Turns out we should have always been disabling preemption here;

someone finally caught it thanks to Peter Z's additional checks.
 
 Cheers,
 Rusty.
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Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module preemption fix from Rusty Russell:
 "Turns out we should have always been disabling preemption here;
  someone finally caught it thanks to Peter Z's additional checks"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  module: Fix locking in symbol_put_addr()
This commit is contained in:
Linus Torvalds 2015-10-28 07:17:50 +09:00
commit 9e17f90702
1 changed files with 6 additions and 2 deletions

View File

@ -1063,11 +1063,15 @@ void symbol_put_addr(void *addr)
if (core_kernel_text(a))
return;
/* module_text_address is safe here: we're supposed to have reference
* to module from symbol_get, so it can't go away. */
/*
* Even though we hold a reference on the module; we still need to
* disable preemption in order to safely traverse the data structure.
*/
preempt_disable();
modaddr = __module_text_address(a);
BUG_ON(!modaddr);
module_put(modaddr);
preempt_enable();
}
EXPORT_SYMBOL_GPL(symbol_put_addr);