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
Showing the changes to include/linux (1 of 2 files). Show all
Unified · Split
| @@ -203,7 +203,10 @@ static inline void pagefault_enable(void) · 202 unmodified lines | ||
| 203 | 203 | /* |
| 204 | 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 | 212 | * The pagefault handler is in general disabled by pagefault_disable() or |