CVE-2026-98530 — kprobes: Fix permanent hang when flushing the kprobe optimizer

Affected: Linux

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

kprobes: Fix permanent hang when flushing the kprobe optimizer

Writing 0 to /proc/sys/debug/kprobes-optimization while a kprobe is jump-optimized never returns. The writer sleeps in D state forever with kprobe_sysctl_mutex held, so any later read or write of that sysctl hangs as well. For example, with vfs_read+9 as an optimizable address in this build:

# cd /sys/kernel/tracing # echo 'p:myprobe vfs_read+9' >> kprobe_events # echo 1 > events/kprobes/myprobe/enable # # wait until /sys/kernel/debug/kprobes/list shows [OPTIMIZED] # echo 0 > /proc/sys/debug/kprobes-optimization

INFO: task sh:246 blocked for more than 10 seconds. Call Trace: <TASK> __schedule+0x1176/0x4f70 schedule+0xdc/0x2c0 schedule_timeout+0x17b/0x260 wait_for_completion+0x173/0x3c0 wait_for_kprobe_optimizer_locked+0xbc/0x130 proc_kprobes_optimization_handler+0x156/0x1b0 proc_sys_call_handler+0x324/0x490 vfs_write+0x52d/0xfe0 ksys_write+0xff/0x200 do_syscall_64+0x106/0x630 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> ... INFO: task cat:265 is blocked on a mutex likely owned by task sh:246.

wait_for_kprobe_optimizer_locked() reinitializes optimizer_completion, asks the optimizer thread to flush and sleeps in wait_for_completion(). The thread drains the (un)optimizing lists, but calls complete() only if completion_done() is true, i.e. if the completion is already done, which never…

USN-8959-1 — linux, linux-aws, linux-gcp, linux-hwe-7.0, linux-ibm, linux-oracle vulnerabilities

Affected: Ubuntu:24.04:LTS: linux-hwe-7.0, Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-aws, Ubuntu:26.04:LTS: linux-gcp, Ubuntu:26.04:LTS: linux-ibm, Ubuntu:26.04:LTS: linux-oracle

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: - USB Gadget drivers; - Memory management; - Multiple devices driver; - ARM64 architecture; - EROFS file system; - Networking core; - eXpress Data Path; - ARM32 architecture; - M68K architecture; - MIPS architecture; - OpenRISC architecture; - PA-RISC architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - Compute Acceleration Framework; - Intel NPU Driver; - Speakup Console Speech Driver; - ACPI drivers; - Serial ATA and Parallel ATA drivers; - Auxiliary display drivers; - Drivers core; - Micron PCIe SSD driver; - Null block device driver; - Ublk userspace block driver; - Compressed RAM block device driver; - Bluetooth drivers; - Bus devices; - AMD CDX bus driver; - Hardware random number generator core; - Character device driver; - TPM device driver; - Clock framework and drivers; - Clocksource drivers; - CPU frequency scaling framework; - CPU idle management framework; - Hardware crypto device drivers; - CXL (Compute Express Link) drivers; - DAX dirext access to differentiated memory framework; - DIBS (Direct Internal Buffer Sharing) drivers; - Buffer Sharing and Synchronization framework;…

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CVE-2026-98530 — kprobes: Fix permanent hang when flushing the kprobe optimizer

USN-8959-1 — linux, linux-aws, linux-gcp, linux-hwe-7.0, linux-ibm, linux-oracle vulnerabilities