Messages in this thread Patch in this message | | | From | Helge Deller <> | Subject | [PATCH 1/3] arm: Fix flush_dcache_page() for usage from irq context | Date | Wed, 24 May 2023 17:26:31 +0200 |
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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 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 Signed-off-by: Helge Deller <deller@gmx.de> --- arch/arm/include/asm/cacheflush.h | 4 ++++ arch/arm/mm/flush.c | 5 +++-- 2 files changed, 7 insertions(+), 2 deletions(-)
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 7ff9feea13a6..d57ec9165520 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 -- 2.38.1
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