Re: [PATCH] jfs: fix shift-out-of-bounds in dbJoin

Dave Kleikamp
2024-01-29T14:39:41Z

On 1/28/24 2:49PM, Matthew Wilcox wrote:
> On Wed, Oct 11, 2023 at 08:09:37PM +0530, Manas Ghandat wrote:
>> Currently while joining the leaf in a buddy system there is shift out
>> of bound error in calculation of BUDSIZE. Added the required check
>> to the BUDSIZE and fixed the documentation as well.
>
> This patch causes xfstests to fail frequently. The one this trace is
> from was generic/074.

Thanks for catching this. The sanity test is not right, so we need to
revert that one.

Shaggy

>
> Sasha, I see this one was AUTOSEL. Please stop it from going into
> -stable.
>
> 00274 [failed, exit status 1]------------[ cut here ]------------
> 00274 kernel BUG at fs/jfs/inode.c:169!
> 00274 invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
> 00274 CPU: 7 PID: 52174 Comm: umount Kdump: loaded Tainted: G N 6.7.0-rc2-00020-gcca974daeb6c #442
> 00274 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> 00274 RIP: 0010:jfs_evict_inode+0xfb/0x110
> 00274 Code: 28 fc ff ff a8 04 75 24 4d 85 e4 74 10 49 83 7c 24 80 00 74 08 48 89 df e8 e2 a5 00 00 48 89 df e8 3a 95 ee ff e9 2f ff ff ff <0f> 0b 48 89 df e8 0b 28 00 00 eb d2 66 0f 1f 84 00 00 00 00 00 90
> 00274 RSP: 0018:ffff8880080bbd48 EFLAGS: 00010287
> 00274 RAX: ffff88804b209a80 RBX: ffff88804b209df8 RCX: 0000000000000000
> 00274 RDX: ffff88800b813ce0 RSI: ffffffff8217a259 RDI: ffff88804b209df8
> 00274 RBP: ffff8880080bbd58 R08: 0000000000000001 R09: 0000000000000001
> 00274 R10: ffff8880551e4540 R11: 0000000000000001 R12: ffff88804b209fa8
> 00274 R13: ffffffff81e35fa0 R14: ffff88800eaae7d0 R15: ffff88800eaae7d0
> 00274 FS: 00007f4f5784a840(0000) GS:ffff88807d9c0000(0000) knlGS:0000000000000000
> 00274 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> 00274 CR2: 00007f4f57ae2c00 CR3: 000000000a5c4005 CR4: 0000000000770eb0
> 00274 PKRU: 55555554
> 00274 Call Trace:
> 00274 <TASK>
> 00274 ? show_regs+0x60/0x70
> 00274 ? die+0x32/0x90
> 00274 ? do_trap+0xbf/0xe0
> 00274 ? do_error_trap+0x75/0x110
> 00274 ? jfs_evict_inode+0xfb/0x110
> 00274 ? exc_invalid_op+0x52/0x70
> 00274 ? jfs_evict_inode+0xfb/0x110
> 00274 ? asm_exc_invalid_op+0x1b/0x20
> 00274 ? jfs_evict_inode+0xfb/0x110
> 00274 ? jfs_evict_inode+0x3a/0x110
> 00274 evict+0xcc/0x1d0
> 00274 dispose_list+0x48/0x80
> 00274 evict_inodes+0x14c/0x190
> 00274 generic_shutdown_super+0x34/0x160
> 00274 kill_block_super+0x16/0x40
> 00274 deactivate_locked_super+0x2d/0xa0
> 00274 deactivate_super+0x3b/0x50
> 00274 cleanup_mnt+0xbe/0x160
> 00274 __cleanup_mnt+0xd/0x20
> 00274 task_work_run+0x59/0xa0
> 00274 exit_to_user_mode_prepare+0x175/0x180
> 00274 syscall_exit_to_user_mode+0x1d/0x50
> 00274 do_syscall_64+0x4e/0xf0
> 00274 entry_SYSCALL_64_after_hwframe+0x6e/0x76
> 00274 RIP: 0033:0x7f4f57a76857
> 00274 Code: af 95 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 79 95 0c 00 f7 d8 64 89 02 b8
> 00274 RSP: 002b:00007fff75aa4be8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
> 00274 RAX: 0000000000000000 RBX: 00005586b9c30ad8 RCX: 00007f4f57a76857
> 00274 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005586b9c343e0
> 00274 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000073
> 00274 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4f57bb1264
> 00274 R13: 00005586b9c343e0 R14: 00005586b9c30bf0 R15: 00005586b9c309c0
> 00274 </TASK>
> 00274 Modules linked in:
>
> I haven't attempted to dig into why yet.
>
>> Reported-by: syzbot+411debe54d318eaed386@syzkaller.appspotmail.com
>> Closes: https://syzkaller.appspot.com/bug?extid=411debe54d318eaed386
>> Signed-off-by: Manas Ghandat <ghandatmanas@gmail.com>
>> ---
>> fs/jfs/jfs_dmap.c | 8 +++++++-
>> 1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
>> index 6b838d3ae7c2..baa97bda1c7a 100644
>> --- a/fs/jfs/jfs_dmap.c
>> +++ b/fs/jfs/jfs_dmap.c
>> @@ -2730,7 +2730,9 @@ static int dbBackSplit(dmtree_t * tp, int leafno)
>> * leafno - the number of the leaf to be updated.
>> * newval - the new value for the leaf.
>> *
>> - * RETURN VALUES: none
>> + * RETURN VALUES:
>> + * 0 - success
>> + * -EIO - i/o error
>> */
>> static int dbJoin(dmtree_t * tp, int leafno, int newval)
>> {
>> @@ -2757,6 +2759,10 @@ static int dbJoin(dmtree_t * tp, int leafno, int newval)
>> * get the buddy size (number of words covered) of
>> * the new value.
>> */
>> +
>> + if ((newval - tp->dmt_budmin) > BUDMIN)
>> + return -EIO;
>> +
>> budsz = BUDSIZE(newval, tp->dmt_budmin);
>>
>> /* try to join.
>> --
>> 2.37.2
>>