Commit a1194097 authored by Anton Blanchard's avatar Anton Blanchard Committed by Benjamin Herrenschmidt
Browse files

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



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: default avatarAnton Blanchard <anton@samba.org>
Cc: stable@kernel.org
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent dfbe93a2

arch/powerpc/include/asm/sparsemem.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/mm/hash_utils_64.c

+3 −3
Original line number Diff line number Diff line
@@ -531,11 +531,11 @@ 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)

arch/powerpc/mm/mem.c

+2 −1
Original line number Diff line number Diff line
@@ -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;

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