From: chen jie <chen jie@chenjie6@xxxxxxxxx> Subject: mm/memory.c: check return value of ioremap_prot ioremap_prot() can return NULL which could lead to an oops. Link: http://lkml.kernel.org/r/1533195441-58594-1-git-send-email-chenjie6@xxxxxxxxxx Signed-off-by: chen jie <chenjie6@xxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Li Zefan <lizefan@xxxxxxxxxx> Cc: chenjie <chenjie6@xxxxxxxxxx> Cc: Yang Shi <shy828301@xxxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/memory.c~mm-bugfix-check-return-value-of-ioremap_prot +++ a/mm/memory.c @@ -4395,6 +4395,9 @@ int generic_access_phys(struct vm_area_s return -EINVAL; maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); + if (!maddr) + return -ENOMEM; + if (write) memcpy_toio(maddr + offset, buf, len); else _
