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authorLinus Torvalds <torvalds@linux-foundation.org>2018-09-13 18:52:41 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2018-09-13 18:52:41 -1000
commit145ea6f10d42dac0a1e8a6dfb83b273c0acabf5b (patch)
treecac7179f0f523f2f20d9e9cbe1d100d19b6d7bc5 /fs
parent4624d6ea1b7fe83f1e36caf4537600414ca833f6 (diff)
parent831b624df1b420c8f9281ed1307a8db23afb72df (diff)
downloadlinux-145ea6f10d42dac0a1e8a6dfb83b273c0acabf5b.tar.bz2
Merge tag 'pstore-v4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull pstore fix from Kees Cook: "This fixes a 6 year old pstore bug that everyone just got lucky in avoiding, likely due only using page-aligned persistent ram regions: - Handle page-vs-byte offset handling between iomap and vmap (Bin Yang)" * tag 'pstore-v4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: pstore: Fix incorrect persistent ram buffer mapping
Diffstat (limited to 'fs')
-rw-r--r--fs/pstore/ram_core.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 951a14edcf51..0792595ebcfb 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -429,7 +429,12 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size,
vaddr = vmap(pages, page_count, VM_MAP, prot);
kfree(pages);
- return vaddr;
+ /*
+ * Since vmap() uses page granularity, we must add the offset
+ * into the page here, to get the byte granularity address
+ * into the mapping to represent the actual "start" location.
+ */
+ return vaddr + offset_in_page(start);
}
static void *persistent_ram_iomap(phys_addr_t start, size_t size,
@@ -448,6 +453,11 @@ static void *persistent_ram_iomap(phys_addr_t start, size_t size,
else
va = ioremap_wc(start, size);
+ /*
+ * Since request_mem_region() and ioremap() are byte-granularity
+ * there is no need handle anything special like we do when the
+ * vmap() case in persistent_ram_vmap() above.
+ */
return va;
}
@@ -468,7 +478,7 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
return -ENOMEM;
}
- prz->buffer = prz->vaddr + offset_in_page(start);
+ prz->buffer = prz->vaddr;
prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
return 0;
@@ -515,7 +525,8 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
if (prz->vaddr) {
if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
- vunmap(prz->vaddr);
+ /* We must vunmap() at page-granularity. */
+ vunmap(prz->vaddr - offset_in_page(prz->paddr));
} else {
iounmap(prz->vaddr);
release_mem_region(prz->paddr, prz->size);