The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Possible dependencies:
a43866856125 ("mei: bus: fix unlink on bus in error path") 2cca3465147d ("mei: bus: add client dma interface")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a43866856125c3c432e2fbb6cc63cee1539ec4a7 Mon Sep 17 00:00:00 2001 From: Alexander Usyskin alexander.usyskin@intel.com Date: Tue, 13 Dec 2022 00:02:46 +0200 Subject: [PATCH] mei: bus: fix unlink on bus in error path
Unconditional call to mei_cl_unlink in mei_cl_bus_dev_release leads to call of the mei_cl_unlink without corresponding mei_cl_link. This leads to miscalculation of open_handle_count (decrease without increase).
Call unlink in mei_cldev_enable fail path and remove blanket unlink from mei_cl_bus_dev_release.
Fixes: 34f1166afd67 ("mei: bus: need to unlink client before freeing") Cc: stable@vger.kernel.org Signed-off-by: Alexander Usyskin alexander.usyskin@intel.com Reviewed-by: Tomas Winkler tomas.winkler@intel.com Signed-off-by: Tomas Winkler tomas.winkler@intel.com Link: https://lore.kernel.org/r/20221212220247.286019-1-tomas.winkler@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c index 4a08b624910a..a81b890c7ee6 100644 --- a/drivers/misc/mei/bus.c +++ b/drivers/misc/mei/bus.c @@ -702,13 +702,15 @@ void *mei_cldev_dma_map(struct mei_cl_device *cldev, u8 buffer_id, size_t size) if (cl->state == MEI_FILE_UNINITIALIZED) { ret = mei_cl_link(cl); if (ret) - goto out; + goto notlinked; /* update pointers */ cl->cldev = cldev; }
ret = mei_cl_dma_alloc_and_map(cl, NULL, buffer_id, size); -out: + if (ret) + mei_cl_unlink(cl); +notlinked: mutex_unlock(&bus->device_lock); if (ret) return ERR_PTR(ret); @@ -758,7 +760,7 @@ int mei_cldev_enable(struct mei_cl_device *cldev) if (cl->state == MEI_FILE_UNINITIALIZED) { ret = mei_cl_link(cl); if (ret) - goto out; + goto notlinked; /* update pointers */ cl->cldev = cldev; } @@ -785,6 +787,9 @@ int mei_cldev_enable(struct mei_cl_device *cldev) }
out: + if (ret) + mei_cl_unlink(cl); +notlinked: mutex_unlock(&bus->device_lock);
return ret; @@ -1277,7 +1282,6 @@ static void mei_cl_bus_dev_release(struct device *dev) mei_cl_flush_queues(cldev->cl, NULL); mei_me_cl_put(cldev->me_cl); mei_dev_bus_put(cldev->bus); - mei_cl_unlink(cldev->cl); kfree(cldev->cl); kfree(cldev); }