From 9e2760d18b3cf179534bbc27692c84879c61b97c Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Sat, 28 Jul 2012 00:20:34 +0200 Subject: [PATCH] m68k: Make sys_atomic_cmpxchg_32 work on classic m68k User space access must always go through uaccess accessors, since on classic m68k user space and kernel space are completely separate. Signed-off-by: Andreas Schwab Tested-by: Thorsten Glaser Signed-off-by: Geert Uytterhoeven Cc: stable@vger.kernel.org --- arch/m68k/kernel/sys_m68k.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c index 8623f8dc16f8..9a5932ec3689 100644 --- a/arch/m68k/kernel/sys_m68k.c +++ b/arch/m68k/kernel/sys_m68k.c @@ -479,9 +479,13 @@ sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5, goto bad_access; } - mem_value = *mem; + /* + * No need to check for EFAULT; we know that the page is + * present and writable. + */ + __get_user(mem_value, mem); if (mem_value == oldval) - *mem = newval; + __put_user(newval, mem); pte_unmap_unlock(pte, ptl); up_read(&mm->mmap_sem); -- 2.34.1