In the Linux kernel, the following vulnerability has been resolved: btrfs: fix deadlock when cloning inline extents and using qgroups There are a few exceptional cases where cloning an inline extent needs to copy the inline extent data into a page of the destination inode. When this happens, we end up starting a transaction while having a dirty page for the destination inode and while having the range locked in the destination's inode iotree too. Because when reserving metadata space for a transaction we may need to flush existing delalloc in case there is not enough free space, we have a mechanism in place to prevent a deadlock, which was introduced in commit 3d45f221ce627d ("btrfs: fix deadlock when cloning inline extent and low on free metadata space"). However when using qgroups, a transaction also reserves metadata qgroup space, which can also result in flushing delalloc in case there is not enough available space at the moment. When this happens we deadlock, since flushing delalloc requires locking the file range in the inode's iotree and the range was already locked at the very beginning of the clone operation, before attempting to start the transaction. When this issue happens, stack traces like the following are reported: [72747.556262] task:kworker/u81:9 state:D stack: 0 pid: 225 ppid: 2 flags:0x00004000 [72747.556268] Workqueue: writeback wb_workfn (flush-btrfs-1142) [72747.556271] Call Trace: [72747.556273] __schedule+0x296/0x760 [72747.556277] schedule+0x3c/0xa0 [72747.556279] io_schedule+0x12/0x40 [72747.556284] __lock_page+0x13c/0x280 [72747.556287] ? generic_file_readonly_mmap+0x70/0x70 [72747.556325] extent_write_cache_pages+0x22a/0x440 [btrfs] [72747.556331] ? __set_page_dirty_nobuffers+0xe7/0x160 [72747.556358] ? set_extent_buffer_dirty+0x5e/0x80 [btrfs] [72747.556362] ? update_group_capacity+0x25/0x210 [72747.556366] ? cpumask_next_and+0x1a/0x20 [72747.556391] extent_writepages+0x44/0xa0 [btrfs] [72747.556394] do_writepages+0x41/0xd0 [72747.556398] __writeback_single_inode+0x39/0x2a0 [72747.556403] writeback_sb_inodes+0x1ea/0x440 [72747.556407] __writeback_inodes_wb+0x5f/0xc0 [72747.556410] wb_writeback+0x235/0x2b0 [72747.556414] ? get_nr_inodes+0x35/0x50 [72747.556417] wb_workfn+0x354/0x490 [72747.556420] ? newidle_balance+0x2c5/0x3e0 [72747.556424] process_one_work+0x1aa/0x340 [72747.556426] worker_thread+0x30/0x390 [72747.556429] ? create_worker+0x1a0/0x1a0 [72747.556432] kthread+0x116/0x130 [72747.556435] ? kthread_park+0x80/0x80 [72747.556438] ret_from_fork+0x1f/0x30 [72747.566958] Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] [72747.566961] Call Trace: [72747.566964] __schedule+0x296/0x760 [72747.566968] ? finish_wait+0x80/0x80 [72747.566970] schedule+0x3c/0xa0 [72747.566995] wait_extent_bit.constprop.68+0x13b/0x1c0 [btrfs] [72747.566999] ? finish_wait+0x80/0x80 [72747.567024] lock_extent_bits+0x37/0x90 [btrfs] [72747.567047] btrfs_invalidatepage+0x299/0x2c0 [btrfs] [72747.567051] ? find_get_pages_range_tag+0x2cd/0x380 [72747.567076] __extent_writepage+0x203/0x320 [btrfs] [72747.567102] extent_write_cache_pages+0x2bb/0x440 [btrfs] [72747.567106] ? update_load_avg+0x7e/0x5f0 [72747.567109] ? enqueue_entity+0xf4/0x6f0 [72747.567134] extent_writepages+0x44/0xa0 [btrfs] [72747.567137] ? enqueue_task_fair+0x93/0x6f0 [72747.567140] do_writepages+0x41/0xd0 [72747.567144] __filemap_fdatawrite_range+0xc7/0x100 [72747.567167] btrfs_run_delalloc_work+0x17/0x40 [btrfs] [72747.567195] btrfs_work_helper+0xc2/0x300 [btrfs] [72747.567200] process_one_work+0x1aa/0x340 [72747.567202] worker_thread+0x30/0x390 [72747.567205] ? create_worker+0x1a0/0x1a0 [72747.567208] kthread+0x116/0x130 [72747.567211] ? kthread_park+0x80/0x80 [72747.567214] ret_from_fork+0x1f/0x30 [72747.569686] task:fsstress state:D stack: ---truncated---

The remote SUSE Linux SLES12 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2025:02846-1 advisory.

    The SUSE Linux Enterprise 12 SP5 kernel was updated to receive various security bugfixes.


    The following security bugs were fixed:

    - CVE-2021-46984: Fixed an out of bounds access in kyber_bio_merge() in kyber (bsc#1220631).
    - CVE-2021-46987: btrfs: fix deadlock when cloning inline extents and using qgroups (bsc#1220704).
    - CVE-2022-4129: Fixed a denial of service with the Layer 2 Tunneling Protocol (L2TP). A missing lock when     clearing sk_user_data can lead to a race condition and NULL pointer dereference (bsc#1205711).
    - CVE-2022-49138: Bluetooth: hci_event: Fix checking conn for le_conn_complete_evt (bsc#1238160).
    - CVE-2022-49319: iommu/arm-smmu-v3: check return value after calling platform_get_resource()     (bsc#1238374).
    - CVE-2022-49323: iommu/arm-smmu: fix possible null-ptr-deref in arm_smmu_device_probe() (bsc#1238400).
    - CVE-2022-49768: 9p/fd: fix issue of list_del corruption in p9_fd_cancel() (bsc#1242446).
    - CVE-2022-49825: ata: libata-transport: fix error handling in ata_tport_add() (bsc#1242548).
    - CVE-2022-49934: wifi: mac80211: Fix UAF in ieee80211_scan_rx() (bsc#1245051).
    - CVE-2022-49948: vt: Clear selection before changing the font (bsc#1245058).
    - CVE-2022-49969: drm/amd/display: clear optc underflow before turn off odm clock (bsc#1245060).
    - CVE-2022-49993: loop: Check for overflow while configuring loop (bsc#1245121).
    - CVE-2022-50025: cxl: Fix a memory leak in an error handling path (bsc#1245132).
    - CVE-2022-50027: scsi: lpfc: Fix possible memory leak when failing to issue CMF WQE (bsc#1245073).
    - CVE-2022-50030: scsi: lpfc: Prevent buffer overflow crashes in debugfs with malformed user input     (bsc#1245265).
    - CVE-2022-50033: usb: host: ohci-ppc-of: Fix refcount leak bug (bsc#1245139).
    - CVE-2022-50103: sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed (bsc#1244840).
    - CVE-2022-50149: driver core: fix potential deadlock in __driver_attach (bsc#1244883).
    - CVE-2022-50226: crypto: ccp - Use kzalloc for sev ioctl interfaces to prevent kernel memory leak     (bsc#1244860).
    - CVE-2023-2176: Fixed an out-of-boundary read in compare_netdev_and_ip in drivers/infiniband/core/cma.c     in RDMA (bsc#1210629).
    - CVE-2023-52878: can: dev: can_put_echo_skb(): do not crash kernel if can_priv::echo_skb is accessed out     of bounds (bsc#1225000).
    - CVE-2023-53020: l2tp: close all race conditions in l2tp_tunnel_register() (bsc#1240224).
    - CVE-2023-53117: fs: prevent out-of-bounds array speculation when closing a file descriptor     (bsc#1242780).
    - CVE-2023-53118: scsi: core: Fix a procfs host directory removal regression (bsc#1242365).
    - CVE-2024-26974: crypto: qat - resolve race condition during AER recovery (bsc#1223638).
    - CVE-2024-26982: Fixed Squashfs inode number check not to be an invalid value of zero (bsc#1223634).
    - CVE-2024-44963: btrfs: do not BUG_ON() when freeing tree block after error (bsc#1230216).
    - CVE-2024-46713: kabi fix for perf/aux: Fix AUX buffer serialization (bsc#1230581).
    - CVE-2024-49861: net: clear the dst when changing skb protocol (bsc#1245954).
    - CVE-2025-21731: nbd: do not allow reconnect after disconnect (bsc#1237881).
    - CVE-2025-21928: HID: intel-ish-hid: Fix use-after-free issue in ishtp_hid_remove() (bsc#1240722).
    - CVE-2025-23163: net: vlan: do not propagate flags on open (bsc#1242837).
    - CVE-2025-37856: btrfs: harden block_group::bg_list against list_del() races (bsc#1243068).
    - CVE-2025-37885: KVM: x86: Reset IRTE to host control if *new* route isn't postable (bsc#1242960).
    - CVE-2025-37920: kABI workaround for xsk: Fix race condition in AF_XDP generic RX path (bsc#1243479).
    - CVE-2025-38034: btrfs: correct the order of prelim_ref arguments in btrfs__prelim_ref (bsc#1244792).
    - CVE-2025-38035: nvmet-tcp: do not restore null sk_state_change (bsc#1244801).
    - CVE-2025-38040: serial: mctrl_gpio: split disable_ms into sync and no_sync APIs (bsc#1245078).
    - CVE-2025-38051: smb: client: Fix use-after-free in cifs_fill_dirent (bsc#1244750).
    - CVE-2025-38058: __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock (bsc#1245151).
    - CVE-2025-38064: virtio: break and reset virtio devices on device_shutdown() (bsc#1245201).
    - CVE-2025-38068: crypto: lzo - Fix compression buffer overrun (bsc#1245210).
    - CVE-2025-38074: vhost-scsi: protect vq->log_used with vq->mutex (bsc#1244735).
    - CVE-2025-38079: crypto: algif_hash - fix double free in hash_accept (bsc#1245217).
    - CVE-2025-38094: net: cadence: macb: Fix a possible deadlock in macb_halt_tx (bsc#1245649).
    - CVE-2025-38105: ALSA: usb-audio: Kill timer properly at removal (bsc#1245682).
    - CVE-2025-38108: net_sched: red: fix a race in __red_change() (bsc#1245675).
    - CVE-2025-38112: net: Fix TOCTOU issue in sk_is_readable() (bsc#1245668).
    - CVE-2025-38115: net_sched: sch_sfq: fix a potential crash on gso_skb handling (bsc#1245689).
    - CVE-2025-38126: net: stmmac: make sure that ptp_rate is not 0 before configuring timestamping     (bsc#1245708).
    - CVE-2025-38147: calipso: unlock rcu before returning -EAFNOSUPPORT (bsc#1245768).
    - CVE-2025-38157: wifi: ath9k_htc: Abort software beacon handling if disabled (bsc#1245747).
    - CVE-2025-38161: RDMA/mlx5: Fix error flow upon firmware failure for RQ destruction (bsc#1245777).
    - CVE-2025-38166: bpf: fix ktls panic with sockmap (bsc#1245758).
    - CVE-2025-38180: net: atm: fix /proc/net/atm/lec handling (bsc#1245970).
    - CVE-2025-38181: calipso: Fix null-ptr-deref in calipso_req_{set,del}attr() (bsc#1246000).
    - CVE-2025-38193: net_sched: sch_sfq: reject invalid perturb period (bsc#1245945).
    - CVE-2025-38198: fbcon: Make sure modelist not set on unregistered console (bsc#1245952).
    - CVE-2025-38200: i40e: fix MMIO write access to an invalid page in i40e_clear_hw (bsc#1246045).
    - CVE-2025-38211: RDMA/iwcm: Fix use-after-free of work objects after cm_id destruction (bsc#1246008).
    - CVE-2025-38212: ipc: fix to protect IPCS lookups using RCU (bsc#1246029).
    - CVE-2025-38213: vgacon: Add check for vc_origin address range in vgacon_scroll() (bsc#1246037).
    - CVE-2025-38222: ext4: inline: fix len overflow in ext4_prepare_inline_data (bsc#1245976).
    - CVE-2025-38249: ALSA: usb-audio: Fix out-of-bounds read in snd_usb_get_audioformat_uac3() (bsc#1246171).
    - CVE-2025-38250: kABI workaround for bluetooth hci_dev changes (bsc#1246182).
    - CVE-2025-38264: llist: add interface to check if a node is on a list (bsc#1246387).
    - CVE-2025-38312: fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod() (bsc#1246386).
    - CVE-2025-38319: drm/amd/pp: Fix potential NULL pointer dereference in atomctrl_initialize_mc_reg_table     (bsc#1246243).
    - CVE-2025-38323: net: atm: add lec_mutex (bsc#1246473).
    - CVE-2025-38337: jbd2: fix data-race and null-ptr-deref in jbd2_journal_dirty_metadata() (bsc#1246253).
    - CVE-2025-38350: net/sched: Always pass notifications when child class becomes empty (bsc#1246781).
    - CVE-2025-38375: virtio-net: ensure the received length does not exceed allocated size (bsc#1247177).
    - CVE-2025-38391: usb: typec: altmodes/displayport: do not index invalid pin_assignments (bsc#1247181).
    - CVE-2025-38403: vsock/vmci: Clear the vmci transport packet properly when initializing it (bsc#1247141).
    - CVE-2025-38415: Squashfs: check return result of sb_min_blocksize (bsc#1247147).
    - CVE-2025-38420: wifi: carl9170: do not ping device which has failed to load firmware (bsc#1247279).
    - CVE-2025-38468: net/sched: Return NULL when htb_lookup_leaf encounters an empty rbtree (bsc#1247437).
    - CVE-2025-38477: net/sched: sch_qfq: Avoid triggering might_sleep in atomic context in qfq_delete_class     (bsc#1247314).
    - CVE-2025-38494: HID: core: do not bypass hid_hw_raw_request (bsc#1247349).
    - CVE-2025-38495: HID: core: ensure the allocated report buffer can contain the reserved report ID     (bsc#1247348).


Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

An update of the linux package has been released.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - btrfs: fix deadlock when cloning inline extents and using qgroups There are a few exceptional cases where     cloning an inline extent needs to copy the inline extent data into a page of the destination inode. When     this happens, we end up starting a transaction while having a dirty page for the destination inode and     while having the range locked in the destination's inode iotree too. Because when reserving metadata space     for a transaction we may need to flush existing delalloc in case there is not enough free space, we have a     mechanism in place to prevent a deadlock, which was introduced in commit 3d45f221ce627d (btrfs: fix     deadlock when cloning inline extent and low on free metadata space). However when using qgroups, a     transaction also reserves metadata qgroup space, which can also result in flushing delalloc in case there     is not enough available space at the moment. When this happens we deadlock, since flushing delalloc     requires locking the file range in the inode's iotree and the range was already locked at the very     beginning of the clone operation, before attempting to start the transaction. When this issue happens,     stack traces like the following are reported: [72747.556262] task:kworker/u81:9 state:D stack: 0 pid: 225     ppid: 2 flags:0x00004000 [72747.556268] Workqueue: writeback wb_workfn (flush-btrfs-1142) [72747.556271]     Call Trace: [72747.556273] __schedule+0x296/0x760 [72747.556277] schedule+0x3c/0xa0 [72747.556279]     io_schedule+0x12/0x40 [72747.556284] __lock_page+0x13c/0x280 [72747.556287] ?     generic_file_readonly_mmap+0x70/0x70 [72747.556325] extent_write_cache_pages+0x22a/0x440 [btrfs]     [72747.556331] ? __set_page_dirty_nobuffers+0xe7/0x160 [72747.556358] ? set_extent_buffer_dirty+0x5e/0x80     [btrfs] [72747.556362] ? update_group_capacity+0x25/0x210 [72747.556366] ? cpumask_next_and+0x1a/0x20     [72747.556391] extent_writepages+0x44/0xa0 [btrfs] [72747.556394] do_writepages+0x41/0xd0 [72747.556398]
    __writeback_single_inode+0x39/0x2a0 [72747.556403] writeback_sb_inodes+0x1ea/0x440 [72747.556407]
    __writeback_inodes_wb+0x5f/0xc0 [72747.556410] wb_writeback+0x235/0x2b0 [72747.556414] ?     get_nr_inodes+0x35/0x50 [72747.556417] wb_workfn+0x354/0x490 [72747.556420] ? newidle_balance+0x2c5/0x3e0     [72747.556424] process_one_work+0x1aa/0x340 [72747.556426] worker_thread+0x30/0x390 [72747.556429] ?     create_worker+0x1a0/0x1a0 [72747.556432] kthread+0x116/0x130 [72747.556435] ? kthread_park+0x80/0x80     [72747.556438] ret_from_fork+0x1f/0x30 [72747.566958] Workqueue: btrfs-flush_delalloc btrfs_work_helper     [btrfs] [72747.566961] Call Trace: [72747.566964] __schedule+0x296/0x760 [72747.566968] ?     finish_wait+0x80/0x80 [72747.566970] schedule+0x3c/0xa0 [72747.566995]     wait_extent_bit.constprop.68+0x13b/0x1c0 [btrfs] [72747.566999] ? finish_wait+0x80/0x80 [72747.567024]     lock_extent_bits+0x37/0x90 [btrfs] [72747.567047] btrfs_invalidatepage+0x299/0x2c0 [btrfs] [72747.567051]     ? find_get_pages_range_tag+0x2cd/0x380 [72747.567076] __extent_writepage+0x203/0x320 [btrfs]     [72747.567102] extent_write_cache_pages+0x2bb/0x440 [btrfs] [72747.567106] ? update_load_avg+0x7e/0x5f0     [72747.567109] ? enqueue_entity+0xf4/0x6f0 [72747.567134] extent_writepages+0x44/0xa0 [btrfs]     [72747.567137] ? enqueue_task_fair+0x93/0x6f0 [72747.567140] do_writepages+0x41/0xd0 [72747.567144]
    __filemap_fdatawrite_range+0xc7/0x100 [72747.567167] btrfs_run_delalloc_work+0x17/0x40 [btrfs]     [72747.567195] btrfs_work_helper+0xc2/0x300 [btrfs] [72747.567200] process_one_work+0x1aa/0x340     [72747.567202] worker_thread+0x30/0x390 [72747.567205] ? create_worker+0x1a0/0x1a0 [72747.567208]     kthread+0x116/0x130 [72747.567211] ? kthread_park+0x80/0x80 [72747.567214] ret_from_fork+0x1f/0x30     [72747.569686] task:fsstress state:D stack: ---truncated--- (CVE-2021-46987)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
252257	SUSE SLES12 Security Update : kernel (SUSE-SU-2025:02846-1)	Nessus	SuSE Local Security Checks	high
242874	Photon OS 4.0: Linux PHSA-2025-4.0-0834	Nessus	PhotonOS Local Security Checks	medium
230151	Linux Distros Unpatched Vulnerability : CVE-2021-46987	Nessus	Misc.	medium

Detections

Analytics

CVE-2021-46987

medium

Tenable Plugins

high

medium

medium