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

perf: Fix race between perf_event_exit_task() and perf_pending_task()

A race condition exists between perf_event_exit_task() and perf_pending_task() during begin_new_exec().

During begin_new_exec(), perf_event_exit_task() may be called, and the PF_EXITING flag is not set on task. So perf_sigtrap() continues to execute and triggers WARN_ON_ONCE(event->ctx->task != current).

Since both task exit and exec paths can call perf_event_exit_task() which sets ctx->task to TASK_TOMBSTONE, fix this by explicitly checking if event->ctx->task equals TASK_TOMBSTONE and dropping the redundant PF_EXITING check.

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

perf: Fix race between perf_event_exit_task() and perf_pending_task()

A race condition exists between perf_event_exit_task() and perf_pending_task() during begin_new_exec().

During begin_new_exec(), perf_event_exit_task() may be called, and the PF_EXITING flag is not set on task. So perf_sigtrap() continues to execute and triggers WARN_ON_ONCE(event->ctx->task != current).

Since both task exit and exec paths can call perf_event_exit_task() which sets ctx->task to TASK_TOMBSTONE, fix this by explicitly checking if event->ctx->task equals TASK_TOMBSTONE and dropping the redundant PF_EXITING check.

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 193 more

In the Linux kernel, the following vulnerability has been resolved: perf: Fix race between perf_event_exit_task() and perf_pending_task() A race condition exists between perf_event_exit_task() and perf_pending_task() during begin_new_exec(). During begin_new_exec(), perf_event_exit_task() may be called, and the PF_EXITING flag is not set on task. So perf_sigtrap() continues to execute and triggers WARN_ON_ONCE(event->ctx->task != current). Since both task exit and exec paths can call perf_event_exit_task() which sets ctx->task to TASK_TOMBSTONE, fix this by explicitly checking if event->ctx->task equals TASK_TOMBSTONE and dropping the redundant PF_EXITING check.

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen, möglicherweise einen Denial-of-Service-Angriff auszulösen, Daten zu manipulieren oder offenzulegen oder Sicherheitsmaßnahmen zu umgehen.