3.19.8-ckt12 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Dave Hansen <dave.han...@linux.intel.com> commit a1149fc83a1f97612e72ec24a0bdbabff7b85e77 upstream. 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> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Dave Hansen <d...@sr71.net> Cc: H. Peter Anvin <h...@zytor.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/r/20150607183704.3d69d...@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mi...@kernel.org> [ kamal: 3.19-stable prereq for "46561c3 x86/mpx: Do proper get_user() when running 32-bit binaries on 64-bit kernels" ] Signed-off-by: Kamal Mostafa <ka...@canonical.com> --- arch/x86/mm/mpx.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index 4d1c11c..9c208e4 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -409,6 +409,7 @@ static int allocate_bt(long __user *bd_entry) unsigned long expected_old_val = 0; unsigned long actual_old_val = 0; unsigned long bt_addr; + unsigned long bd_new_entry; int ret = 0; /* @@ -421,7 +422,7 @@ static int allocate_bt(long __user *bd_entry) /* * 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 @@ -435,7 +436,7 @@ static int allocate_bt(long __user *bd_entry) * 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; @@ -465,7 +466,7 @@ static int allocate_bt(long __user *bd_entry) } 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; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
