WARN_ON_IN_IRQ() assumes that the access_ok() and following user memory access can sleep. But this assumption is not always correct; when the pagefault is disabled, following memory access will just returns -EFAULT and never sleep. Add pagefault_disabled() check in WARN_ON_ONCE() so that it can ignore the case we call it with disabling pagefault. For this purpose, this modified pagefault_disabled() as an inline function. Link: http://lkml.kernel.org/r/155789868664.26965.7932665824135793317.stgit@devnote2
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| @@ -203,7 +203,10 @@ static inline void pagefault_enable(void) · 202 unmodified lines | |||
| 203 | /* | 203 | /* |
| 204 | * Is the pagefault handler disabled? If so, user access methods will not sleep. | 204 | * Is the pagefault handler disabled? If so, user access methods will not sleep. |
| 205 | */ | 205 | */ |
| 206 | #define pagefault_disabled() (current->pagefault_disabled != 0) | 206 | static inline bool pagefault_disabled(void) |
| 207 | { | ||
| 208 | return current->pagefault_disabled != 0; | ||
| 209 | } | ||
| 207 | 210 | ||
| 208 | /* | 211 | /* |
| 209 | * The pagefault handler is in general disabled by pagefault_disable() or | 212 | * The pagefault handler is in general disabled by pagefault_disable() or |