_ATOMIC, handle);

spin_lock_irqsave(&phba->hbalock, iflags);
if (!ret && (mem_flags & MEM_PRI) && pool->current_count) {
--
2.17.0