The patch titled
ibmphp: fix module ref count underflow
has been added to the -mm tree. Its filename is
ibmphp-fix-module-ref-count-underflow.patch
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------------------------------------------------------
Subject: ibmphp: fix module ref count underflow
From: Neil Horman <nhorman@xxxxxxxxxxxxx>
The ibmphp hotplug driver does something rather silly in its init routine.
It purposely calls module_put so as to underflow its module ref count to
avoid being removed from the kernel.
This is bad practice, and wrong, since it provides a window for subsequent
module_gets to reset the refcount to zero, allowing an unload to race in
and cause all sorts of mysterious panics. If the module is unsafe to
load, it should inform the kernel as such with a call to __unsafe. The
patch does that.
Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/pci/hotplug/ibmphp_core.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff -puN drivers/pci/hotplug/ibmphp_core.c~ibmphp-fix-module-ref-count-underflow drivers/pci/hotplug/ibmphp_core.c
--- a/drivers/pci/hotplug/ibmphp_core.c~ibmphp-fix-module-ref-count-underflow
+++ a/drivers/pci/hotplug/ibmphp_core.c
@@ -1402,9 +1402,11 @@ static int __init ibmphp_init(void)
goto error;
}
- /* lock ourselves into memory with a module
- * count of -1 so that no one can unload us. */
- module_put(THIS_MODULE);
+ /*
+ * Its unsafe to unload this module, so tell
+ * the kernel to avoid inadvertent unloads
+ */
+ __unsafe(THIS_MODULE);
exit:
return rc;
_
Patches currently in -mm which might be from nhorman@xxxxxxxxxxxxx are
linux-next.patch
ibmphp-fix-module-ref-count-underflow.patch
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