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FAILED: patch "[PATCH] s390/mm: fix BUG_ON in crst_table_upgrade" failed to apply to 4.12-stable tree

PATCH [email protected] 2 participants 3 messages Sep 4, 2017 – Sep 7, 2017

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#0 lore raw

The patch below does not apply to the 4.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 8ab867cb0806a8e195de161fd8883a0578d1d050 Mon Sep 17 00:00:00 2001

From: Martin Schwidefsky <[email protected]>
Date: Thu, 31 Aug 2017 13:18:22 +0200
Subject: [PATCH] s390/mm: fix BUG_ON in crst_table_upgrade

A 31-bit compat process can force a BUG_ON in crst_table_upgrade with specific, invalid mmap calls, e.g.

mmap((void*) 0x7fff8000, 0x10000, 3, 32, -1, 0)

The arch_get_unmapped_area[_topdown] functions miss an if condition in the decision to do a page table upgrade.

Fixes 9b11c7912d00 ("s390/mm: simplify arch_get_unmapped_area[_topdown]")
Cc <[email protected]> # v4.12+
arch/s390/mm/mmap.c +4 -2
index 2e10d2b8ad35..5bea139517a2 100644
@@ -119,7 +119,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		return addr;
 
 check_asce_limit:
-	if (addr + len > current->mm->context.asce_limit) {
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
 		rc = crst_table_upgrade(mm, addr + len);
 		if (rc)
 			return (unsigned long) rc;
@@ -183,7 +184,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	}
 
 check_asce_limit:
-	if (addr + len > current->mm->context.asce_limit) {
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
 		rc = crst_table_upgrade(mm, addr + len);
 		if (rc)
 			return (unsigned long) rc;
#1 lore raw
Quoted 4 lines · On Mon, 04 Sep 2017 12:39:21 +0200 <[email protected]> wrote:

The patch below does not apply to the 4.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

The patch context looks a bit different in 4.12. Fixed with this version of the patch:
--

Quoted 1 line

From 66aa7812d5bc7a3488d75969067cfdae288c57fe Mon Sep 17 00:00:00 2001

From: Martin Schwidefsky <[email protected]>
Date: Thu, 31 Aug 2017 13:18:22 +0200
Subject: [PATCH] s390/mm: fix BUG_ON in crst_table_upgrade

commit 8ab867cb0806a8e195de161fd8883a0578d1d050 upstream.

A 31-bit compat process can force a BUG_ON in crst_table_upgrade with specific, invalid mmap calls, e.g.

mmap((void*) 0x7fff8000, 0x10000, 3, 32, -1, 0)

The arch_get_unmapped_area[_topdown] functions miss an if condition in the decision to do a page table upgrade.

[ms: Backport to 4.12, minor context change]

Fixes 9b11c7912d00 ("s390/mm: simplify arch_get_unmapped_area[_topdown]")
Cc <[email protected]> # v4.12+
---
 arch/s390/mm/mmap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
arch/s390/mm/mmap.c +4 -2
index b854b1da281a..888bee99fe64 100644
@@ -119,7 +119,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		return addr;
 
 check_asce_limit:
-	if (addr + len > current->mm->context.asce_limit) {
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
 		rc = crst_table_upgrade(mm);
 		if (rc)
 			return (unsigned long) rc;
@@ -183,7 +184,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	}
 
 check_asce_limit:
-	if (addr + len > current->mm->context.asce_limit) {
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
 		rc = crst_table_upgrade(mm);
 		if (rc)
 			return (unsigned long) rc;
Signature · 1 line
2.13.5
author maintainer
#2 lore raw
Quoted 10 lines · Martin Schwidefsky
Quoted 4 lines · On Mon, 04 Sep 2017 12:39:21 +0200 <[email protected]> wrote:

The patch below does not apply to the 4.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

The patch context looks a bit different in 4.12. Fixed with this version of the patch:

Thanks, that worked.

greg k-h