* [PATCH 6.1.y] mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM
@ 2025-01-11 14:15 alvalan9
2025-01-11 19:04 ` Sasha Levin
2025-01-12 10:09 ` Greg KH
0 siblings, 2 replies; 3+ messages in thread
From: alvalan9 @ 2025-01-11 14:15 UTC (permalink / raw)
To: stable, david; +Cc: alvalan9, Liam.Howlett, cl, akpm
From: David Hildenbrand <david@redhat.com>
[ Upstream commit 091c1dd2d4df6edd1beebe0e5863d4034ade9572 ]
We currently assume that there is at least one VMA in a MM, which isn't
true.
So we might end up having find_vma() return NULL, to then de-reference
NULL. So properly handle find_vma() returning NULL.
This fixes the report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 6021 Comm: syz-executor284 Not tainted 6.12.0-rc7-syzkaller-00187-gf868cd251776 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline]
RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194
Code: ...
RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000
RDX: ffff88807e171300 RSI: dffffc0000000000 RDI: ffff88803390c044
RBP: ffff88807e171428 R08: 0000000000000014 R09: fffffbfff2039ef1
R10: ffffffff901cf78f R11: 0000000000000000 R12: 0000000000000003
R13: ffffc9000375fe90 R14: ffffc9000375fe98 R15: ffffc9000375fdf8
FS: 00005555919e1380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555919e1ca8 CR3: 000000007f12a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
kernel_migrate_pages+0x5b2/0x750 mm/mempolicy.c:1709
__do_sys_migrate_pages mm/mempolicy.c:1727 [inline]
__se_sys_migrate_pages mm/mempolicy.c:1723 [inline]
__x64_sys_migrate_pages+0x96/0x100 mm/mempolicy.c:1723
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
[akpm@linux-foundation.org: add unlikely()]
Link: https://lkml.kernel.org/r/20241120201151.9518-1-david@redhat.com
Fixes: 39743889aaf7 ("[PATCH] Swap Migration V5: sys_migrate_pages interface")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: syzbot+3511625422f7aa637f0d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/673d2696.050a0220.3c9d61.012f.GAE@google.com/T/
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Remove mmap_read_unlock() because mmap_read_lock() is not called before find_vma() ]
Signed-off-by: Alva Lan <alvalan9@foxmail.com>
---
mm/mempolicy.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 399d8cb48813..d67dd0f503fa 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1068,6 +1068,9 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest,
* space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
*/
vma = find_vma(mm, 0);
+ if (unlikely(!vma)) {
+ return 0;
+ }
VM_BUG_ON(!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)));
queue_pages_range(mm, vma->vm_start, mm->task_size, &nmask,
flags | MPOL_MF_DISCONTIG_OK, &pagelist);
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 6.1.y] mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM
2025-01-11 14:15 [PATCH 6.1.y] mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM alvalan9
@ 2025-01-11 19:04 ` Sasha Levin
2025-01-12 10:09 ` Greg KH
1 sibling, 0 replies; 3+ messages in thread
From: Sasha Levin @ 2025-01-11 19:04 UTC (permalink / raw)
To: stable; +Cc: alvalan9, Sasha Levin
[ Sasha's backport helper bot ]
Hi,
The upstream commit SHA1 provided is correct: 091c1dd2d4df6edd1beebe0e5863d4034ade9572
WARNING: Author mismatch between patch and upstream commit:
Backport author: alvalan9@foxmail.com
Commit author: David Hildenbrand<david@redhat.com>
Status in newer kernel trees:
6.12.y | Present (different SHA1: 42d9fe2adf86)
6.6.y | Present (different SHA1: a13b2b9b0b0b)
6.1.y | Not found
Note: The patch differs from the upstream commit:
---
1: 091c1dd2d4df < -: ------------ mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM
-: ------------ > 1: 8c55d12358ee mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y | Success | Success |
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 6.1.y] mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM
2025-01-11 14:15 [PATCH 6.1.y] mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM alvalan9
2025-01-11 19:04 ` Sasha Levin
@ 2025-01-12 10:09 ` Greg KH
1 sibling, 0 replies; 3+ messages in thread
From: Greg KH @ 2025-01-12 10:09 UTC (permalink / raw)
To: alvalan9; +Cc: stable, david, Liam.Howlett, cl, akpm
On Sat, Jan 11, 2025 at 10:15:20PM +0800, alvalan9@foxmail.com wrote:
> From: David Hildenbrand <david@redhat.com>
>
> [ Upstream commit 091c1dd2d4df6edd1beebe0e5863d4034ade9572 ]
>
> We currently assume that there is at least one VMA in a MM, which isn't
> true.
>
> So we might end up having find_vma() return NULL, to then de-reference
> NULL. So properly handle find_vma() returning NULL.
>
> This fixes the report:
>
> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 1 UID: 0 PID: 6021 Comm: syz-executor284 Not tainted 6.12.0-rc7-syzkaller-00187-gf868cd251776 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
> RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline]
> RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194
> Code: ...
> RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000
> RDX: ffff88807e171300 RSI: dffffc0000000000 RDI: ffff88803390c044
> RBP: ffff88807e171428 R08: 0000000000000014 R09: fffffbfff2039ef1
> R10: ffffffff901cf78f R11: 0000000000000000 R12: 0000000000000003
> R13: ffffc9000375fe90 R14: ffffc9000375fe98 R15: ffffc9000375fdf8
> FS: 00005555919e1380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00005555919e1ca8 CR3: 000000007f12a000 CR4: 00000000003526f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> kernel_migrate_pages+0x5b2/0x750 mm/mempolicy.c:1709
> __do_sys_migrate_pages mm/mempolicy.c:1727 [inline]
> __se_sys_migrate_pages mm/mempolicy.c:1723 [inline]
> __x64_sys_migrate_pages+0x96/0x100 mm/mempolicy.c:1723
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> [akpm@linux-foundation.org: add unlikely()]
> Link: https://lkml.kernel.org/r/20241120201151.9518-1-david@redhat.com
> Fixes: 39743889aaf7 ("[PATCH] Swap Migration V5: sys_migrate_pages interface")
> Signed-off-by: David Hildenbrand <david@redhat.com>
> Reported-by: syzbot+3511625422f7aa637f0d@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/lkml/673d2696.050a0220.3c9d61.012f.GAE@google.com/T/
> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
> Reviewed-by: Christoph Lameter <cl@linux.com>
> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> [ Remove mmap_read_unlock() because mmap_read_lock() is not called before find_vma() ]
> Signed-off-by: Alva Lan <alvalan9@foxmail.com>
> ---
> mm/mempolicy.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 399d8cb48813..d67dd0f503fa 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1068,6 +1068,9 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest,
> * space range and MPOL_MF_DISCONTIG_OK, this call can not fail.
> */
> vma = find_vma(mm, 0);
> + if (unlikely(!vma)) {
> + return 0;
> + }
Please follow the proper kernel coding style when doing backports, you
have {} here where not needed, AND you have trailing whitespace :(
Also, I'd like for someone on the reviewed-by chain to review that this
backport actually is ok before applying it (after you fix it up...)
thanks,
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-01-11 14:15 [PATCH 6.1.y] mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM alvalan9
2025-01-11 19:04 ` Sasha Levin
2025-01-12 10:09 ` Greg KH
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