Messages in this thread | | | Date | Mon, 19 Jun 2023 12:10:26 +0200 | Subject | Re: [PATCH 2/3] nios2: Fix flush_dcache_page() for usage from irq context | From | Helge Deller <> |
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Hi Dinh,
On 6/14/23 00:39, Dinh Nguyen wrote: > Thanks for the patch. Does it need a Fixes tag?
I did not add a fixes tag for the parisc or arm version.
The code was originally correct, but later patches then suddenly started using cache flushes from irq context (e.g. 21b40200cfe96 ("aio: use flush_dcache_page()")) which then triggers the bug. So, it's hard to say that it fixes one specific commit.
I suggest you backport it as far as possible.
Helge
> Dinh > > On 5/24/23 10:26, Helge Deller wrote: >> 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 NIOS2 >> 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: Dinh Nguyen <dinguyen@kernel.org> >> Signed-off-by: Helge Deller <deller@gmx.de> >> --- >> arch/nios2/include/asm/cacheflush.h | 4 ++++ >> arch/nios2/mm/cacheflush.c | 5 +++-- >> 2 files changed, 7 insertions(+), 2 deletions(-) >> >> diff --git a/arch/nios2/include/asm/cacheflush.h b/arch/nios2/include/asm/cacheflush.h >> index d0b71dd71287..a37242662809 100644 >> --- a/arch/nios2/include/asm/cacheflush.h >> +++ b/arch/nios2/include/asm/cacheflush.h >> @@ -48,5 +48,9 @@ extern void invalidate_dcache_range(unsigned long start, unsigned long end); >> >> #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) >> >> #endif /* _ASM_NIOS2_CACHEFLUSH_H */ >> diff --git a/arch/nios2/mm/cacheflush.c b/arch/nios2/mm/cacheflush.c >> index 6aa9257c3ede..35f3b599187f 100644 >> --- a/arch/nios2/mm/cacheflush.c >> +++ b/arch/nios2/mm/cacheflush.c >> @@ -75,11 +75,12 @@ static void flush_aliases(struct address_space *mapping, struct page *page) >> { >> struct mm_struct *mm = current->active_mm; >> struct vm_area_struct *mpnt; >> + unsigned long flags; >> pgoff_t pgoff; >> >> 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; >> >> @@ -92,7 +93,7 @@ static void flush_aliases(struct address_space *mapping, struct page *page) >> flush_cache_page(mpnt, mpnt->vm_start + offset, >> page_to_pfn(page)); >> } >> - flush_dcache_mmap_unlock(mapping); >> + flush_dcache_mmap_unlock_irqrestore(mapping, flags); >> } >> >> void flush_cache_all(void) >> -- >> 2.38.1 >>
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