CVE-2023-54080
Unknown Unknown - Not Provided
Null Pointer Dereference in Linux Kernel btrfs Zoned Write Handling

Publication date: 2025-12-24

Last updated on: 2025-12-24

Assigner: kernel.org

Description
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.
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Meta Information
Published
2025-12-24
Last Modified
2025-12-24
Generated
2026-05-07
AI Q&A
2025-12-24
EPSS Evaluated
2026-05-05
NVD
CVE-2023-54080
EUVD
EUVD-2023-60365
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux kernel *
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability in the Linux kernel's btrfs filesystem occurs during data relocation in zoned mode. Specifically, when writing to a pre-allocated region, there can be a missing checksum for the corresponding region at the time of btrfs_reloc_clone_csums(). This causes btrfs_finish_ordered_zoned() to reference an invalid item, leading to an invalid logical address. Subsequently, btrfs_lookup_block_group() fails to find a block group and triggers an assertion failure or a null pointer dereference, potentially causing a kernel crash. The issue arises because splitting and logical rewriting are not needed for pre-allocated writes in zoned mode, but the function handling this was not properly skipped, leading to the error.


How can this vulnerability impact me? :

This vulnerability can cause a kernel crash due to a null pointer dereference when the btrfs filesystem handles data relocation writes in zoned mode. This can lead to system instability, potential data loss, or denial of service as the kernel may panic or become unresponsive during these operations.


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