Messages in this thread Patch in this message | | | Subject | module: fix module_refcount() return when running in a module exit routine | From | James Bottomley <> | Date | Sun, 18 Jan 2015 08:55:46 -0800 |
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From: James Bottomley <JBottomley@Parallels.com>
After e513cc1 module: Remove stop_machine from module unloading, module_refcount() is returning (unsigned long)-1 when called from within a routine that runs in module_exit. This is confusing the scsi device put code which is coded to detect a module_refcount() of zero for running within a module exit routine and not try to do another module_put. The fix is to restore the original behaviour of module_refcount() and return zero if we're running inside an exit routine.
Fixes: e513cc1c07e2ab93a4514eec9833e031df3e30bb Reported-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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diff --git a/kernel/module.c b/kernel/module.c index 3965511..c33a113 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -774,7 +774,12 @@ static int try_stop_module(struct module *mod, int flags, int *forced) unsigned long module_refcount(struct module *mod) { - return (unsigned long)atomic_read(&mod->refcnt) - MODULE_REF_BASE; + unsigned long ret = atomic_read(&mod->refcnt); + + if (ret == 0) + /* ref is already zero (probably in module exit) */ + return 0; + return ret - MODULE_REF_BASE; } EXPORT_SYMBOL(module_refcount);
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