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| author | Thomas Gleixner <tglx@linutronix.de> | 2020-11-12 11:59:32 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-11-12 14:44:38 +0100 |
| commit | 2a656cad337e0e1ca582f58847d7b0c7eeba4dc8 (patch) | |
| tree | 1c9e527318ff3af65f52d4076da2a2ebfcf2e4f0 /mm/highmem.c | |
| parent | highmem: High implementation details and document API (diff) | |
| download | linux-2a656cad337e0e1ca582f58847d7b0c7eeba4dc8.tar.xz linux-2a656cad337e0e1ca582f58847d7b0c7eeba4dc8.zip | |
mm/highmem: Take kmap_high_get() properly into account
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
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/r/87y2j6n8mj.fsf@nanos.tec.linutronix.de
Diffstat (limited to 'mm/highmem.c')
| -rw-r--r-- | mm/highmem.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/mm/highmem.c b/mm/highmem.c index 54bd233846c9..78c481a30c9a 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -426,12 +426,15 @@ static inline void *arch_kmap_local_high_get(struct page *page) #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; } |