This is a note to let you know that I've just added the patch titled x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-mpx-correctly-report-do_mpx_bt_fault-failures-to-user-space.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 5ed386ec09a5d75bcf073967e55e895c2607a5c3 Mon Sep 17 00:00:00 2001 From: Joerg Roedel <jroedel@xxxxxxx> Date: Thu, 6 Apr 2017 16:19:22 +0200 Subject: x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space From: Joerg Roedel <jroedel@xxxxxxx> commit 5ed386ec09a5d75bcf073967e55e895c2607a5c3 upstream. When this function fails it just sends a SIGSEGV signal to user-space using force_sig(). This signal is missing essential information about the cause, e.g. the trap_nr or an error code. Fix this by propagating the error to the only caller of mpx_handle_bd_fault(), do_bounds(), which sends the correct SIGSEGV signal to the process. Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Fixes: fe3d197f84319 ('x86, mpx: On-demand kernel allocation of bounds tables') Link: http://lkml.kernel.org/r/1491488362-27198-1-git-send-email-joro@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/mm/mpx.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -525,15 +525,7 @@ int mpx_handle_bd_fault(void) if (!kernel_managing_mpx_tables(current->mm)) return -EINVAL; - if (do_mpx_bt_fault()) { - force_sig(SIGSEGV, current); - /* - * The force_sig() is essentially "handling" this - * exception, so we do not pass up the error - * from do_mpx_bt_fault(). - */ - } - return 0; + return do_mpx_bt_fault(); } /* Patches currently in stable-queue which might be from jroedel@xxxxxxx are queue-4.4/x86-mpx-correctly-report-do_mpx_bt_fault-failures-to-user-space.patch