| Message ID | 87y2j6n8mj.fsf@nanos.tec.linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/highmem: Take kmap_high_get() properly into account | expand |
Hi Thomas, On 12.11.2020 11:59, Thomas Gleixner wrote: > kunmap_local() warns when the virtual address to unmap is below > PAGE_OFFSET. This is correct except for the case that the mapping was > obtained via kmap_high_get() because the PKMAP addresses are right below > PAGE_OFFSET. > > Cure it by skipping the WARN_ON() when the unmap was handled by > kunmap_high(). > > Fixes: 298fa1ad5571 ("highmem: Provide generic variant of kmap_atomic*") > Reported-by: vtolkm@googlemail.com > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> This fixes the issue I've reported here: https://lore.kernel.org/dri-devel/c07bae0c-68dd-2693-948f-00e8a50f3053@samsung.com/ Thanks! Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> > --- > mm/highmem.c | 19 +++++++++++++------ > 1 file changed, 13 insertions(+), 6 deletions(-) > > --- a/mm/highmem.c > +++ b/mm/highmem.c > @@ -426,12 +426,15 @@ static inline void *arch_kmap_local_high > #endif > > /* Unmap a local mapping which was obtained by kmap_high_get() */ > -static inline void kmap_high_unmap_local(unsigned long vaddr) > +static inline bool kmap_high_unmap_local(unsigned long vaddr) > { > #ifdef ARCH_NEEDS_KMAP_HIGH_GET > - if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) > + if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) { > kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)])); > + return true; > + } > #endif > + return false; > } > > static inline int kmap_local_calc_idx(int idx) > @@ -491,10 +494,14 @@ void kunmap_local_indexed(void *vaddr) > > if (addr < __fix_to_virt(FIX_KMAP_END) || > addr > __fix_to_virt(FIX_KMAP_BEGIN)) { > - WARN_ON_ONCE(addr < PAGE_OFFSET); > - > - /* Handle mappings which were obtained by kmap_high_get() */ > - kmap_high_unmap_local(addr); > + /* > + * Handle mappings which were obtained by kmap_high_get() > + * first as the virtual address of such mappings is below > + * PAGE_OFFSET. Warn for all other addresses which are in > + * the user space part of the virtual address space. > + */ > + if (!kmap_high_unmap_local(addr)) > + WARN_ON_ONCE(addr < PAGE_OFFSET); > return; > } > > > > Best regards
--- a/mm/highmem.c +++ b/mm/highmem.c @@ -426,12 +426,15 @@ static inline void *arch_kmap_local_high #endif /* Unmap a local mapping which was obtained by kmap_high_get() */ -static inline void kmap_high_unmap_local(unsigned long vaddr) +static inline bool kmap_high_unmap_local(unsigned long vaddr) { #ifdef ARCH_NEEDS_KMAP_HIGH_GET - if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) + if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) { kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)])); + return true; + } #endif + return false; } static inline int kmap_local_calc_idx(int idx) @@ -491,10 +494,14 @@ void kunmap_local_indexed(void *vaddr) if (addr < __fix_to_virt(FIX_KMAP_END) || addr > __fix_to_virt(FIX_KMAP_BEGIN)) { - WARN_ON_ONCE(addr < PAGE_OFFSET); - - /* Handle mappings which were obtained by kmap_high_get() */ - kmap_high_unmap_local(addr); + /* + * Handle mappings which were obtained by kmap_high_get() + * first as the virtual address of such mappings is below + * PAGE_OFFSET. Warn for all other addresses which are in + * the user space part of the virtual address space. + */ + if (!kmap_high_unmap_local(addr)) + WARN_ON_ONCE(addr < PAGE_OFFSET); return; }
kunmap_local() warns when the virtual address to unmap is below PAGE_OFFSET. This is correct except for the case that the mapping was obtained via kmap_high_get() because the PKMAP addresses are right below PAGE_OFFSET. Cure it by skipping the WARN_ON() when the unmap was handled by kunmap_high(). Fixes: 298fa1ad5571 ("highmem: Provide generic variant of kmap_atomic*") Reported-by: vtolkm@googlemail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- mm/highmem.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)