From 06343b27411344fc542f4f3a643f8441aa35252d Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 8 May 2024 05:21:37 +0200 Subject: Adding debian version 4.19.260-1. Signed-off-by: Daniel Baumann --- ...ddress-a-race-resulting-in-double-enqueue.patch | 120 --------------------- 1 file changed, 120 deletions(-) delete mode 100644 debian/patches-rt/0324-tasklet-Address-a-race-resulting-in-double-enqueue.patch (limited to 'debian/patches-rt/0324-tasklet-Address-a-race-resulting-in-double-enqueue.patch') diff --git a/debian/patches-rt/0324-tasklet-Address-a-race-resulting-in-double-enqueue.patch b/debian/patches-rt/0324-tasklet-Address-a-race-resulting-in-double-enqueue.patch deleted file mode 100644 index 70a6d70cb..000000000 --- a/debian/patches-rt/0324-tasklet-Address-a-race-resulting-in-double-enqueue.patch +++ /dev/null @@ -1,120 +0,0 @@ -From f9bcdc9de0ced2b99b351e226344eb1c0246dd5c Mon Sep 17 00:00:00 2001 -From: Zhang Xiao -Date: Tue, 17 Mar 2020 12:47:43 +0100 -Subject: [PATCH 324/347] tasklet: Address a race resulting in double-enqueue -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz - -The kernel bugzilla has the following race condition reported: - -CPU0 CPU1 CPU2 ------------------------------------------------- -test_set SCHED - test_set RUN - if SCHED - add_list - raise - clear RUN - -test_set RUN -test_clear SCHED - ->func - test_set SCHED -tasklet_try_unlock ->0 -test_clear SCHED - test_set SCHED - ->func -tasklet_try_unlock ->1 - test_set RUN - if SCHED - add list - raise - clear RUN - test_set RUN - if SCHED - add list - raise - clear RUN - -As a result the tasklet is enqueued on both CPUs and run on both CPUs. Due -to the nature of the list used here, it is possible that further -(different) tasklets, which are enqueued after this double-enqueued -tasklet, are scheduled on CPU2 but invoked on CPU1. It is also possible -that these tasklets won't be invoked at all, because during the second -enqueue process the t->next pointer is set to NULL - dropping everything -from the list. - -This race will trigger one or two of the WARN_ON() in -tasklet_action_common(). -The problem is that the tasklet may be invoked multiple times and clear -SCHED bit on each invocation. This makes it possible to enqueue the -very same tasklet on different CPUs. - -Current RT-devel is using the upstream implementation which does not -re-run tasklets if they have SCHED set again and so it does not clear -the SCHED bit multiple times on a single invocation. - -Introduce the CHAINED flag. The tasklet will only be enqueued if the -CHAINED flag has been set successfully. -If it is possible to exchange the flags (CHAINED | RUN) -> 0 then the -tasklet won't be re-run. Otherwise the possible SCHED flag is removed -and the tasklet is re-run again. - -Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=61451 -Not-signed-off-by: Zhang Xiao -[bigeasy: patch description] -Signed-off-by: Sebastian Andrzej Siewior - -Signed-off-by: Tom Zanussi ---- - include/linux/interrupt.h | 5 ++++- - kernel/softirq.c | 6 +++++- - 2 files changed, 9 insertions(+), 2 deletions(-) - -diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h -index 97d9ba26915e..a3b5edb26bc5 100644 ---- a/include/linux/interrupt.h -+++ b/include/linux/interrupt.h -@@ -579,12 +579,15 @@ enum - { - TASKLET_STATE_SCHED, /* Tasklet is scheduled for execution */ - TASKLET_STATE_RUN, /* Tasklet is running (SMP only) */ -- TASKLET_STATE_PENDING /* Tasklet is pending */ -+ TASKLET_STATE_PENDING, /* Tasklet is pending */ -+ TASKLET_STATE_CHAINED /* Tasklet is chained */ - }; - - #define TASKLET_STATEF_SCHED (1 << TASKLET_STATE_SCHED) - #define TASKLET_STATEF_RUN (1 << TASKLET_STATE_RUN) - #define TASKLET_STATEF_PENDING (1 << TASKLET_STATE_PENDING) -+#define TASKLET_STATEF_CHAINED (1 << TASKLET_STATE_CHAINED) -+#define TASKLET_STATEF_RC (TASKLET_STATEF_RUN | TASKLET_STATEF_CHAINED) - - #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL) - static inline int tasklet_trylock(struct tasklet_struct *t) -diff --git a/kernel/softirq.c b/kernel/softirq.c -index 25bcf2f2714b..73dae64bfc9c 100644 ---- a/kernel/softirq.c -+++ b/kernel/softirq.c -@@ -947,6 +947,10 @@ static void __tasklet_schedule_common(struct tasklet_struct *t, - * is locked before adding it to the list. - */ - if (test_bit(TASKLET_STATE_SCHED, &t->state)) { -+ if (test_and_set_bit(TASKLET_STATE_CHAINED, &t->state)) { -+ tasklet_unlock(t); -+ return; -+ } - t->next = NULL; - *head->tail = t; - head->tail = &(t->next); -@@ -1040,7 +1044,7 @@ static void tasklet_action_common(struct softirq_action *a, - again: - t->func(t->data); - -- while (!tasklet_tryunlock(t)) { -+ while (cmpxchg(&t->state, TASKLET_STATEF_RC, 0) != TASKLET_STATEF_RC) { - /* - * If it got disabled meanwhile, bail out: - */ --- -2.36.1 - -- cgit v1.2.3