On 3/3/22 00:34, Andrew Morton wrote: > On Tue, 1 Mar 2022 20:38:25 -0500 wangjianxing <wangjianxing@xxxxxxxxxxx> wrote: > >> free a large list of pages maybe cause rcu_sched starved on >> non-preemptible kernels >> >> rcu: rcu_sched kthread starved for 5359 jiffies! g454793 f0x0 >> RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=19 >> [...] >> Call Trace: >> free_unref_page_list+0x19c/0x270 >> release_pages+0x3cc/0x498 >> tlb_flush_mmu_free+0x44/0x70 >> zap_pte_range+0x450/0x738 >> unmap_page_range+0x108/0x240 >> unmap_vmas+0x74/0xf0 >> unmap_region+0xb0/0x120 >> do_munmap+0x264/0x438 >> vm_munmap+0x58/0xa0 >> sys_munmap+0x10/0x20 >> syscall_common+0x24/0x38 > > Thanks. > > How did this large list of pages come about? Looks like it came from TLB batching. But I got lost in the maze of it trying to figure out how large the batch can grow. > Will people be seeing this message in upstream kernels, or is it > specific to some caller code which you have added? > > Please always include details such as this so that others can determine > whether the fix should be backported into -stable kernels. > >
