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authorThomas Gleixner <tglx@linutronix.de>2020-11-12 11:59:32 +0100
committerThomas Gleixner <tglx@linutronix.de>2020-11-12 14:44:38 +0100
commit2a656cad337e0e1ca582f58847d7b0c7eeba4dc8 (patch)
tree1c9e527318ff3af65f52d4076da2a2ebfcf2e4f0 /mm/highmem.c
parent13f876ba77ebd5125799bb042201f22cf73df154 (diff)
downloadlinux-2a656cad337e0e1ca582f58847d7b0c7eeba4dc8.tar.bz2
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.c19
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;
}