6.12-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 ab58153ec64fa3fc9aea09ca09dc9322e0b54a7c ]
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 duoming@zju.edu.cn Link: https://patch.msgid.link/20251028100149.40721-1-duoming@zju.edu.cn Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/imm.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/scsi/imm.c b/drivers/scsi/imm.c index 1d4c7310f1a63..d77490e2d7bc8 100644 --- a/drivers/scsi/imm.c +++ b/drivers/scsi/imm.c @@ -1261,6 +1261,7 @@ 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);