| Message ID | 20230524152633.203927-3-deller@gmx.de (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | Fix flush_dcache_page() for usage from irq context on ARM, NIOS2 and PARISC | expand |
Hi Helge, Thanks for the patch. Does it need a Fixes tag? 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 >
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 >>
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)
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(-) -- 2.38.1