From ab58153ec64fa3fc9aea09ca09dc9322e0b54a7c Mon Sep 17 00:00:00 2001 From: Duoming Zhou Date: Tue, 28 Oct 2025 18:01:49 +0800 Subject: [PATCH] scsi: imm: Fix use-after-free bug caused by unfinished delayed work The delayed work item 'imm_tq' is initialized in imm_attach() and scheduled via imm_queuecommand() for processing SCSI commands. When the IMM parallel port SCSI host adapter is detached through imm_detach(), the imm_struct device instance is deallocated. However, the delayed work might still be pending or executing when imm_detach() is called, leading to use-after-free bugs when the work function imm_interrupt() accesses the already freed imm_struct memory. The race condition can occur as follows: CPU 0(detach thread) | CPU 1 | imm_queuecommand() | imm_queuecommand_lck() imm_detach() | schedule_delayed_work() kfree(dev) //FREE | imm_interrupt() | dev = container_of(...) //USE dev-> //USE Add disable_delayed_work_sync() in imm_detach() to guarantee proper cancellation of the delayed work item before imm_struct is deallocated. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Duoming Zhou Link: https://patch.msgid.link/20251028100149.40721-1-duoming@zju.edu.cn Signed-off-by: Martin K. Petersen --- drivers/scsi/imm.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/scsi/imm.c b/drivers/scsi/imm.c index 5c602c0577989..45b0e33293a59 100644 --- a/drivers/scsi/imm.c +++ b/drivers/scsi/imm.c @@ -1260,6 +1260,7 @@ static void imm_detach(struct parport *pb) imm_struct *dev; list_for_each_entry(dev, &imm_hosts, list) { if (dev->dev->port == pb) { + disable_delayed_work_sync(&dev->imm_tq); list_del_init(&dev->list); scsi_remove_host(dev->host); scsi_host_put(dev->host); -- 2.47.3