This is a note to let you know that I've just added the patch titled
s390/mm: fix off-by-one bug in 5-level page table handling
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: s390-mm-fix-off-by-one-bug-in-5-level-page-table-handling.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 8d306f53b63099fec2d56300149e400d181ba4f5 Mon Sep 17 00:00:00 2001
From: Heiko Carstens heiko.carstens@de.ibm.com Date: Mon, 4 Dec 2017 09:42:45 +0100 Subject: s390/mm: fix off-by-one bug in 5-level page table handling
From: Heiko Carstens heiko.carstens@de.ibm.com
commit 8d306f53b63099fec2d56300149e400d181ba4f5 upstream.
Martin Cermak reported that setting a uprobe doesn't work. Reason for this is that the common uprobes code tries to get an unmapped area at the last possible page within an address space.
This broke with commit 1aea9b3f9210 ("s390/mm: implement 5 level pages tables") which introduced an off-by-one bug which prevents to map anything at the last possible page within an address space.
The check with the off-by-one bug however can be removed since with commit 8ab867cb0806 ("s390/mm: fix BUG_ON in crst_table_upgrade") the necessary check is done at both call sites.
Reported-by: Martin Cermak mcermak@redhat.com Bisected-by: Thomas Richter tmricht@linux.vnet.ibm.com Fixes: 1aea9b3f9210 ("s390/mm: implement 5 level pages tables") Reviewed-by: Hendrik Brueckner brueckner@linux.vnet.ibm.com Signed-off-by: Heiko Carstens heiko.carstens@de.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/mm/pgalloc.c | 2 -- 1 file changed, 2 deletions(-)
--- a/arch/s390/mm/pgalloc.c +++ b/arch/s390/mm/pgalloc.c @@ -85,8 +85,6 @@ int crst_table_upgrade(struct mm_struct
/* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */ VM_BUG_ON(mm->context.asce_limit < _REGION2_SIZE); - if (end >= TASK_SIZE_MAX) - return -ENOMEM; rc = 0; notify = 0; while (mm->context.asce_limit < end) {
Patches currently in stable-queue which might be from heiko.carstens@de.ibm.com are
queue-4.14/s390-always-save-and-restore-all-registers-on-context-switch.patch queue-4.14/s390-fix-compat-system-call-table.patch queue-4.14/s390-mm-fix-off-by-one-bug-in-5-level-page-table-handling.patch