Yang Yingliang (2): sched/smt: Introduce sched_smt_present_inc/dec() helper sched/smt: Fix unbalance sched_smt_present dec/inc
kernel/sched/core.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-)
From: Yang Yingliang yangyingliang@huawei.com
mainline inclusion from mainline-v6.11-rc1 commit 31b164e2e4af84d08d2498083676e7eeaa102493 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAOXYI CVE: CVE-2024-44958
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Introduce sched_smt_present_inc/dec() helper, so it can be called in normal or error path simply. No functional changed.
Cc: stable@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lore.kernel.org/r/20240703031610.587047-2-yangyingliang@huaweicloud....
Conflicts: kernel/sched/core.c [Some contexts around sched_cpu_deactivate different. No functional impact.] Signed-off-by: Zheng Zucheng zhengzucheng@huawei.com --- kernel/sched/core.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 81b58ce710ba..17a1b2e6582f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7965,18 +7965,31 @@ static int cpuset_cpu_inactive(unsigned int cpu) return 0; }
+static inline void sched_smt_present_inc(int cpu) +{ +#ifdef CONFIG_SCHED_SMT + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + static_branch_inc_cpuslocked(&sched_smt_present); +#endif +} + +static inline void sched_smt_present_dec(int cpu) +{ +#ifdef CONFIG_SCHED_SMT + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + static_branch_dec_cpuslocked(&sched_smt_present); +#endif +} + int sched_cpu_activate(unsigned int cpu) { struct rq *rq = cpu_rq(cpu); struct rq_flags rf;
-#ifdef CONFIG_SCHED_SMT /* * When going up, increment the number of cores with SMT present. */ - if (cpumask_weight(cpu_smt_mask(cpu)) == 2) - static_branch_inc_cpuslocked(&sched_smt_present); -#endif + sched_smt_present_inc(cpu); set_cpu_active(cpu, true);
if (sched_smp_initialized) { @@ -8017,13 +8030,12 @@ int sched_cpu_deactivate(unsigned int cpu) */ synchronize_rcu();
-#ifdef CONFIG_SCHED_SMT /* * When going down, decrement the number of cores with SMT present. */ - if (cpumask_weight(cpu_smt_mask(cpu)) == 2) - static_branch_dec_cpuslocked(&sched_smt_present); + sched_smt_present_dec(cpu);
+#ifdef CONFIG_SCHED_SMT sched_core_cpu_deactivate(cpu); #endif
From: Yang Yingliang yangyingliang@huawei.com
mainline inclusion from mainline-v6.11-rc1 commit e22f910a26cc2a3ac9c66b8e935ef2a7dd881117 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAOXYI CVE: CVE-2024-44958
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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I got the following warn report while doing stress test:
jump label: negative count! WARNING: CPU: 3 PID: 38 at kernel/jump_label.c:263 static_key_slow_try_dec+0x9d/0xb0 Call Trace: <TASK> __static_key_slow_dec_cpuslocked+0x16/0x70 sched_cpu_deactivate+0x26e/0x2a0 cpuhp_invoke_callback+0x3ad/0x10d0 cpuhp_thread_fun+0x3f5/0x680 smpboot_thread_fn+0x56d/0x8d0 kthread+0x309/0x400 ret_from_fork+0x41/0x70 ret_from_fork_asm+0x1b/0x30 </TASK>
Because when cpuset_cpu_inactive() fails in sched_cpu_deactivate(), the cpu offline failed, but sched_smt_present is decremented before calling sched_cpu_deactivate(), it leads to unbalanced dec/inc, so fix it by incrementing sched_smt_present in the error path.
Fixes: c5511d03ec09 ("sched/smt: Make sched_smt_present track topology") Cc: stable@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Chen Yu yu.c.chen@intel.com Reviewed-by: Tim Chen tim.c.chen@linux.intel.com Link: https://lore.kernel.org/r/20240703031610.587047-3-yangyingliang@huaweicloud....
Conflicts: kernel/sched/core.c [Some contexts around sched_cpu_deactivate different. No functional impact.] Signed-off-by: Zheng Zucheng zhengzucheng@huawei.com --- kernel/sched/core.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 17a1b2e6582f..9d34b3b53552 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8044,6 +8044,7 @@ int sched_cpu_deactivate(unsigned int cpu)
ret = cpuset_cpu_inactive(cpu); if (ret) { + sched_smt_present_inc(cpu); set_cpu_active(cpu, true); return ret; }
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