powerpc: Fix oops when echoing bad values to /sys/devices/system/memory/probe

commit a11940978bd598e65996b4f807cf4904793f7025 upstream.

If we echo an address the hypervisor doesn't like to
/sys/devices/system/memory/probe we oops the box:

# echo 0x10000000000 > /sys/devices/system/memory/probe

kernel BUG at arch/powerpc/mm/hash_utils_64.c:541!

The backtrace is:

create_section_mapping
arch_add_memory
add_memory
memory_probe_store
sysdev_class_store
sysfs_write_file
vfs_write
SyS_write

In create_section_mapping we BUG if htab_bolt_mapping returned
an error. A better approach is to return an error which will
propagate back to userspace.

Rerunning the test with this patch applied:

# echo 0x10000000000 > /sys/devices/system/memory/probe
-bash: echo: write error: Invalid argument

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/powerpc/include/asm/sparsemem.h b/arch/powerpc/include/asm/sparsemem.h
index 54a47ea..0c5fa31 100644 (file)
--- a/arch/powerpc/include/asm/sparsemem.h
+++ b/arch/powerpc/include/asm/sparsemem.h
@@ -16,7 +16,7 @@
 #endif /* CONFIG_SPARSEMEM */
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-extern void create_section_mapping(unsigned long start, unsigned long end);
+extern int create_section_mapping(unsigned long start, unsigned long end);
 extern int remove_section_mapping(unsigned long start, unsigned long end);
 #ifdef CONFIG_NUMA
 extern int hot_add_scn_to_nid(unsigned long scn_addr);

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 26b2872..07f9e9f 100644 (file)
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -534,11 +534,11 @@ static unsigned long __init htab_get_table_size(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-void create_section_mapping(unsigned long start, unsigned long end)
+int create_section_mapping(unsigned long start, unsigned long end)
 {
-       BUG_ON(htab_bolt_mapping(start, end, __pa(start),
+       return htab_bolt_mapping(start, end, __pa(start),
                                 pgprot_val(PAGE_KERNEL), mmu_linear_psize,
-                                mmu_kernel_ssize));
+                                mmu_kernel_ssize);
 }
 
 int remove_section_mapping(unsigned long start, unsigned long end)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 29d4dde..278ec8e 100644 (file)
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -123,7 +123,8 @@ int arch_add_memory(int nid, u64 start, u64 size)
        pgdata = NODE_DATA(nid);
 
        start = (unsigned long)__va(start);
-       create_section_mapping(start, start + size);
+       if (create_section_mapping(start, start + size))
+               return -EINVAL;
 
        /* this should work for most non-highmem platforms */
        zone = pgdata->node_zones;