When CONFIG_KASAN=y and CONFIG_KASAN_STACK=y builds, the show_rcu_gp_kthreads() exceeds the 1024-byte frame-size limit:
make kernel/rcu/tree.o KCFLAGS="-fstack-usage" DESCEND objtool DESCEND bpf/resolve_btfids INSTALL libsubcmd_headers CC kernel/rcu/tree.o In file included from kernel/rcu/tree.c:4998: kernel/rcu/tree_stall.h: In function 'show_rcu_gp_kthreads': kernel/rcu/tree_stall.h:994:1: warning: the frame size of 1656 bytes is larger than 1024 bytes [-Wframe-larger-than=] grep show_rcu kernel/rcu/tree.su tree_nocb.h:1622:13:show_rcu_nocb_state 896 dynamic,bounded tree_stall.h:933:6:show_rcu_gp_kthreads 1784 dynamic,bounded tree_stall.h:1102:13:sysrq_show_rcu 16 static Wrap the pr_info() into two noinline_for_stack helpers function: show_rcu_state() print rcu_state status, and show_rcu_node() print single rcu_node status. After apply this change: grep show_rcu kernel/rcu/tree.su tree_stall.h:955:22:show_rcu_node 696 dynamic,bounded tree_stall.h:930:22:show_rcu_state 872 dynamic,bounded tree_nocb.h:1622:13:show_rcu_nocb_state 896 dynamic,bounded tree_stall.h:972:6:show_rcu_gp_kthreads 544 static tree_stall.h:1113:13:sysrq_show_rcu 16 static Signed-off-by: Zqiang <[email protected]> --- kernel/rcu/tree_stall.h | 47 +++++++++++++++++++++++++---------------- 1 file changed, 29 insertions(+), 18 deletions(-) diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 45b9856ccd2b..a6dfd036a7e9 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -927,20 +927,13 @@ bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) } EXPORT_SYMBOL_GPL(rcu_check_boost_fail); -/* - * Show the state of the grace-period kthreads. - */ -void show_rcu_gp_kthreads(void) +static noinline_for_stack void show_rcu_state(void) { - unsigned long cbs = 0; - int cpu; unsigned long j; unsigned long ja; unsigned long jr; unsigned long js; unsigned long jw; - struct rcu_data *rdp; - struct rcu_node *rnp; struct task_struct *t = READ_ONCE(rcu_state.gp_kthread); j = jiffies; @@ -957,21 +950,39 @@ void show_rcu_gp_kthreads(void) (long)data_race(READ_ONCE(rcu_get_root()->gp_seq_needed)), data_race(READ_ONCE(rcu_state.gp_max)), data_race(READ_ONCE(rcu_state.gp_flags))); +} + +static noinline_for_stack void show_rcu_node(struct rcu_node *rnp) +{ + pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld ->qsmask %#lx %c%c%c%c ->n_boosts %ld\n", + rnp->grplo, rnp->grphi, + (long)data_race(READ_ONCE(rnp->gp_seq)), + (long)data_race(READ_ONCE(rnp->gp_seq_needed)), + data_race(READ_ONCE(rnp->qsmask)), + ".b"[!!data_race(READ_ONCE(rnp->boost_kthread_task))], + ".B"[!!data_race(READ_ONCE(rnp->boost_tasks))], + ".E"[!!data_race(READ_ONCE(rnp->exp_tasks))], + ".G"[!!data_race(READ_ONCE(rnp->gp_tasks))], + data_race(READ_ONCE(rnp->n_boosts))); +} + +/* + * Show the state of the grace-period kthreads. + */ +void show_rcu_gp_kthreads(void) +{ + unsigned long cbs = 0; + int cpu; + struct rcu_data *rdp; + struct rcu_node *rnp; + + show_rcu_state(); rcu_for_each_node_breadth_first(rnp) { if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq), READ_ONCE(rnp->gp_seq_needed)) && !data_race(READ_ONCE(rnp->qsmask)) && !data_race(READ_ONCE(rnp->boost_tasks)) && !data_race(READ_ONCE(rnp->exp_tasks)) && !data_race(READ_ONCE(rnp->gp_tasks))) continue; - pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld ->qsmask %#lx %c%c%c%c ->n_boosts %ld\n", - rnp->grplo, rnp->grphi, - (long)data_race(READ_ONCE(rnp->gp_seq)), - (long)data_race(READ_ONCE(rnp->gp_seq_needed)), - data_race(READ_ONCE(rnp->qsmask)), - ".b"[!!data_race(READ_ONCE(rnp->boost_kthread_task))], - ".B"[!!data_race(READ_ONCE(rnp->boost_tasks))], - ".E"[!!data_race(READ_ONCE(rnp->exp_tasks))], - ".G"[!!data_race(READ_ONCE(rnp->gp_tasks))], - data_race(READ_ONCE(rnp->n_boosts))); + show_rcu_node(rnp); if (!rcu_is_leaf_node(rnp)) continue; for_each_leaf_node_possible_cpu(rnp, cpu) { -- 2.17.1
