Subject: [folded-merged] mm-introduce-do_shared_fault-and-drop-do_fault-fix.patch removed from -mm tree
To: lliubbo@xxxxxxxxx,ak@xxxxxxxxxxxxxxx,bob.liu@xxxxxxxxxx,dave.hansen@xxxxxxxxxxxxxxx,kirill.shutemov@xxxxxxxxxxxxxxx,matthew.r.wilcox@xxxxxxxxx,mgorman@xxxxxxx,n-horiguchi@xxxxxxxxxxxxx,riel@xxxxxxxxxx,sasha.levin@xxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 03 Apr 2014 14:07:30 -0700
The patch titled
Subject: mm: do_shared_fault: fix potential NULL pointer dereference
has been removed from the -mm tree. Its filename was
mm-introduce-do_shared_fault-and-drop-do_fault-fix.patch
This patch was dropped because it was folded into mm-introduce-do_shared_fault-and-drop-do_fault.patch
------------------------------------------------------
From: Bob Liu <lliubbo@xxxxxxxxx>
Subject: mm: do_shared_fault: fix potential NULL pointer dereference
[ 232.869443] BUG: unable to handle kernel NULL pointer dereference at
0000000000000020
[ 232.870230] IP: [<mm/page-writeback.c:1612>]
balance_dirty_pages_ratelimited+0x1e/0x150
[ 232.870230] PGD 586e1d067 PUD 586e1e067 PMD 0
[ 232.870230] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 232.870230] Dumping ftrace buffer:
[ 232.870230] (ftrace buffer empty)
[ 232.870230] Modules linked in:
[ 232.870230] CPU: 36 PID: 9707 Comm: trinity-c36 Tainted: G W
3.14.0-rc4-next-20140225-sasha-00010-ga117461 #42
[ 232.870230] task: ffff880586dfb000 ti: ffff880586e34000 task.ti:
ffff880586e34000
[ 232.870230] RIP: 0010:[<mm/page-writeback.c:1612>]
[<mm/page-writeback.c:1612>]
balance_dirty_pages_ratelimited+0x1e/0x150
[ 232.870230] RSP: 0000:ffff880586e35c58 EFLAGS: 00010282
[ 232.870230] RAX: 0000000000000000 RBX: ffff880582831361 RCX:
0000000000000007
[ 232.870230] RDX: 0000000000000007 RSI: ffff880586dfbcc0 RDI:
ffff880582831361
[ 232.870230] RBP: ffff880586e35c78 R08: 0000000000000000 R09:
0000000000000000
[ 232.870230] R10: 0000000000000001 R11: 0000000000000001 R12:
00007f58007ee000
[ 232.870230] R13: ffff880c8d6d4f70 R14: 0000000000000200 R15:
ffff880c8dcce710
[ 232.870230] FS: 00007f58018bb700(0000) GS:ffff880c8e800000(0000)
knlGS:0000000000000000
[ 232.870230] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 232.870230] CR2: 0000000000000020 CR3: 0000000586e1c000 CR4:
00000000000006e0
[ 232.870230] Stack:
[ 232.870230] ffff880586e35c78 ffff880586e33400 00007f58007ee000
ffff880c8d6d4f70
[ 232.870230] ffff880586e35cd8 ffffffff8127d241 0000000000000001
0000000000000001
[ 232.870230] 0000000000000000 ffffea0032337080 0000000080000000
ffff880586e33400
[ 232.870230] Call Trace:
[ 232.870230] [<mm/memory.c:3467>] do_shared_fault+0x1a1/0x1f0
[ 232.870230] [<mm/memory.c:3487>] handle_pte_fault+0xc8/0x230
[ 232.870230] [<arch/x86/include/asm/preempt.h:98>] ? delay_tsc+0xea/0x110
[ 232.870230] [<mm/memory.c:3770>] __handle_mm_fault+0x36e/0x3a0
[ 232.870230] [<include/linux/rcupdate.h:829>] ? rcu_read_unlock+0x5d/0x60
[ 232.870230] [<include/linux/memcontrol.h:148>] handle_mm_fault+0x10b/0x1b0
[ 232.870230] [<arch/x86/mm/fault.c:1147>] ? __do_page_fault+0x2e2/0x590
[ 232.870230] [<arch/x86/mm/fault.c:1214>] __do_page_fault+0x551/0x590
[ 232.870230] [<kernel/sched/cputime.c:681>] ? vtime_account_user+0x91/0xa0
[ 232.870230] [<arch/x86/include/asm/atomic.h:26>] ?
context_tracking_user_exit+0xa8/0x1c0
[ 232.870230] [<arch/x86/include/asm/preempt.h:98>] ?
_raw_spin_unlock+0x30/0x50
[ 232.870230] [<kernel/sched/cputime.c:681>] ? vtime_account_user+0x91/0xa0
[ 232.870230] [<arch/x86/include/asm/atomic.h:26>] ?
context_tracking_user_exit+0xa8/0x1c0
[ 232.870230] [<arch/x86/include/asm/atomic.h:26>] do_page_fault+0x3d/0x70
[ 232.870230] [<arch/x86/kernel/kvm.c:263>] do_async_page_fault+0x35/0x100
[ 232.870230] [<arch/x86/kernel/entry_64.S:1496>] async_page_fault+0x28/0x30
[ 232.870230] Code: 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 48 83
ec 20 48 89 5d e8 4c
89 65 f0 4c 89 6d f8 48 89 fb 48 8b 87 50 01 00 00 <f6> 40 20 01 0f 85 18 01
00 00 65 48 8b 14 25 40
da 00 00 44 8b
[ 232.870230] RIP [<mm/page-writeback.c:1612>]
balance_dirty_pages_ratelimited+0x1e/0x150
[ 232.870230] RSP <ffff880586e35c58>
[ 232.870230] CR2: 0000000000000020
See: https://lkml.org/lkml/2014/2/25/463
This bug was first introduced by commit: 'mm: introduce do_shared_fault()
and drop do_fault()'(3a379a672c7adf40) The root cause is
'fault_page->mapping' might be set to NULL just after the if condition and
pass down to 'balance_dirty_pages_ratelimited()'. This patch fix this
issue by use a local variable just as before.
Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx>
Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff -puN mm/memory.c~mm-introduce-do_shared_fault-and-drop-do_fault-fix mm/memory.c
--- a/mm/memory.c~mm-introduce-do_shared_fault-and-drop-do_fault-fix
+++ a/mm/memory.c
@@ -3415,6 +3415,7 @@ static int do_shared_fault(struct mm_str
pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
{
struct page *fault_page;
+ struct address_space *mapping;
spinlock_t *ptl;
pte_t entry, *pte;
int dirtied = 0;
@@ -3475,13 +3476,14 @@ set_pte:
if (set_page_dirty(fault_page))
dirtied = 1;
+ mapping = fault_page->mapping;
unlock_page(fault_page);
- if ((dirtied || vma->vm_ops->page_mkwrite) && fault_page->mapping) {
+ if ((dirtied || vma->vm_ops->page_mkwrite) && mapping) {
/*
* Some device drivers do not set page.mapping but still
* dirty their pages
*/
- balance_dirty_pages_ratelimited(fault_page->mapping);
+ balance_dirty_pages_ratelimited(mapping);
}
/* file_update_time outside page_lock */
_
Patches currently in -mm which might be from lliubbo@xxxxxxxxx are
mm-introduce-do_shared_fault-and-drop-do_fault.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
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