On Mon, 4 Aug 2025 at 03:36, Jiayi Li lijiayi@kylinos.cn wrote:
The existing memstick core patch: commit 62c59a8786e6 ("memstick: Skip allocating card when removing host") sets host->removing in memstick_remove_host(),but still exists a critical time window where memstick_check can run after host->eject is set but before removing is set.
In the rtsx_usb_ms driver, the problematic sequence is:
rtsx_usb_ms_drv_remove: memstick_check: host->eject = true cancel_work_sync(handle_req) if(!host->removing) ... memstick_alloc_card() memstick_set_rw_addr() memstick_new_req() rtsx_usb_ms_request() if(!host->eject) skip schedule_work wait_for_completion() memstick_remove_host: [blocks indefinitely] host->removing = true flush_workqueue() [block]
- rtsx_usb_ms_drv_remove sets host->eject = true
- cancel_work_sync(&host->handle_req) runs
- memstick_check work may be executed here <-- danger window
- memstick_remove_host sets removing = 1
During this window (step 3), memstick_check calls memstick_alloc_card, which may indefinitely waiting for mrq_complete completion that will never occur because rtsx_usb_ms_request sees eject=true and skips scheduling work, memstick_set_rw_addr waits forever for completion.
This causes a deadlock when memstick_remove_host tries to flush_workqueue, waiting for memstick_check to complete, while memstick_check is blocked waiting for mrq_complete completion.
Fix this by setting removing=true at the start of rtsx_usb_ms_drv_remove, before any work cancellation. This ensures memstick_check will see the removing flag immediately and exit early, avoiding the deadlock.
Fixes: 62c59a8786e6 ("memstick: Skip allocating card when removing host") Signed-off-by: Jiayi Li lijiayi@kylinos.cn Cc: stable@vger.kernel.org
Applied for fixes, thanks!
Kind regards Uffe
v1 -> v2: Added Cc: stable@vger.kernel.org
drivers/memstick/core/memstick.c | 1 - drivers/memstick/host/rtsx_usb_ms.c | 1 + 2 files changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c index 043b9ec756ff..95e65f4958f2 100644 --- a/drivers/memstick/core/memstick.c +++ b/drivers/memstick/core/memstick.c @@ -555,7 +555,6 @@ EXPORT_SYMBOL(memstick_add_host); */ void memstick_remove_host(struct memstick_host *host) {
host->removing = 1; flush_workqueue(workqueue); mutex_lock(&host->lock); if (host->card)diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c index 3878136227e4..5b5e9354fb2e 100644 --- a/drivers/memstick/host/rtsx_usb_ms.c +++ b/drivers/memstick/host/rtsx_usb_ms.c @@ -812,6 +812,7 @@ static void rtsx_usb_ms_drv_remove(struct platform_device *pdev) int err;
host->eject = true;
msh->removing = true; cancel_work_sync(&host->handle_req); cancel_delayed_work_sync(&host->poll_card);-- 2.47.1