5.4-stable review patch. If anyone has any objections, please let me know.
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From: Duoming Zhou duoming@zju.edu.cn
[ Upstream commit 60cd16a3b7439ccb699d0bf533799eeb894fd217 ]
During the detaching of Marvell's SAS/SATA controller, the original code calls cancel_delayed_work() in mvs_free() to cancel the delayed work item mwq->work_q. However, if mwq->work_q is already running, the cancel_delayed_work() may fail to cancel it. This can lead to use-after-free scenarios where mvs_free() frees the mvs_info while mvs_work_queue() is still executing and attempts to access the already-freed mvs_info.
A typical race condition is illustrated below:
CPU 0 (remove) | CPU 1 (delayed work callback) mvs_pci_remove() | mvs_free() | mvs_work_queue() cancel_delayed_work() | kfree(mvi) | | mvi-> // UAF
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure that the delayed work item is properly canceled and any executing delayed work item completes before the mvs_info is deallocated.
This bug was found by static analysis.
Fixes: 20b09c2992fe ("[SCSI] mvsas: add support for 94xx; layout change; bug fixes") Signed-off-by: Duoming Zhou duoming@zju.edu.cn Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/mvsas/mv_init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/scsi/mvsas/mv_init.c b/drivers/scsi/mvsas/mv_init.c index 264f32065ea7a..d0a6639c3542d 100644 --- a/drivers/scsi/mvsas/mv_init.c +++ b/drivers/scsi/mvsas/mv_init.c @@ -138,7 +138,7 @@ static void mvs_free(struct mvs_info *mvi) if (mvi->shost) scsi_host_put(mvi->shost); list_for_each_entry(mwq, &mvi->wq_list, entry) - cancel_delayed_work(&mwq->work_q); + cancel_delayed_work_sync(&mwq->work_q); kfree(mvi->rsvd_tags); kfree(mvi); }