CVE-2024-53176 — smb: During unmount, ensure all cached dir instances drop their dentry

Affected: Linux

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

smb: During unmount, ensure all cached dir instances drop their dentry

The unmount process (cifs_kill_sb() calling close_all_cached_dirs()) can race with various cached directory operations, which ultimately results in dentries not being dropped and these kernel BUGs:

BUG: Dentry ffff88814f37e358{i=1000000000080,n=/} still in use (2) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) ------------[ cut here ]------------ kernel BUG at fs/super.c:661!

This happens when a cfid is in the process of being cleaned up when, and has been removed from the cfids->entries list, including:

- Receiving a lease break from the server - Server reconnection triggers invalidate_all_cached_dirs(), which removes all the cfids from the list - The laundromat thread decides to expire an old cfid.

To solve these problems, dropping the dentry is done in queued work done in a newly-added cfid_put_wq workqueue, and close_all_cached_dirs() flushes that workqueue after it drops all the dentries of which it's aware. This is a global workqueue (rather than scoped to a mount), but the queued work is minimal.

The final cleanup work for cleaning up a cfid is performed via work queued in the serverclose_wq workqueue; this is done separate from dropping the dentries so that close_all_cached_dirs() doesn't block on any server operations.

Both of these queued works expect to invoked with a cfid reference and a tcon r…

USN-7276-1 — linux, linux-lowlatency vulnerabilities

Affected: Ubuntu:24.10: linux, Ubuntu:24.10: linux-lowlatency

Attila Szász discovered that the HFS+ file system implementation in the Linux Kernel contained a heap overflow vulnerability. An attacker could use a specially crafted file system image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2025-0927)

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: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - SuperH RISC architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - Compute Acceleration Framework; - ACPI drivers; - Drivers core; - ATA over ethernet (AOE) driver; - RAM backed block device driver; - Network block device driver; - Ublk userspace block driver; - Compressed RAM block device driver; - Bluetooth drivers; - TPM device driver; - Clock framework and drivers; - Data acquisition framework and drivers; - CPU frequency scaling framework; - Hardware crypto device drivers; - CXL (Compute Express Link) drivers; - DAX dirext access to differentiated memory framework; - Buffer Sharing and Synchronization framework; - EDAC drivers; - FireWire subsystem; - ARM SCMI message protocol; - ARM SCPI message protocol; - EFI core; - Qualcomm firmware drivers; - GPIO subsystem;…

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CVE-2024-53176 — smb: During unmount, ensure all cached dir instances drop their dentry

USN-7276-1 — linux, linux-lowlatency vulnerabilities