Description

In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix softlockup in ftrace_module_enable A soft lockup was observed when loading amdgpu module. If a module has a lot of tracable functions, multiple calls to kallsyms_lookup can spend too much time in RCU critical section and with disabled preemption, causing kernel panic. This is the same issue that was fixed in commit d0b24b4e91fc ("ftrace: Prevent RCU stall on PREEMPT_VOLUNTARY kernels") and commit 42ea22e754ba ("ftrace: Add cond_resched() to ftrace_graph_set_hash()"). Fix it the same way by adding cond_resched() in ftrace_module_enable.

References 5

• git.kernel.org https://git.kernel.org/stable/c/4099b98203d6b33d990586542fa5beee408032a3
• git.kernel.org https://git.kernel.org/stable/c/40c8ee40e48a2c82c762539952ed8fc0571db5bf
• git.kernel.org https://git.kernel.org/stable/c/7e3c96010ade29bb340a5bdce8675f50c7f59001
• git.kernel.org https://git.kernel.org/stable/c/a1dd0abd741a8111260676da729825d6c1461a71
• git.kernel.org https://git.kernel.org/stable/c/e81e6d6d99b16dae11adbeda5c996317942a940c

Remediation