CVE-2025-37871 — nfsd: decrease sc_count directly if fail to queue dl_recall

Affected: Linux

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

nfsd: decrease sc_count directly if fail to queue dl_recall

A deadlock warning occurred when invoking nfs4_put_stid following a failed dl_recall queue operation: T1 T2 nfs4_laundromat nfs4_get_client_reaplist nfs4_anylock_blockers __break_lease spin_lock // ctx->flc_lock spin_lock // clp->cl_lock nfs4_lockowner_has_blockers locks_owner_has_blockers spin_lock // flctx->flc_lock nfsd_break_deleg_cb nfsd_break_one_deleg nfs4_put_stid refcount_dec_and_lock spin_lock // clp->cl_lock

When a file is opened, an nfs4_delegation is allocated with sc_count initialized to 1, and the file_lease holds a reference to the delegation. The file_lease is then associated with the file through kernel_setlease.

The disassociation is performed in nfsd4_delegreturn via the following call chain: nfsd4_delegreturn --> destroy_delegation --> destroy_unhashed_deleg --> nfs4_unlock_deleg_lease --> kernel_setlease --> generic_delete_lease The corresponding sc_count reference will be released after this disassociation.

Since nfsd_break_one_deleg executes while holding the flc_lock, the disassociation process becomes blocked when attempting to…

USN-7654-1 — linux, linux-aws, linux-aws-5.15, linux-gcp, linux-gcp-5.15, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-i…

Affected: Ubuntu:Pro:20.04:LTS: linux-aws-5.15, Ubuntu:Pro:20.04:LTS: linux-gcp-5.15, Ubuntu:Pro:20.04:LTS: linux-hwe-5.15, Ubuntu:Pro:20.04:LTS: linux-ibm-5.15, Ubuntu:Pro:20.04:LTS: linux-lowlatency-hwe-5.15, Ubuntu:Pro:20.04:LTS: linux-nvidia-tegra-5.15, Ubuntu:Pro:20.04:LTS: linux-oracle-5.15, Ubuntu:22.04:LTS: linux, Ubuntu:22.04:LTS: linux-aws, Ubuntu:22.04:LTS: linux-gcp and 9 more

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - PA-RISC architecture; - PowerPC architecture; - x86 architecture; - Block layer subsystem; - Cryptographic API; - Serial ATA and Parallel ATA drivers; - Bluetooth drivers; - Bus devices; - CPU frequency scaling framework; - Buffer Sharing and Synchronization framework; - DMA engine subsystem; - ARM SCMI message protocol; - GPU drivers; - HID subsystem; - HSI subsystem; - I2C subsystem; - I3C subsystem; - IIO subsystem; - InfiniBand drivers; - IOMMU subsystem; - IRQ chip drivers; - MCB driver; - Multiple devices driver; - Media drivers; - Multifunction device drivers; - PCI Endpoint Test driver; - MTD block device drivers; - Network drivers; - Device tree and open firmware driver; - PCI subsystem; - TI SCI PM domains driver; - PWM drivers; - S/390 drivers; - SCSI subsystem; - Samsung SoC drivers; - TCM subsystem; - UFS subsystem; - Cadence USB3 driver; - ChipIdea USB driver; - USB Device Class drivers; - DesignWare USB3 driver; - USB Gadget drivers; - USB Type-C support driver; - USB Type-C Connector System Software Interface driver; - Backlight driver; - Framebuffer layer; - Xen hypervisor drivers; - BTRFS file system; - Ext4 file system; - F2FS file system; - File systems infrastructure; - JFS…

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CVE-2025-37871 — nfsd: decrease sc_count directly if fail to queue dl_recall

USN-7654-1 — linux, linux-aws, linux-aws-5.15, linux-gcp, linux-gcp-5.15, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-i…