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FAILED: patch "[PATCH] sched/eevdf: Fix min_vruntime vs avg_vruntime" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 79f3f9bedd149ea438aaeb0fb6a083637affe205 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122903-sterile-from-4520@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 79f3f9bedd149ea438aaeb0fb6a083637affe205 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra <peterz(a)infradead.org> Date: Wed, 2 Apr 2025 20:07:34 +0200 Subject: [PATCH] sched/eevdf: Fix min_vruntime vs avg_vruntime Basically, from the constraint that the sum of lag is zero, you can infer that the 0-lag point is the weighted average of the individual vruntime, which is what we're trying to compute: \Sum w_i * v_i avg = -------------- \Sum w_i Now, since vruntime takes the whole u64 (worse, it wraps), this multiplication term in the numerator is not something we can compute; instead we do the min_vruntime (v0 henceforth) thing like: v_i = (v_i - v0) + v0 This does two things: - it keeps the key: (v_i - v0) 'small'; - it creates a relative 0-point in the modular space. If you do that subtitution and work it all out, you end up with: \Sum w_i * (v_i - v0) avg = --------------------- + v0 \Sum w_i Since you cannot very well track a ratio like that (and not suffer terrible numerical problems) we simpy track the numerator and denominator individually and only perform the division when strictly needed. Notably, the numerator lives in cfs_rq->avg_vruntime and the denominator lives in cfs_rq->avg_load. The one extra 'funny' is that these numbers track the entities in the tree, and current is typically outside of the tree, so avg_vruntime() adds current when needed before doing the division. (vruntime_eligible() elides the division by cross-wise multiplication) Anyway, as mentioned above, we currently use the CFS era min_vruntime for this purpose. However, this thing can only move forward, while the above avg can in fact move backward (when a non-eligible task leaves, the average becomes smaller), this can cause trouble when through happenstance (or construction) these values drift far enough apart to wreck the game. Replace cfs_rq::min_vruntime with cfs_rq::zero_vruntime which is kept near/at avg_vruntime, following its motion. The down-side is that this requires computing the avg more often. Fixes: 147f3efaa241 ("sched/fair: Implement an EEVDF-like scheduling policy") Reported-by: Zicheng Qu <quzicheng(a)huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Link: https://patch.msgid.link/20251106111741.GC4068168@noisy.programming.kicks-a… Cc: stable(a)vger.kernel.org diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 02e16b70a790..41caa22e0680 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -796,7 +796,7 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu) void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) { - s64 left_vruntime = -1, min_vruntime, right_vruntime = -1, left_deadline = -1, spread; + s64 left_vruntime = -1, zero_vruntime, right_vruntime = -1, left_deadline = -1, spread; struct sched_entity *last, *first, *root; struct rq *rq = cpu_rq(cpu); unsigned long flags; @@ -819,15 +819,15 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) last = __pick_last_entity(cfs_rq); if (last) right_vruntime = last->vruntime; - min_vruntime = cfs_rq->min_vruntime; + zero_vruntime = cfs_rq->zero_vruntime; raw_spin_rq_unlock_irqrestore(rq, flags); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "left_deadline", SPLIT_NS(left_deadline)); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "left_vruntime", SPLIT_NS(left_vruntime)); - SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "min_vruntime", - SPLIT_NS(min_vruntime)); + SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "zero_vruntime", + SPLIT_NS(zero_vruntime)); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "avg_vruntime", SPLIT_NS(avg_vruntime(cfs_rq))); SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "right_vruntime", diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 4a11a832d63e..8d971d48669f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -554,7 +554,7 @@ static inline bool entity_before(const struct sched_entity *a, static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) { - return (s64)(se->vruntime - cfs_rq->min_vruntime); + return (s64)(se->vruntime - cfs_rq->zero_vruntime); } #define __node_2_se(node) \ @@ -606,13 +606,13 @@ static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) * * Which we track using: * - * v0 := cfs_rq->min_vruntime + * v0 := cfs_rq->zero_vruntime * \Sum (v_i - v0) * w_i := cfs_rq->avg_vruntime * \Sum w_i := cfs_rq->avg_load * - * Since min_vruntime is a monotonic increasing variable that closely tracks - * the per-task service, these deltas: (v_i - v), will be in the order of the - * maximal (virtual) lag induced in the system due to quantisation. + * Since zero_vruntime closely tracks the per-task service, these + * deltas: (v_i - v), will be in the order of the maximal (virtual) lag + * induced in the system due to quantisation. * * Also, we use scale_load_down() to reduce the size. * @@ -671,7 +671,7 @@ u64 avg_vruntime(struct cfs_rq *cfs_rq) avg = div_s64(avg, load); } - return cfs_rq->min_vruntime + avg; + return cfs_rq->zero_vruntime + avg; } /* @@ -732,7 +732,7 @@ static int vruntime_eligible(struct cfs_rq *cfs_rq, u64 vruntime) load += weight; } - return avg >= (s64)(vruntime - cfs_rq->min_vruntime) * load; + return avg >= (s64)(vruntime - cfs_rq->zero_vruntime) * load; } int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se) @@ -740,42 +740,14 @@ int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se) return vruntime_eligible(cfs_rq, se->vruntime); } -static u64 __update_min_vruntime(struct cfs_rq *cfs_rq, u64 vruntime) +static void update_zero_vruntime(struct cfs_rq *cfs_rq) { - u64 min_vruntime = cfs_rq->min_vruntime; - /* - * open coded max_vruntime() to allow updating avg_vruntime - */ - s64 delta = (s64)(vruntime - min_vruntime); - if (delta > 0) { - avg_vruntime_update(cfs_rq, delta); - min_vruntime = vruntime; - } - return min_vruntime; -} + u64 vruntime = avg_vruntime(cfs_rq); + s64 delta = (s64)(vruntime - cfs_rq->zero_vruntime); -static void update_min_vruntime(struct cfs_rq *cfs_rq) -{ - struct sched_entity *se = __pick_root_entity(cfs_rq); - struct sched_entity *curr = cfs_rq->curr; - u64 vruntime = cfs_rq->min_vruntime; + avg_vruntime_update(cfs_rq, delta); - if (curr) { - if (curr->on_rq) - vruntime = curr->vruntime; - else - curr = NULL; - } - - if (se) { - if (!curr) - vruntime = se->min_vruntime; - else - vruntime = min_vruntime(vruntime, se->min_vruntime); - } - - /* ensure we never gain time by being placed backwards. */ - cfs_rq->min_vruntime = __update_min_vruntime(cfs_rq, vruntime); + cfs_rq->zero_vruntime = vruntime; } static inline u64 cfs_rq_min_slice(struct cfs_rq *cfs_rq) @@ -848,6 +820,7 @@ RB_DECLARE_CALLBACKS(static, min_vruntime_cb, struct sched_entity, static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) { avg_vruntime_add(cfs_rq, se); + update_zero_vruntime(cfs_rq); se->min_vruntime = se->vruntime; se->min_slice = se->slice; rb_add_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline, @@ -859,6 +832,7 @@ static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) rb_erase_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline, &min_vruntime_cb); avg_vruntime_sub(cfs_rq, se); + update_zero_vruntime(cfs_rq); } struct sched_entity *__pick_root_entity(struct cfs_rq *cfs_rq) @@ -1226,7 +1200,6 @@ static void update_curr(struct cfs_rq *cfs_rq) curr->vruntime += calc_delta_fair(delta_exec, curr); resched = update_deadline(cfs_rq, curr); - update_min_vruntime(cfs_rq); if (entity_is_task(curr)) { /* @@ -3808,15 +3781,6 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, if (!curr) __enqueue_entity(cfs_rq, se); cfs_rq->nr_queued++; - - /* - * The entity's vruntime has been adjusted, so let's check - * whether the rq-wide min_vruntime needs updated too. Since - * the calculations above require stable min_vruntime rather - * than up-to-date one, we do the update at the end of the - * reweight process. - */ - update_min_vruntime(cfs_rq); } } @@ -5429,15 +5393,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) update_cfs_group(se); - /* - * Now advance min_vruntime if @se was the entity holding it back, - * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be - * put back on, and if we advance min_vruntime, we'll be placed back - * further than we started -- i.e. we'll be penalized. - */ - if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE) - update_min_vruntime(cfs_rq); - if (flags & DEQUEUE_DELAYED) finish_delayed_dequeue_entity(se); @@ -9015,7 +8970,6 @@ static void yield_task_fair(struct rq *rq) if (entity_eligible(cfs_rq, se)) { se->vruntime = se->deadline; se->deadline += calc_delta_fair(se->slice, se); - update_min_vruntime(cfs_rq); } } @@ -13078,23 +13032,6 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) * Which shows that S and s_i transform alike (which makes perfect sense * given that S is basically the (weighted) average of s_i). * - * Then: - * - * x -> s_min := min{s_i} (8) - * - * to obtain: - * - * \Sum_i w_i (s_i - s_min) - * S = s_min + ------------------------ (9) - * \Sum_i w_i - * - * Which already looks familiar, and is the basis for our current - * approximation: - * - * S ~= s_min (10) - * - * Now, obviously, (10) is absolute crap :-), but it sorta works. - * * So the thing to remember is that the above is strictly UP. It is * possible to generalize to multiple runqueues -- however it gets really * yuck when you have to add affinity support, as illustrated by our very @@ -13116,23 +13053,23 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) * Let, for our runqueue 'k': * * T_k = \Sum_i w_i s_i - * W_k = \Sum_i w_i ; for all i of k (11) + * W_k = \Sum_i w_i ; for all i of k (8) * * Then we can write (6) like: * * T_k - * S_k = --- (12) + * S_k = --- (9) * W_k * * From which immediately follows that: * * T_k + T_l - * S_k+l = --------- (13) + * S_k+l = --------- (10) * W_k + W_l * * On which we can define a combined lag: * - * lag_k+l(i) := S_k+l - s_i (14) + * lag_k+l(i) := S_k+l - s_i (11) * * And that gives us the tools to compare tasks across a combined runqueue. * @@ -13143,7 +13080,7 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) * using (7); this only requires storing single 'time'-stamps. * * b) when comparing tasks between 2 runqueues of which one is forced-idle, - * compare the combined lag, per (14). + * compare the combined lag, per (11). * * Now, of course cgroups (I so hate them) make this more interesting in * that a) seems to suggest we need to iterate all cgroup on a CPU at such @@ -13191,12 +13128,11 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) * every tick. This limits the observed divergence due to the work * conservancy. * - * On top of that, we can improve upon things by moving away from our - * horrible (10) hack and moving to (9) and employing (13) here. + * On top of that, we can improve upon things by employing (10) here. */ /* - * se_fi_update - Update the cfs_rq->min_vruntime_fi in a CFS hierarchy if needed. + * se_fi_update - Update the cfs_rq->zero_vruntime_fi in a CFS hierarchy if needed. */ static void se_fi_update(const struct sched_entity *se, unsigned int fi_seq, bool forceidle) @@ -13210,7 +13146,7 @@ static void se_fi_update(const struct sched_entity *se, unsigned int fi_seq, cfs_rq->forceidle_seq = fi_seq; } - cfs_rq->min_vruntime_fi = cfs_rq->min_vruntime; + cfs_rq->zero_vruntime_fi = cfs_rq->zero_vruntime; } } @@ -13263,11 +13199,11 @@ bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b, /* * Find delta after normalizing se's vruntime with its cfs_rq's - * min_vruntime_fi, which would have been updated in prior calls + * zero_vruntime_fi, which would have been updated in prior calls * to se_fi_update(). */ delta = (s64)(sea->vruntime - seb->vruntime) + - (s64)(cfs_rqb->min_vruntime_fi - cfs_rqa->min_vruntime_fi); + (s64)(cfs_rqb->zero_vruntime_fi - cfs_rqa->zero_vruntime_fi); return delta > 0; } @@ -13513,7 +13449,7 @@ static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first) void init_cfs_rq(struct cfs_rq *cfs_rq) { cfs_rq->tasks_timeline = RB_ROOT_CACHED; - cfs_rq->min_vruntime = (u64)(-(1LL << 20)); + cfs_rq->zero_vruntime = (u64)(-(1LL << 20)); raw_spin_lock_init(&cfs_rq->removed.lock); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 82e74e8ca2ea..5a3cf81c27be 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -681,10 +681,10 @@ struct cfs_rq { s64 avg_vruntime; u64 avg_load; - u64 min_vruntime; + u64 zero_vruntime; #ifdef CONFIG_SCHED_CORE unsigned int forceidle_seq; - u64 min_vruntime_fi; + u64 zero_vruntime_fi; #endif struct rb_root_cached tasks_timeline;

3 days, 23 hours

FAILED: patch "[PATCH] sched_ext: Fix bypass depth leak on scx_enable() failure" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 9f769637a93fac81689b80df6855f545839cf999 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122940-sneak-unvocal-9de2@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 9f769637a93fac81689b80df6855f545839cf999 Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj(a)kernel.org> Date: Tue, 9 Dec 2025 11:04:33 -1000 Subject: [PATCH] sched_ext: Fix bypass depth leak on scx_enable() failure scx_enable() calls scx_bypass(true) to initialize in bypass mode and then scx_bypass(false) on success to exit. If scx_enable() fails during task initialization - e.g. scx_cgroup_init() or scx_init_task() returns an error - it jumps to err_disable while bypass is still active. scx_disable_workfn() then calls scx_bypass(true/false) for its own bypass, leaving the bypass depth at 1 instead of 0. This causes the system to remain permanently in bypass mode after a failed scx_enable(). Failures after task initialization is complete - e.g. scx_tryset_enable_state() at the end - already call scx_bypass(false) before reaching the error path and are not affected. This only affects a subset of failure modes. Fix it by tracking whether scx_enable() called scx_bypass(true) in a bool and having scx_disable_workfn() call an extra scx_bypass(false) to clear it. This is a temporary measure as the bypass depth will be moved into the sched instance, which will make this tracking unnecessary. Fixes: 8c2090c504e9 ("sched_ext: Initialize in bypass mode") Cc: stable(a)vger.kernel.org # v6.12+ Reported-by: Chris Mason <clm(a)meta.com> Reviewed-by: Emil Tsalapatis <emil(a)etsalapatis.com> Link: https://lore.kernel.org/stable/286e6f7787a81239e1ce2989b52391ce%40kernel.org Signed-off-by: Tejun Heo <tj(a)kernel.org> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index bd74b371f52d..c4465ccefea4 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -41,6 +41,13 @@ static bool scx_init_task_enabled; static bool scx_switching_all; DEFINE_STATIC_KEY_FALSE(__scx_switched_all); +/* + * Tracks whether scx_enable() called scx_bypass(true). Used to balance bypass + * depth on enable failure. Will be removed when bypass depth is moved into the + * sched instance. + */ +static bool scx_bypassed_for_enable; + static atomic_long_t scx_nr_rejected = ATOMIC_LONG_INIT(0); static atomic_long_t scx_hotplug_seq = ATOMIC_LONG_INIT(0); @@ -4318,6 +4325,11 @@ static void scx_disable_workfn(struct kthread_work *work) scx_dsp_max_batch = 0; free_kick_syncs(); + if (scx_bypassed_for_enable) { + scx_bypassed_for_enable = false; + scx_bypass(false); + } + mutex_unlock(&scx_enable_mutex); WARN_ON_ONCE(scx_set_enable_state(SCX_DISABLED) != SCX_DISABLING); @@ -4970,6 +4982,7 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) * Init in bypass mode to guarantee forward progress. */ scx_bypass(true); + scx_bypassed_for_enable = true; for (i = SCX_OPI_NORMAL_BEGIN; i < SCX_OPI_NORMAL_END; i++) if (((void (**)(void))ops)[i]) @@ -5067,6 +5080,7 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) scx_task_iter_stop(&sti); percpu_up_write(&scx_fork_rwsem); + scx_bypassed_for_enable = false; scx_bypass(false); if (!scx_tryset_enable_state(SCX_ENABLED, SCX_ENABLING)) {

3 days, 23 hours

FAILED: patch "[PATCH] sched_ext: Factor out local_dsq_post_enq() from" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 530b6637c79e728d58f1d9b66bd4acf4b735b86d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122922-chubby-doctrine-9c07@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 530b6637c79e728d58f1d9b66bd4acf4b735b86d Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj(a)kernel.org> Date: Thu, 11 Dec 2025 15:45:03 -1000 Subject: [PATCH] sched_ext: Factor out local_dsq_post_enq() from dispatch_enqueue() Factor out local_dsq_post_enq() which performs post-enqueue handling for local DSQs - triggering resched_curr() if SCX_ENQ_PREEMPT is specified or if the current CPU is idle. No functional change. This will be used by the next patch to fix move_local_task_to_local_dsq(). Cc: stable(a)vger.kernel.org # v6.12+ Reviewed-by: Andrea Righi <arighi(a)nvidia.com> Reviewed-by: Emil Tsalapatis <emil(a)etsalapatis.com> Signed-off-by: Tejun Heo <tj(a)kernel.org> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index c4465ccefea4..c78efa99406f 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -982,6 +982,22 @@ static void refill_task_slice_dfl(struct scx_sched *sch, struct task_struct *p) __scx_add_event(sch, SCX_EV_REFILL_SLICE_DFL, 1); } +static void local_dsq_post_enq(struct scx_dispatch_q *dsq, struct task_struct *p, + u64 enq_flags) +{ + struct rq *rq = container_of(dsq, struct rq, scx.local_dsq); + bool preempt = false; + + if ((enq_flags & SCX_ENQ_PREEMPT) && p != rq->curr && + rq->curr->sched_class == &ext_sched_class) { + rq->curr->scx.slice = 0; + preempt = true; + } + + if (preempt || sched_class_above(&ext_sched_class, rq->curr->sched_class)) + resched_curr(rq); +} + static void dispatch_enqueue(struct scx_sched *sch, struct scx_dispatch_q *dsq, struct task_struct *p, u64 enq_flags) { @@ -1093,22 +1109,10 @@ static void dispatch_enqueue(struct scx_sched *sch, struct scx_dispatch_q *dsq, if (enq_flags & SCX_ENQ_CLEAR_OPSS) atomic_long_set_release(&p->scx.ops_state, SCX_OPSS_NONE); - if (is_local) { - struct rq *rq = container_of(dsq, struct rq, scx.local_dsq); - bool preempt = false; - - if ((enq_flags & SCX_ENQ_PREEMPT) && p != rq->curr && - rq->curr->sched_class == &ext_sched_class) { - rq->curr->scx.slice = 0; - preempt = true; - } - - if (preempt || sched_class_above(&ext_sched_class, - rq->curr->sched_class)) - resched_curr(rq); - } else { + if (is_local) + local_dsq_post_enq(dsq, p, enq_flags); + else raw_spin_unlock(&dsq->lock); - } } static void task_unlink_from_dsq(struct task_struct *p,

3 days, 23 hours

[PATCH v5 3/3] KVM: x86: Add x2APIC "features" to control EOI broadcast suppression

by Khushit Shah

Add two flags for KVM_CAP_X2APIC_API to allow userspace to control support for Suppress EOI Broadcasts, which KVM completely mishandles. When x2APIC support was first added, KVM incorrectly advertised and "enabled" Suppress EOI Broadcast, without fully supporting the I/O APIC side of the equation, i.e. without adding directed EOI to KVM's in-kernel I/O APIC. That flaw was carried over to split IRQCHIP support, i.e. KVM advertised support for Suppress EOI Broadcasts irrespective of whether or not the userspace I/O APIC implementation supported directed EOIs. Even worse, KVM didn't actually suppress EOI broadcasts, i.e. userspace VMMs without support for directed EOI came to rely on the "spurious" broadcasts. KVM "fixed" the in-kernel I/O APIC implementation by completely disabling support for Suppress EOI Broadcasts in commit 0bcc3fb95b97 ("KVM: lapic: stop advertising DIRECTED_EOI when in-kernel IOAPIC is in use"), but didn't do anything to remedy userspace I/O APIC implementations. KVM's bogus handling of Suppress EOI Broadcast is problematic when the guest relies on interrupts being masked in the I/O APIC until well after the initial local APIC EOI. E.g. Windows with Credential Guard enabled handles interrupts in the following order: 1. Interrupt for L2 arrives. 2. L1 APIC EOIs the interrupt. 3. L1 resumes L2 and injects the interrupt. 4. L2 EOIs after servicing. 5. L1 performs the I/O APIC EOI. Because KVM EOIs the I/O APIC at step #2, the guest can get an interrupt storm, e.g. if the IRQ line is still asserted and userspace reacts to the EOI by re-injecting the IRQ, because the guest doesn't de-assert the line until step #4, and doesn't expect the interrupt to be re-enabled until step #5. Unfortunately, simply "fixing" the bug isn't an option, as KVM has no way of knowing if the userspace I/O APIC supports directed EOIs, i.e. suppressing EOI broadcasts would result in interrupts being stuck masked in the userspace I/O APIC due to step #5 being ignored by userspace. And fully disabling support for Suppress EOI Broadcast is also undesirable, as picking up the fix would require a guest reboot, *and* more importantly would change the virtual CPU model exposed to the guest without any buy-in from userspace. Add KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST and KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST flags to allow userspace to explicitly enable or disable support for Suppress EOI Broadcasts. This gives userspace control over the virtual CPU model exposed to the guest, as KVM should never have enabled support for Suppress EOI Broadcast without userspace opt-in. Not setting either flag will result in legacy quirky behavior for backward compatibility. When KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST is set and using in-kernel IRQCHIP mode, KVM will use I/O APIC version 0x20, which includes support for the EOI Register. Note, Suppress EOI Broadcasts is defined only in Intel's SDM, not in AMD's APM. But the bit is writable on some AMD CPUs, e.g. Turin, and KVM's ABI is to support Directed EOI (KVM's name) irrespective of guest CPU vendor. Fixes: 7543a635aa09 ("KVM: x86: Add KVM exit for IOAPIC EOIs") Closes: https://lore.kernel.org/kvm/7D497EF1-607D-4D37-98E7-DAF95F099342@nutanix.com Cc: stable(a)vger.kernel.org Suggested-by: David Woodhouse <dwmw2(a)infradead.org> Co-developed-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: Khushit Shah <khushit.shah(a)nutanix.com> --- Documentation/virt/kvm/api.rst | 28 +++++++++++++-- arch/x86/include/asm/kvm_host.h | 7 ++++ arch/x86/include/uapi/asm/kvm.h | 6 ++-- arch/x86/kvm/lapic.c | 64 ++++++++++++++++++++++----------- arch/x86/kvm/x86.c | 15 ++++++-- 5 files changed, 93 insertions(+), 27 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 57061fa29e6a..ad15ca519afc 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7800,8 +7800,10 @@ Will return -EBUSY if a VCPU has already been created. Valid feature flags in args[0] are:: - #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) - #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) + #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) + #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) + #define KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST (1ULL << 2) + #define KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST (1ULL << 3) Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, @@ -7814,6 +7816,28 @@ as a broadcast even in x2APIC mode in order to support physical x2APIC without interrupt remapping. This is undesirable in logical mode, where 0xff represents CPUs 0-7 in cluster 0. +Setting KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST instructs KVM to enable +Suppress EOI Broadcasts. KVM will advertise support for Suppress EOI +Broadcast to the guest and suppress LAPIC EOI broadcasts when the guest +sets the Suppress EOI Broadcast bit in the SPIV register. When using +in-kernel IRQCHIP mode, enabling this capability will cause KVM to use +I/O APIC version 0x20, which includes support for the EOI Register for +directed EOI. + +Setting KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST disables support for +Suppress EOI Broadcasts entirely, i.e. instructs KVM to NOT advertise +support to the guest. + +Modern VMMs should either enable KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST +or KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST. If not, legacy quirky +behavior will be used by KVM: in split IRQCHIP mode, KVM will advertise +support for Suppress EOI Broadcasts but not actually suppress EOI +broadcasts; for in-kernel IRQCHIP mode, KVM will not advertise support for +Suppress EOI Broadcasts. + +Setting both KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST and +KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST will fail with an EINVAL error. + 7.8 KVM_CAP_S390_USER_INSTR0 ---------------------------- diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 48598d017d6f..4a6d94dc7a2a 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1229,6 +1229,12 @@ enum kvm_irqchip_mode { KVM_IRQCHIP_SPLIT, /* created with KVM_CAP_SPLIT_IRQCHIP */ }; +enum kvm_suppress_eoi_broadcast_mode { + KVM_SUPPRESS_EOI_BROADCAST_QUIRKED, /* Legacy behavior */ + KVM_SUPPRESS_EOI_BROADCAST_ENABLED, /* Enable Suppress EOI broadcast */ + KVM_SUPPRESS_EOI_BROADCAST_DISABLED /* Disable Suppress EOI broadcast */ +}; + struct kvm_x86_msr_filter { u8 count; bool default_allow:1; @@ -1480,6 +1486,7 @@ struct kvm_arch { bool x2apic_format; bool x2apic_broadcast_quirk_disabled; + enum kvm_suppress_eoi_broadcast_mode suppress_eoi_broadcast_mode; bool has_mapped_host_mmio; bool guest_can_read_msr_platform_info; diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index d420c9c066d4..d30241429fa8 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -913,8 +913,10 @@ struct kvm_sev_snp_launch_finish { __u64 pad1[4]; }; -#define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) -#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) +#define KVM_X2APIC_API_USE_32BIT_IDS (_BITULL(0)) +#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (_BITULL(1)) +#define KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST (_BITULL(2)) +#define KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST (_BITULL(3)) struct kvm_hyperv_eventfd { __u32 conn_id; diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 2c24fd8d815f..36a5af218802 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -107,21 +107,31 @@ bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector) bool kvm_lapic_advertise_suppress_eoi_broadcast(struct kvm *kvm) { - /* - * The default in-kernel I/O APIC emulates the 82093AA and does not - * implement an EOI register. Some guests (e.g. Windows with the - * Hyper-V role enabled) disable LAPIC EOI broadcast without checking - * the I/O APIC version, which can cause level-triggered interrupts to - * never be EOI'd. - * - * To avoid this, KVM must not advertise Suppress EOI Broadcast support - * when using the default in-kernel I/O APIC. - * - * Historically, in split IRQCHIP mode, KVM always advertised Suppress - * EOI Broadcast support but did not actually suppress EOIs, resulting - * in quirky behavior. - */ - return !ioapic_in_kernel(kvm); + switch (kvm->arch.suppress_eoi_broadcast_mode) { + case KVM_SUPPRESS_EOI_BROADCAST_ENABLED: + return true; + case KVM_SUPPRESS_EOI_BROADCAST_DISABLED: + return false; + case KVM_SUPPRESS_EOI_BROADCAST_QUIRKED: + /* + * The default in-kernel I/O APIC emulates the 82093AA and does not + * implement an EOI register. Some guests (e.g. Windows with the + * Hyper-V role enabled) disable LAPIC EOI broadcast without + * checking the I/O APIC version, which can cause level-triggered + * interrupts to never be EOI'd. + * + * To avoid this, KVM must not advertise Suppress EOI Broadcast + * support when using the default in-kernel I/O APIC. + * + * Historically, in split IRQCHIP mode, KVM always advertised + * Suppress EOI Broadcast support but did not actually suppress + * EOIs, resulting in quirky behavior. + */ + return !ioapic_in_kernel(kvm); + default: + WARN_ON_ONCE(1); + return false; + } } bool kvm_lapic_respect_suppress_eoi_broadcast(struct kvm *kvm) @@ -129,13 +139,25 @@ bool kvm_lapic_respect_suppress_eoi_broadcast(struct kvm *kvm) /* * Returns true if KVM should honor the guest's request to suppress EOI * broadcasts, i.e. actually implement Suppress EOI Broadcast. - * - * Historically, in split IRQCHIP mode, KVM ignored the suppress EOI - * broadcast bit set by the guest and broadcasts EOIs to the userspace - * I/O APIC. For In-kernel I/O APIC, the support itself is not - * advertised, but if bit was set by the guest, it was respected. */ - return ioapic_in_kernel(kvm); + switch (kvm->arch.suppress_eoi_broadcast_mode) { + case KVM_SUPPRESS_EOI_BROADCAST_ENABLED: + return true; + case KVM_SUPPRESS_EOI_BROADCAST_DISABLED: + return false; + case KVM_SUPPRESS_EOI_BROADCAST_QUIRKED: + /* + * Historically, in split IRQCHIP mode, KVM ignored the suppress + * EOI broadcast bit set by the guest and broadcasts EOIs to the + * userspace I/O APIC. For In-kernel I/O APIC, the support itself + * is not advertised, but if bit was set by the guest, it was + * respected. + */ + return ioapic_in_kernel(kvm); + default: + WARN_ON_ONCE(1); + return false; + } } __read_mostly DEFINE_STATIC_KEY_FALSE(kvm_has_noapic_vcpu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c9c2aa6f4705..5d56b0384dcc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -121,8 +121,10 @@ static u64 __read_mostly efer_reserved_bits = ~((u64)EFER_SCE); #define KVM_CAP_PMU_VALID_MASK KVM_PMU_CAP_DISABLE -#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_IDS | \ - KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK) +#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_IDS | \ + KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK | \ + KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST | \ + KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST) static void update_cr8_intercept(struct kvm_vcpu *vcpu); static void process_nmi(struct kvm_vcpu *vcpu); @@ -6778,11 +6780,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->args[0] & ~KVM_X2APIC_API_VALID_FLAGS) break; + if ((cap->args[0] & KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST) && + (cap->args[0] & KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST)) + break; + if (cap->args[0] & KVM_X2APIC_API_USE_32BIT_IDS) kvm->arch.x2apic_format = true; if (cap->args[0] & KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK) kvm->arch.x2apic_broadcast_quirk_disabled = true; + if (cap->args[0] & KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST) + kvm->arch.suppress_eoi_broadcast_mode = KVM_SUPPRESS_EOI_BROADCAST_ENABLED; + if (cap->args[0] & KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST) + kvm->arch.suppress_eoi_broadcast_mode = KVM_SUPPRESS_EOI_BROADCAST_DISABLED; + r = 0; break; case KVM_CAP_X86_DISABLE_EXITS: -- 2.39.3

4 days

[PATCH v2 0/3] PCI: dwc: Fix missing iATU setup when ECAM is enabled

by Krishna Chaitanya Chundru

When ECAM is enabled, the driver skipped calling dw_pcie_iatu_setup() before configuring ECAM iATU entries. This left IO and MEM outbound windows unprogrammed, resulting in broken IO transactions. Additionally, dw_pcie_config_ecam_iatu() was only called during host initialization, so ECAM-related iATU entries were not restored after suspend/resume, leading to failures in configuration space access. To resolve these issues, the ECAM iATU configuration is moved into dw_pcie_setup_rc(). At the same time, dw_pcie_iatu_setup() is invoked when ECAM is enabled. Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru(a)oss.qualcomm.com> --- Changes in v2: - Fixed the index 0 of the ATU window skipping. - Keep the ob_atu_index in dw_pcie instead of dw_pcie_rp & couple of nitpicks (Bjorn). - Link to v1: https://lore.kernel.org/r/20251203-ecam_io_fix-v1-0-5cc3d3769c18@oss.qualco… --- Krishna Chaitanya Chundru (3): PCI: dwc: Fix skipped index 0 in outbound ATU setup PCI: dwc: Correct iATU index increment for MSG TLP region PCI: dwc: Fix missing iATU setup when ECAM is enabled drivers/pci/controller/dwc/pcie-designware-host.c | 53 ++++++++++++++--------- drivers/pci/controller/dwc/pcie-designware.c | 3 ++ drivers/pci/controller/dwc/pcie-designware.h | 2 +- 3 files changed, 37 insertions(+), 21 deletions(-) --- base-commit: 3f9f0252130e7dd60d41be0802bf58f6471c691d change-id: 20251203-ecam_io_fix-6e060fecd3b8 Best regards, -- Krishna Chaitanya Chundru <krishna.chundru(a)oss.qualcomm.com>

4 days

[PATCH] misc: bcm-vk: validate entry_size before memcpy_fromio()

by Guangshuo Li

The driver trusts the 'num' and 'entry_size' fields read from BAR2 and uses them directly to compute the length for memcpy_fromio() without any bounds checking. If these fields get corrupted or otherwise contain invalid values, num * entry_size can exceed the size of proc_mon_info.entries and lead to a potential out-of-bounds write. Add validation for 'entry_size' by ensuring it is non-zero and that num * entry_size does not exceed the size of proc_mon_info.entries. Fixes: ff428d052b3b ("misc: bcm-vk: add get_card_info, peerlog_info, and proc_mon_info") Cc: stable(a)vger.kernel.org Signed-off-by: Guangshuo Li <lgs201920130244(a)gmail.com> --- drivers/misc/bcm-vk/bcm_vk_dev.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/misc/bcm-vk/bcm_vk_dev.c b/drivers/misc/bcm-vk/bcm_vk_dev.c index a16b99bdaa13..a4a74c10f02b 100644 --- a/drivers/misc/bcm-vk/bcm_vk_dev.c +++ b/drivers/misc/bcm-vk/bcm_vk_dev.c @@ -439,6 +439,7 @@ static void bcm_vk_get_proc_mon_info(struct bcm_vk *vk) struct device *dev = &vk->pdev->dev; struct bcm_vk_proc_mon_info *mon = &vk->proc_mon_info; u32 num, entry_size, offset, buf_size; + size_t max_bytes; u8 *dst; /* calculate offset which is based on peerlog offset */ @@ -458,6 +459,9 @@ static void bcm_vk_get_proc_mon_info(struct bcm_vk *vk) num, BCM_VK_PROC_MON_MAX); return; } + if (!entry_size || (size_t)num > max_bytes / entry_size) { + return; + } mon->num = num; mon->entry_size = entry_size; -- 2.43.0

4 days, 1 hour

[PATCH 0/7] arm64: dts: rockchip: Sound fixes and additions on RK3576 boards

by Alexey Charkov

Here are some device tree updates to improve sound output on RK3576 boards. The first two patches fix analog audio output on FriendlyElec NanoPi M5, as it doesn't work with the current device tree. The third one is purely cosmetic, to present a more user-friendly sound card name to the userspace on NanoPi M5. The rest add new functionality: HDMI sound output on three boards that didn't enable it, and analog sound on RK3576 EVB1. Signed-off-by: Alexey Charkov <alchark(a)gmail.com> --- Alexey Charkov (7): arm64: dts: rockchip: Fix headphones widget name on NanoPi M5 arm64: dts: rockchip: Configure MCLK for analog sound on NanoPi M5 arm64: dts: rockchip: Use a readable audio card name on NanoPi M5 arm64: dts: rockchip: Enable HDMI sound on FriendlyElec NanoPi M5 arm64: dts: rockchip: Enable HDMI sound on Luckfox Core3576 arm64: dts: rockchip: Enable HDMI sound on RK3576 EVB1 arm64: dts: rockchip: Enable analog sound on RK3576 EVB1 arch/arm64/boot/dts/rockchip/rk3576-evb1-v10.dts | 107 +++++++++++++++++++++ .../boot/dts/rockchip/rk3576-luckfox-core3576.dtsi | 8 ++ arch/arm64/boot/dts/rockchip/rk3576-nanopi-m5.dts | 22 ++++- 3 files changed, 132 insertions(+), 5 deletions(-) --- base-commit: cc3aa43b44bdb43dfbac0fcb51c56594a11338a8 change-id: 20251222-rk3576-sound-0c26e3b16924 Best regards, -- Alexey Charkov <alchark(a)gmail.com>

4 days, 1 hour

[PATCH] arm64: dts: imx95: correct I3C2 pclk to IMX95_CLK_BUSWAKEUP

by Carlos Song

I3C2 is in WAKEUP domain. Its pclk should be IMX95_CLK_BUSWAKEUP. Fixes: 969497ebefcf ("arm64: dts: imx95: Add i3c1 and i3c2") Signed-off-by: Carlos Song <carlos.song(a)nxp.com> Cc: <stable(a)vger.kernel.org> --- arch/arm64/boot/dts/freescale/imx95.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/boot/dts/freescale/imx95.dtsi b/arch/arm64/boot/dts/freescale/imx95.dtsi index e45014d50abe..a4d854817559 100644 --- a/arch/arm64/boot/dts/freescale/imx95.dtsi +++ b/arch/arm64/boot/dts/freescale/imx95.dtsi @@ -828,7 +828,7 @@ i3c2: i3c@42520000 { interrupts = <GIC_SPI 57 IRQ_TYPE_LEVEL_HIGH>; #address-cells = <3>; #size-cells = <0>; - clocks = <&scmi_clk IMX95_CLK_BUSAON>, + clocks = <&scmi_clk IMX95_CLK_BUSWAKEUP>, <&scmi_clk IMX95_CLK_I3C2SLOW>; clock-names = "pclk", "fast_clk"; status = "disabled"; -- 2.34.1

4 days, 3 hours

[PATCH] x86/kexec: Add a sanity check on previous kernel's ima kexec buffer

by Harshit Mogalapalli

When the second-stage kernel is booted via kexec with a limiting command line such as "mem=<size>", the physical range that contains the carried over IMA measurement list may fall outside the truncated RAM leading to a kernel panic. BUG: unable to handle page fault for address: ffff97793ff47000 RIP: ima_restore_measurement_list+0xdc/0x45a #PF: error_code(0x0000) – not-present page Other architectures already validate the range with page_is_ram(), as done in commit: cbf9c4b9617b ("of: check previous kernel's ima-kexec-buffer against memory bounds") do a similar check on x86. Cc: stable(a)vger.kernel.org Fixes: b69a2afd5afc ("x86/kexec: Carry forward IMA measurement log on kexec") Reported-by: Paul Webb <paul.x.webb(a)oracle.com> Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli(a)oracle.com> --- Have tested the kexec for x86 kernel with IMA_KEXEC enabled and the above patch works good. Paul initially reported this on 6.12 kernel but I was able to reproduce this on 6.18, so I tried replicating how this was fixed in drivers/of/kexec.c --- arch/x86/kernel/setup.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 1b2edd07a3e1..fcef197d180e 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -439,9 +439,23 @@ int __init ima_free_kexec_buffer(void) int __init ima_get_kexec_buffer(void **addr, size_t *size) { + unsigned long start_pfn, end_pfn; + if (!ima_kexec_buffer_size) return -ENOENT; + /* + * Calculate the PFNs for the buffer and ensure + * they are with in addressable memory. + */ + start_pfn = PFN_DOWN(ima_kexec_buffer_phys); + end_pfn = PFN_DOWN(ima_kexec_buffer_phys + ima_kexec_buffer_size - 1); + if (!pfn_range_is_mapped(start_pfn, end_pfn)) { + pr_warn("IMA buffer at 0x%llx, size = 0x%zx beyond memory\n", + ima_kexec_buffer_phys, ima_kexec_buffer_size); + return -EINVAL; + } + *addr = __va(ima_kexec_buffer_phys); *size = ima_kexec_buffer_size; -- 2.50.1

4 days, 3 hours

[PATCH 6.6 0/2] fix do_softirq_post_smp_call_flush warnings caused by NET_RX_SOFTIRQ

by wen.yang＠linux.dev

From: Wen Yang <wen.yang(a)linux.dev> do_softirq_post_smp_call_flush() on PREEMPT_RT kernels carries a WARN_ON_ONCE() for any SOFTIRQ being raised from an SMP-call-function. Since do_softirq_post_smp_call_flush() is called with preempt disabled, raising a SOFTIRQ during flush_smp_call_function_queue() can lead to longer preempt disabled sections. RPS distributes network processing load across CPUs by enqueuing packets on a remote CPU's backlog and raising NET_RX_SOFTIRQ to process them. The following patches fixes this issue. Sebastian Andrzej Siewior (2): net: Remove conditional threaded-NAPI wakeup based on task state. net: Allow to use SMP threads for backlog NAPI. net/core/dev.c | 162 +++++++++++++++++++++++++++++++++++-------------- 1 file changed, 115 insertions(+), 47 deletions(-) -- 2.25.1

4 days, 3 hours

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