bf940a84c8
We encountered an unexpected system reboot during a stress test, and based on the kernel warning backtrace, it looks like a race condition in the RCU subsystem caused this issue. It is similar to the issue reported at https://lore.kernel.org/all/20210917211148.GU4156@paulmck-ThinkPad-P17-Gen-1/#t Guillaume Morin applied two patches, then he can not reproduce it again. commit 2431774f04 [rcu: Mark accesses to rcu_state.n_force_qs] had been in upstream Linux kernel. https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/ commit/?h=rcu/next&id=325a2030b90376d179a129794e2fae2b24d73923 [rcu: Tighten rcu_advance_cbs_nowake() checks] Paul E. McKenney provided, which was not pushed to the mainline now. (It would be slated for the v5.17 merge window by default) Basically the rcu_advance_cbs() == true warning in rcu_advance_cbs_nowake() is firing then everything eventually gets stuck on RCU synchronization. WARNING: CPU: 35 PID: 2743975 at kernel/rcu/tree.c:1589 rcu_advance_cbs_nowake+0x78/0x80 ...... Call Trace: call_rcu+0x173/0x5c0 task_work_run+0x6d/0xa0 exit_to_user_mode_prepare+0x130/0x140 syscall_exit_to_user_mode+0x27/0x1d0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Verification: The formal regression tests were carried out by colleagues in the test team at Wind River, which include userspace packages, ltp and posix， basic networking test etc. Closes-Bug: #1952710 Signed-off-by: Jiping Ma <jiping.ma2@windriver.com> Change-Id: I4ee7d3d007edced81c9ac43c5850f941f1d393ee