From: Dave Hansen <dave.han...@linux.intel.com> When we allocate a bounds table, we call mmap(), then add a "valid" bit to the value before storing it in to the bounds directory.
If we fail along the way, we go and mask that valid bit _back_ out. That seems a little silly, and this makes it much more clear when we have a plain address versus an actual table _entry_. Signed-off-by: Dave Hansen <dave.han...@linux.intel.com> Reviewed-by: Thomas Gleixner <t...@linutronix.de> --- b/arch/x86/mm/mpx.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff -puN arch/x86/mm/mpx.c~mpx-remove-unnecessary-masking arch/x86/mm/mpx.c --- a/arch/x86/mm/mpx.c~mpx-remove-unnecessary-masking 2015-05-27 09:32:19.588673255 -0700 +++ b/arch/x86/mm/mpx.c 2015-05-27 09:32:19.592673436 -0700 @@ -429,6 +429,7 @@ static int allocate_bt(long __user *bd_e unsigned long expected_old_val = 0; unsigned long actual_old_val = 0; unsigned long bt_addr; + unsigned long bd_new_entry; int ret = 0; /* @@ -441,7 +442,7 @@ static int allocate_bt(long __user *bd_e /* * Set the valid flag (kinda like _PAGE_PRESENT in a pte) */ - bt_addr = bt_addr | MPX_BD_ENTRY_VALID_FLAG; + bd_new_entry = bt_addr | MPX_BD_ENTRY_VALID_FLAG; /* * Go poke the address of the new bounds table in to the @@ -455,7 +456,7 @@ static int allocate_bt(long __user *bd_e * of the MPX code that have to pagefault_disable(). */ ret = user_atomic_cmpxchg_inatomic(&actual_old_val, bd_entry, - expected_old_val, bt_addr); + expected_old_val, bd_new_entry); if (ret) goto out_unmap; @@ -486,7 +487,7 @@ static int allocate_bt(long __user *bd_e trace_mpx_new_bounds_table(bt_addr); return 0; out_unmap: - vm_munmap(bt_addr & MPX_BT_ADDR_MASK, MPX_BT_SIZE_BYTES); + vm_munmap(bt_addr, MPX_BT_SIZE_BYTES); return ret; } _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/