1. Patchew
  2. linux
  3. [PATCH -next 0/6] Fix two issue about ext4 extended attribute
  4. View patch

[PATCH -next 1/6] ext4: fix WARNING in ext4_expand_extra_isize_ea

Ye Bin posted 6 patches 2 years, 9 months ago
There is a newer version of this series
[PATCH -next 1/6] ext4: fix WARNING in ext4_expand_extra_isize_ea
Posted by Ye Bin 2 years, 9 months ago 
From: Ye Bin <yebin10@huawei.com>

Syzbot found the following issue:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3631 at mm/page_alloc.c:5534 __alloc_pages+0x30a/0x560 mm/page_alloc.c:5534
Modules linked in:
CPU: 1 PID: 3631 Comm: syz-executor261 Not tainted 6.1.0-rc6-syzkaller-00308-g644e9524388a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:__alloc_pages+0x30a/0x560 mm/page_alloc.c:5534
RSP: 0018:ffffc90003ccf080 EFLAGS: 00010246
RAX: ffffc90003ccf0e0 RBX: 000000000000000c RCX: 0000000000000000
RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90003ccf108
RBP: ffffc90003ccf198 R08: dffffc0000000000 R09: ffffc90003ccf0e0
R10: fffff52000799e21 R11: 1ffff92000799e1c R12: 0000000000040c40
R13: 1ffff92000799e18 R14: dffffc0000000000 R15: 1ffff92000799e14
FS:  0000555555c10300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc36f70000 CR3: 00000000744ad000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __alloc_pages_node include/linux/gfp.h:223 [inline]
 alloc_pages_node include/linux/gfp.h:246 [inline]
 __kmalloc_large_node+0x8a/0x1a0 mm/slab_common.c:1096
 __do_kmalloc_node mm/slab_common.c:943 [inline]
 __kmalloc+0xfe/0x1a0 mm/slab_common.c:968
 kmalloc include/linux/slab.h:558 [inline]
 ext4_xattr_move_to_block fs/ext4/xattr.c:2558 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2673 [inline]
 ext4_expand_extra_isize_ea+0xe3f/0x1cd0 fs/ext4/xattr.c:2765
 __ext4_expand_extra_isize+0x2b8/0x3f0 fs/ext4/inode.c:5857
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5900 [inline]
 __ext4_mark_inode_dirty+0x51a/0x670 fs/ext4/inode.c:5978
 ext4_inline_data_truncate+0x548/0xd00 fs/ext4/inline.c:2021
 ext4_truncate+0x341/0xeb0 fs/ext4/inode.c:4221
 ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339
 ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5515 [inline]
 ext4_fill_super+0x80ed/0x8610 fs/ext4/super.c:5643
 get_tree_bdev+0x400/0x620 fs/super.c:1324
 vfs_get_tree+0x88/0x270 fs/super.c:1531
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
 </TASK>

Reason is allocate 16M memory by kmalloc, but MAX_ORDER is 11, kmalloc
can allocate maxium size memory is 4M.
XATTR_SIZE_MAX is currently 64k, but EXT4_XATTR_SIZE_MAX is '(1 << 24)',
so 'ext4_xattr_check_entries()' regards this length as legal. Then trigger
warning in 'ext4_xattr_move_to_block()'.
To solve above issue, according to Jan Kara's suggestion use kvmalloc()
to allocate memory in ext4_xattr_move_to_block().

Reported-by: syzbot+4d99a966fd74bdeeec36@syzkaller.appspotmail.com
Fixes: 54dd0e0a1b25 ("ext4: add extra checks to ext4_xattr_block_get()")
Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 fs/ext4/xattr.h | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index 824faf0b15a8..444ee46838c3 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -71,15 +71,10 @@ struct ext4_xattr_entry {
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
 /*
- * XATTR_SIZE_MAX is currently 64k, but for the purposes of checking
- * for file system consistency errors, we use a somewhat bigger value.
- * This allows XATTR_SIZE_MAX to grow in the future, but by using this
- * instead of INT_MAX for certain consistency checks, we don't need to
- * worry about arithmetic overflows.  (Actually XATTR_SIZE_MAX is
- * defined in include/uapi/linux/limits.h, so changing it is going
- * not going to be trivial....)
+ * Use XATTR_SIZE_MAX to checking for file system consistency errors. Extended
+ * attribute length exceed XATTR_SIZE_MAX is ilegal.
  */
-#define EXT4_XATTR_SIZE_MAX (1 << 24)
+#define EXT4_XATTR_SIZE_MAX XATTR_SIZE_MAX
 
 /*
  * The minimum size of EA value when you start storing it in an external inode
-- 
2.31.1
Re: [PATCH -next 1/6] ext4: fix WARNING in ext4_expand_extra_isize_ea
Posted by Jan Kara 2 years, 9 months ago 
On Tue 06-12-22 09:58:01, Ye Bin wrote:
> From: Ye Bin <yebin10@huawei.com>
> 
> Syzbot found the following issue:
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 3631 at mm/page_alloc.c:5534 __alloc_pages+0x30a/0x560 mm/page_alloc.c:5534
> Modules linked in:
> CPU: 1 PID: 3631 Comm: syz-executor261 Not tainted 6.1.0-rc6-syzkaller-00308-g644e9524388a #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
> RIP: 0010:__alloc_pages+0x30a/0x560 mm/page_alloc.c:5534
> RSP: 0018:ffffc90003ccf080 EFLAGS: 00010246
> RAX: ffffc90003ccf0e0 RBX: 000000000000000c RCX: 0000000000000000
> RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90003ccf108
> RBP: ffffc90003ccf198 R08: dffffc0000000000 R09: ffffc90003ccf0e0
> R10: fffff52000799e21 R11: 1ffff92000799e1c R12: 0000000000040c40
> R13: 1ffff92000799e18 R14: dffffc0000000000 R15: 1ffff92000799e14
> FS:  0000555555c10300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007ffc36f70000 CR3: 00000000744ad000 CR4: 00000000003506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  __alloc_pages_node include/linux/gfp.h:223 [inline]
>  alloc_pages_node include/linux/gfp.h:246 [inline]
>  __kmalloc_large_node+0x8a/0x1a0 mm/slab_common.c:1096
>  __do_kmalloc_node mm/slab_common.c:943 [inline]
>  __kmalloc+0xfe/0x1a0 mm/slab_common.c:968
>  kmalloc include/linux/slab.h:558 [inline]
>  ext4_xattr_move_to_block fs/ext4/xattr.c:2558 [inline]
>  ext4_xattr_make_inode_space fs/ext4/xattr.c:2673 [inline]
>  ext4_expand_extra_isize_ea+0xe3f/0x1cd0 fs/ext4/xattr.c:2765
>  __ext4_expand_extra_isize+0x2b8/0x3f0 fs/ext4/inode.c:5857
>  ext4_try_to_expand_extra_isize fs/ext4/inode.c:5900 [inline]
>  __ext4_mark_inode_dirty+0x51a/0x670 fs/ext4/inode.c:5978
>  ext4_inline_data_truncate+0x548/0xd00 fs/ext4/inline.c:2021
>  ext4_truncate+0x341/0xeb0 fs/ext4/inode.c:4221
>  ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339
>  ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474
>  __ext4_fill_super fs/ext4/super.c:5515 [inline]
>  ext4_fill_super+0x80ed/0x8610 fs/ext4/super.c:5643
>  get_tree_bdev+0x400/0x620 fs/super.c:1324
>  vfs_get_tree+0x88/0x270 fs/super.c:1531
>  do_new_mount+0x289/0xad0 fs/namespace.c:3040
>  do_mount fs/namespace.c:3383 [inline]
>  __do_sys_mount fs/namespace.c:3591 [inline]
>  __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>  </TASK>
> 
> Reason is allocate 16M memory by kmalloc, but MAX_ORDER is 11, kmalloc
> can allocate maxium size memory is 4M.
> XATTR_SIZE_MAX is currently 64k, but EXT4_XATTR_SIZE_MAX is '(1 << 24)',
> so 'ext4_xattr_check_entries()' regards this length as legal. Then trigger
> warning in 'ext4_xattr_move_to_block()'.
> To solve above issue, according to Jan Kara's suggestion use kvmalloc()
> to allocate memory in ext4_xattr_move_to_block().
> 
> Reported-by: syzbot+4d99a966fd74bdeeec36@syzkaller.appspotmail.com
> Fixes: 54dd0e0a1b25 ("ext4: add extra checks to ext4_xattr_block_get()")
> Signed-off-by: Ye Bin <yebin10@huawei.com>

The changelog speak about kvmalloc() while your patch changes
EXT4_XATTR_SIZE_MAX. This needs to be fixed. If Ted is find with this
change, I have no problem with it either but I remember there were some
discussions about what EXT4_XATTR_SIZE_MAX should be when ea_inode feature
has been developed. Ted might remember.

Also the change from kmalloc() to kvmalloc() is a desirable one anyway. It
is not always easy to find physically contiguous 64k of memory so
kvmalloc() makes the allocation much more likely to succeed.

								Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR
Re: [PATCH -next 1/6] ext4: fix WARNING in ext4_expand_extra_isize_ea
Posted by yebin (H) 2 years, 9 months ago 

On 2022/12/6 20:04, Jan Kara wrote:
> On Tue 06-12-22 09:58:01, Ye Bin wrote:
>> From: Ye Bin <yebin10@huawei.com>
>>
>> Syzbot found the following issue:
>> ------------[ cut here ]------------
>> WARNING: CPU: 1 PID: 3631 at mm/page_alloc.c:5534 __alloc_pages+0x30a/0x560 mm/page_alloc.c:5534
>> Modules linked in:
>> CPU: 1 PID: 3631 Comm: syz-executor261 Not tainted 6.1.0-rc6-syzkaller-00308-g644e9524388a #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
>> RIP: 0010:__alloc_pages+0x30a/0x560 mm/page_alloc.c:5534
>> RSP: 0018:ffffc90003ccf080 EFLAGS: 00010246
>> RAX: ffffc90003ccf0e0 RBX: 000000000000000c RCX: 0000000000000000
>> RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90003ccf108
>> RBP: ffffc90003ccf198 R08: dffffc0000000000 R09: ffffc90003ccf0e0
>> R10: fffff52000799e21 R11: 1ffff92000799e1c R12: 0000000000040c40
>> R13: 1ffff92000799e18 R14: dffffc0000000000 R15: 1ffff92000799e14
>> FS:  0000555555c10300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007ffc36f70000 CR3: 00000000744ad000 CR4: 00000000003506e0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>>   <TASK>
>>   __alloc_pages_node include/linux/gfp.h:223 [inline]
>>   alloc_pages_node include/linux/gfp.h:246 [inline]
>>   __kmalloc_large_node+0x8a/0x1a0 mm/slab_common.c:1096
>>   __do_kmalloc_node mm/slab_common.c:943 [inline]
>>   __kmalloc+0xfe/0x1a0 mm/slab_common.c:968
>>   kmalloc include/linux/slab.h:558 [inline]
>>   ext4_xattr_move_to_block fs/ext4/xattr.c:2558 [inline]
>>   ext4_xattr_make_inode_space fs/ext4/xattr.c:2673 [inline]
>>   ext4_expand_extra_isize_ea+0xe3f/0x1cd0 fs/ext4/xattr.c:2765
>>   __ext4_expand_extra_isize+0x2b8/0x3f0 fs/ext4/inode.c:5857
>>   ext4_try_to_expand_extra_isize fs/ext4/inode.c:5900 [inline]
>>   __ext4_mark_inode_dirty+0x51a/0x670 fs/ext4/inode.c:5978
>>   ext4_inline_data_truncate+0x548/0xd00 fs/ext4/inline.c:2021
>>   ext4_truncate+0x341/0xeb0 fs/ext4/inode.c:4221
>>   ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339
>>   ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474
>>   __ext4_fill_super fs/ext4/super.c:5515 [inline]
>>   ext4_fill_super+0x80ed/0x8610 fs/ext4/super.c:5643
>>   get_tree_bdev+0x400/0x620 fs/super.c:1324
>>   vfs_get_tree+0x88/0x270 fs/super.c:1531
>>   do_new_mount+0x289/0xad0 fs/namespace.c:3040
>>   do_mount fs/namespace.c:3383 [inline]
>>   __do_sys_mount fs/namespace.c:3591 [inline]
>>   __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568
>>   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>>   do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>>   entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>   </TASK>
>>
>> Reason is allocate 16M memory by kmalloc, but MAX_ORDER is 11, kmalloc
>> can allocate maxium size memory is 4M.
>> XATTR_SIZE_MAX is currently 64k, but EXT4_XATTR_SIZE_MAX is '(1 << 24)',
>> so 'ext4_xattr_check_entries()' regards this length as legal. Then trigger
>> warning in 'ext4_xattr_move_to_block()'.
>> To solve above issue, according to Jan Kara's suggestion use kvmalloc()
>> to allocate memory in ext4_xattr_move_to_block().
>>
>> Reported-by: syzbot+4d99a966fd74bdeeec36@syzkaller.appspotmail.com
>> Fixes: 54dd0e0a1b25 ("ext4: add extra checks to ext4_xattr_block_get()")
>> Signed-off-by: Ye Bin <yebin10@huawei.com>
> The changelog speak about kvmalloc() while your patch changes
> EXT4_XATTR_SIZE_MAX. This needs to be fixed. If Ted is find with this
> change, I have no problem with it either but I remember there were some
> discussions about what EXT4_XATTR_SIZE_MAX should be when ea_inode feature
> has been developed. Ted might remember.

I'm sorry I forgot to modify the commit message, I will modify the 
changelog again.

> Also the change from kmalloc() to kvmalloc() is a desirable one anyway. It
> is not always easy to find physically contiguous 64k of memory so
> kvmalloc() makes the allocation much more likely to succeed.
>
> 								Honza

A later patch use kvmalloc to allocate  extended attribute value memory.

Patchew 2.1-devel-b67e4c2

© 2016 - 2025 Red Hat, Inc.