btrfs: zoned: skip splitting and logical rewriting on pre-alloc write

In the Linux kernel, the following vulnerability has been resolved:

btrfs: zoned: skip splitting and logical rewriting on pre-alloc write

When doing a relocation, there is a chance that at the time of

btrfs_reloc_clone_csums(), there is no checksum for the corresponding

region.

In this case, btrfs_finish_ordered_zoned()'s sum points to an invalid item

and so ordered_extent's logical is set to some invalid value. Then,

btrfs_lookup_block_group() in btrfs_zone_finish_endio() failed to find a

block group and will hit an assert or a null pointer dereference as

following.

This can be reprodcued by running btrfs/028 several times (e.g, 4 to 16

times) with a null_blk setup. The device's zone size and capacity is set to

32 MB and the storage size is set to 5 GB on my setup.

KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]

CPU: 6 PID: 3105720 Comm: kworker/u16:13 Tainted: G W 6.5.0-rc6-kts+ #1

Hardware name: Supermicro Super Server/X10SRL-F, BIOS 2.0 12/17/2015

Workqueue: btrfs-endio-write btrfs_work_helper [btrfs]

RIP: 0010:btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs]

Code: 41 54 49 89 fc 55 48 89 f5 53 e8 57 7d fc ff 48 8d b8 88 00 00 00 48 89 c3 48 b8 00 00 00 00 00

> 3c 02 00 0f 85 02 01 00 00 f6 83 88 00 00 00 01 0f 84 a8 00 00

RSP: 0018:ffff88833cf87b08 EFLAGS: 00010206

RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000

RDX: 0000000000000011 RSI: 0000000000000004 RDI: 0000000000000088

RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed102877b827

R10: ffff888143bdc13b R11: ffff888125b1cbc0 R12: ffff888143bdc000

R13: 0000000000007000 R14: ffff888125b1cba8 R15: 0000000000000000

FS: 0000000000000000(0000) GS:ffff88881e500000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f3ed85223d5 CR3: 00000001519b4005 CR4: 00000000001706e0

Call Trace:

<TASK>

? die_addr+0x3c/0xa0

? exc_general_protection+0x148/0x220

? asm_exc_general_protection+0x22/0x30

? btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs]

? btrfs_zone_finish_endio.part.0+0x19/0x160 [btrfs]

btrfs_finish_one_ordered+0x7b8/0x1de0 [btrfs]

? rcu_is_watching+0x11/0xb0

? lock_release+0x47a/0x620

? btrfs_finish_ordered_zoned+0x59b/0x800 [btrfs]

? __pfx_btrfs_finish_one_ordered+0x10/0x10 [btrfs]

? btrfs_finish_ordered_zoned+0x358/0x800 [btrfs]

? __smp_call_single_queue+0x124/0x350

? rcu_is_watching+0x11/0xb0

btrfs_work_helper+0x19f/0xc60 [btrfs]

? __pfx_try_to_wake_up+0x10/0x10

? _raw_spin_unlock_irq+0x24/0x50

? rcu_is_watching+0x11/0xb0

process_one_work+0x8c1/0x1430

? __pfx_lock_acquire+0x10/0x10

? __pfx_process_one_work+0x10/0x10

? __pfx_do_raw_spin_lock+0x10/0x10

? _raw_spin_lock_irq+0x52/0x60

worker_thread+0x100/0x12c0

? __kthread_parkme+0xc1/0x1f0

? __pfx_worker_thread+0x10/0x10

kthread+0x2ea/0x3c0

? __pfx_kthread+0x10/0x10

ret_from_fork+0x30/0x70

? __pfx_kthread+0x10/0x10

ret_from_fork_asm+0x1b/0x30

</TASK>

On the zoned mode, writing to pre-allocated region means data relocation

write. Such write always uses WRITE command so there is no need of splitting

and rewriting logical address. Thus, we can just skip the function for the

case.