Messages in this thread Patch in this message | | | Date | Fri, 18 Aug 2023 22:58:09 +0200 | From | Helge Deller <> | Subject | [PATCH][RESEND] arm: Fix flush_dcache_page() for usage from irq context |
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Since at least kernel 6.1, flush_dcache_page() is called with IRQs disabled, e.g. from aio_complete().
But the current implementation for flush_dcache_page() on ARM (32-bit) unintentionally re-enables IRQs, which may lead to deadlocks.
Fix it by using xa_lock_irqsave() and xa_unlock_irqrestore() for the flush_dcache_mmap_*lock() macros instead.
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-arm-kernel@lists.infradead.org Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Helge Deller <deller@gmx.de>
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diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h index a094f964c869..5b8a1ef0dc50 100644 --- a/arch/arm/include/asm/cacheflush.h +++ b/arch/arm/include/asm/cacheflush.h @@ -315,6 +315,10 @@ static inline void flush_anon_page(struct vm_area_struct *vma, #define flush_dcache_mmap_lock(mapping) xa_lock_irq(&mapping->i_pages) #define flush_dcache_mmap_unlock(mapping) xa_unlock_irq(&mapping->i_pages) +#define flush_dcache_mmap_lock_irqsave(mapping, flags) \ + xa_lock_irqsave(&mapping->i_pages, flags) +#define flush_dcache_mmap_unlock_irqrestore(mapping, flags) \ + xa_unlock_irqrestore(&mapping->i_pages, flags) /* * We don't appear to need to do anything here. In fact, if we did, we'd diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 2508be91b7a0..e70dd5e354ae 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -238,6 +238,7 @@ static void __flush_dcache_aliases(struct address_space *mapping, struct page *p { struct mm_struct *mm = current->active_mm; struct vm_area_struct *mpnt; + unsigned long flags; pgoff_t pgoff; /* @@ -248,7 +249,7 @@ static void __flush_dcache_aliases(struct address_space *mapping, struct page *p */ pgoff = page->index; - flush_dcache_mmap_lock(mapping); + flush_dcache_mmap_lock_irqsave(mapping, flags); vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) { unsigned long offset; @@ -262,7 +263,7 @@ static void __flush_dcache_aliases(struct address_space *mapping, struct page *p offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT; flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page)); } - flush_dcache_mmap_unlock(mapping); + flush_dcache_mmap_unlock_irqrestore(mapping, flags); } #if __LINUX_ARM_ARCH__ >= 6
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