On 1/19/2024 10:38 PM, Greg Kroah-Hartman wrote:
On Fri, Jan 19, 2024 at 05:38:11PM +0100, Stefan Wiehler wrote:
rcu_cpu_starting() must be called before clockevents_register_device() to avoid the following lockdep splat triggered by calling list_add() when CONFIG_PROVE_RCU_LIST=y:
WARNING: suspicious RCU usage ...
kernel/locking/lockdep.c:3680 RCU-list traversed in non-reader section!!
other info that might help us debug this:
RCU used illegally from offline CPU! rcu_scheduler_active = 1, debug_locks = 1 no locks held by swapper/1/0. ... Call Trace: [<ffffffff8012a434>] show_stack+0x64/0x158 [<ffffffff80a93d98>] dump_stack_lvl+0x90/0xc4 [<ffffffff801c9e9c>] __lock_acquire+0x1404/0x2940 [<ffffffff801cbf3c>] lock_acquire+0x14c/0x448 [<ffffffff80aa4260>] _raw_spin_lock_irqsave+0x50/0x88 [<ffffffff8021e0c8>] clockevents_register_device+0x60/0x1e8 [<ffffffff80130ff0>] r4k_clockevent_init+0x220/0x3a0 [<ffffffff801339d0>] start_secondary+0x50/0x3b8
raw_smp_processor_id() is required in order to avoid calling into lockdep before RCU has declared the CPU to be watched for readers.
See also commit 29368e093921 ("x86/smpboot: Move rcu_cpu_starting() earlier"), commit de5d9dae150c ("s390/smp: move rcu_cpu_starting() earlier") and commit 99f070b62322 ("powerpc/smp: Call rcu_cpu_starting() earlier").
Signed-off-by: Stefan Wiehler stefan.wiehler@nokia.com Reviewed-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de
arch/mips/kernel/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
What is the git commit id of this change in Linus's tree? What kernel(s) should this be applied to?
The upstream commit is 55702ec9603ebeffb15e6f7b113623fe1d8872f4 ("mips/smp: Call rcutree_report_cpu_starting() earlier") and this change from Stefan should be applied to both the 6.1 stable and 6.6 stable branches. Thanks!