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	 dbefa1f31a
			
		
	
	
		dbefa1f31a
		
	
	
	
	
		
			
			Commitb1fca27d38("kernel debug: support resetting WARN*_ONCE") added support for clearing the state of once warnings. However, it is not functional when CONFIG_LD_DEAD_CODE_DATA_ELIMINATION or CONFIG_LTO_CLANG is enabled, because .data.once matches the .data.[0-9a-zA-Z_]* pattern in the DATA_MAIN macro. Commitcb87481ee8("kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured") was introduced to suppress the issue for the default CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=n case, providing a minimal fix for stable backporting. We were aware this did not address the issue for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. The plan was to apply correct fixes and then revertcb87481ee8. [1] Seven years have passed since then, yet the #ifdef workaround remains in place. Meanwhile, commitb1fca27d38introduced the .data.once section, and commitdc5723b02e("kbuild: add support for Clang LTO") extended the #ifdef. Using a ".." separator in the section name fixes the issue for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION and CONFIG_LTO_CLANG. [1]: https://lore.kernel.org/linux-kbuild/CAK7LNASck6BfdLnESxXUeECYL26yUDm0cwRZuM4gmaWUkxjL5g@mail.gmail.com/ Fixes:b1fca27d38("kernel debug: support resetting WARN*_ONCE") Fixes:dc5723b02e("kbuild: add support for Clang LTO") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
		
			
				
	
	
		
			129 lines
		
	
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			129 lines
		
	
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* SPDX-License-Identifier: GPL-2.0 */
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| #ifndef LINUX_MM_DEBUG_H
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| #define LINUX_MM_DEBUG_H 1
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| 
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| #include <linux/bug.h>
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| #include <linux/stringify.h>
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| 
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| struct page;
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| struct vm_area_struct;
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| struct mm_struct;
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| struct vma_iterator;
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| 
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| void dump_page(const struct page *page, const char *reason);
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| void dump_vma(const struct vm_area_struct *vma);
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| void dump_mm(const struct mm_struct *mm);
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| void vma_iter_dump_tree(const struct vma_iterator *vmi);
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| 
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| #ifdef CONFIG_DEBUG_VM
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| #define VM_BUG_ON(cond) BUG_ON(cond)
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| #define VM_BUG_ON_PAGE(cond, page)					\
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| 	do {								\
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| 		if (unlikely(cond)) {					\
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| 			dump_page(page, "VM_BUG_ON_PAGE(" __stringify(cond)")");\
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| 			BUG();						\
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| 		}							\
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| 	} while (0)
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| #define VM_BUG_ON_FOLIO(cond, folio)					\
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| 	do {								\
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| 		if (unlikely(cond)) {					\
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| 			dump_page(&folio->page, "VM_BUG_ON_FOLIO(" __stringify(cond)")");\
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| 			BUG();						\
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| 		}							\
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| 	} while (0)
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| #define VM_BUG_ON_VMA(cond, vma)					\
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| 	do {								\
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| 		if (unlikely(cond)) {					\
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| 			dump_vma(vma);					\
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| 			BUG();						\
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| 		}							\
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| 	} while (0)
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| #define VM_BUG_ON_MM(cond, mm)						\
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| 	do {								\
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| 		if (unlikely(cond)) {					\
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| 			dump_mm(mm);					\
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| 			BUG();						\
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| 		}							\
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| 	} while (0)
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| #define VM_WARN_ON_ONCE_PAGE(cond, page)	({			\
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| 	static bool __section(".data..once") __warned;			\
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| 	int __ret_warn_once = !!(cond);					\
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| 									\
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| 	if (unlikely(__ret_warn_once && !__warned)) {			\
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| 		dump_page(page, "VM_WARN_ON_ONCE_PAGE(" __stringify(cond)")");\
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| 		__warned = true;					\
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| 		WARN_ON(1);						\
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| 	}								\
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| 	unlikely(__ret_warn_once);					\
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| })
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| #define VM_WARN_ON_FOLIO(cond, folio)		({			\
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| 	int __ret_warn = !!(cond);					\
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| 									\
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| 	if (unlikely(__ret_warn)) {					\
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| 		dump_page(&folio->page, "VM_WARN_ON_FOLIO(" __stringify(cond)")");\
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| 		WARN_ON(1);						\
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| 	}								\
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| 	unlikely(__ret_warn);						\
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| })
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| #define VM_WARN_ON_ONCE_FOLIO(cond, folio)	({			\
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| 	static bool __section(".data..once") __warned;			\
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| 	int __ret_warn_once = !!(cond);					\
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| 									\
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| 	if (unlikely(__ret_warn_once && !__warned)) {			\
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| 		dump_page(&folio->page, "VM_WARN_ON_ONCE_FOLIO(" __stringify(cond)")");\
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| 		__warned = true;					\
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| 		WARN_ON(1);						\
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| 	}								\
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| 	unlikely(__ret_warn_once);					\
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| })
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| #define VM_WARN_ON_ONCE_MM(cond, mm)		({			\
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| 	static bool __section(".data..once") __warned;			\
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| 	int __ret_warn_once = !!(cond);					\
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| 									\
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| 	if (unlikely(__ret_warn_once && !__warned)) {			\
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| 		dump_mm(mm);						\
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| 		__warned = true;					\
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| 		WARN_ON(1);						\
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| 	}								\
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| 	unlikely(__ret_warn_once);					\
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| })
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| 
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| #define VM_WARN_ON(cond) (void)WARN_ON(cond)
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| #define VM_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
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| #define VM_WARN_ONCE(cond, format...) (void)WARN_ONCE(cond, format)
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| #define VM_WARN(cond, format...) (void)WARN(cond, format)
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| #else
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| #define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
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| #define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)
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| #define VM_BUG_ON_FOLIO(cond, folio) VM_BUG_ON(cond)
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| #define VM_BUG_ON_VMA(cond, vma) VM_BUG_ON(cond)
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| #define VM_BUG_ON_MM(cond, mm) VM_BUG_ON(cond)
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| #define VM_WARN_ON(cond) BUILD_BUG_ON_INVALID(cond)
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| #define VM_WARN_ON_ONCE(cond) BUILD_BUG_ON_INVALID(cond)
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| #define VM_WARN_ON_ONCE_PAGE(cond, page)  BUILD_BUG_ON_INVALID(cond)
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| #define VM_WARN_ON_FOLIO(cond, folio)  BUILD_BUG_ON_INVALID(cond)
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| #define VM_WARN_ON_ONCE_FOLIO(cond, folio)  BUILD_BUG_ON_INVALID(cond)
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| #define VM_WARN_ON_ONCE_MM(cond, mm)  BUILD_BUG_ON_INVALID(cond)
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| #define VM_WARN_ONCE(cond, format...) BUILD_BUG_ON_INVALID(cond)
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| #define VM_WARN(cond, format...) BUILD_BUG_ON_INVALID(cond)
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| #endif
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| 
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| #ifdef CONFIG_DEBUG_VM_IRQSOFF
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| #define VM_WARN_ON_IRQS_ENABLED() WARN_ON_ONCE(!irqs_disabled())
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| #else
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| #define VM_WARN_ON_IRQS_ENABLED() do { } while (0)
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| #endif
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| 
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| #ifdef CONFIG_DEBUG_VIRTUAL
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| #define VIRTUAL_BUG_ON(cond) BUG_ON(cond)
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| #else
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| #define VIRTUAL_BUG_ON(cond) do { } while (0)
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| #endif
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| 
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| #ifdef CONFIG_DEBUG_VM_PGFLAGS
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| #define VM_BUG_ON_PGFLAGS(cond, page) VM_BUG_ON_PAGE(cond, page)
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| #else
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| #define VM_BUG_ON_PGFLAGS(cond, page) BUILD_BUG_ON_INVALID(cond)
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| #endif
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| 
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| #endif
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