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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-10-29 16:35:40 -1000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-10-29 16:35:40 -1000 |
| commit | daa9f66fe194f672d2c94d879b6dad7035e03ebe (patch) | |
| tree | d2ae3065e809457070ccbaca15946275c8280abf /kernel | |
| parent | 7fbaacafbc55c56ca156a628a805f79a2cbe7103 (diff) | |
| parent | c31f2ee5cd7da3086eb4fbeef9f3afdc8e01d36b (diff) | |
Merge tag 'sched_ext-for-6.12-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext fixes from Tejun Heo:
- Instances of scx_ops_bypass() could race each other leading to
misbehavior. Fix by protecting the operation with a spinlock.
- selftest and userspace header fixes
* tag 'sched_ext-for-6.12-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
sched_ext: Fix enq_last_no_enq_fails selftest
sched_ext: Make cast_mask() inline
scx: Fix raciness in scx_ops_bypass()
scx: Fix exit selftest to use custom DSQ
sched_ext: Fix function pointer type mismatches in BPF selftests
selftests/sched_ext: add order-only dependency of runner.o on BPFOBJ
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 5900b06fd036..8b98ab2dca5a 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -862,7 +862,8 @@ static DEFINE_MUTEX(scx_ops_enable_mutex); DEFINE_STATIC_KEY_FALSE(__scx_ops_enabled); DEFINE_STATIC_PERCPU_RWSEM(scx_fork_rwsem); static atomic_t scx_ops_enable_state_var = ATOMIC_INIT(SCX_OPS_DISABLED); -static atomic_t scx_ops_bypass_depth = ATOMIC_INIT(0); +static int scx_ops_bypass_depth; +static DEFINE_RAW_SPINLOCK(__scx_ops_bypass_lock); static bool scx_ops_init_task_enabled; static bool scx_switching_all; DEFINE_STATIC_KEY_FALSE(__scx_switched_all); @@ -4298,18 +4299,20 @@ bool task_should_scx(struct task_struct *p) */ static void scx_ops_bypass(bool bypass) { - int depth, cpu; + int cpu; + unsigned long flags; + raw_spin_lock_irqsave(&__scx_ops_bypass_lock, flags); if (bypass) { - depth = atomic_inc_return(&scx_ops_bypass_depth); - WARN_ON_ONCE(depth <= 0); - if (depth != 1) - return; + scx_ops_bypass_depth++; + WARN_ON_ONCE(scx_ops_bypass_depth <= 0); + if (scx_ops_bypass_depth != 1) + goto unlock; } else { - depth = atomic_dec_return(&scx_ops_bypass_depth); - WARN_ON_ONCE(depth < 0); - if (depth != 0) - return; + scx_ops_bypass_depth--; + WARN_ON_ONCE(scx_ops_bypass_depth < 0); + if (scx_ops_bypass_depth != 0) + goto unlock; } /* @@ -4326,7 +4329,7 @@ static void scx_ops_bypass(bool bypass) struct rq_flags rf; struct task_struct *p, *n; - rq_lock_irqsave(rq, &rf); + rq_lock(rq, &rf); if (bypass) { WARN_ON_ONCE(rq->scx.flags & SCX_RQ_BYPASSING); @@ -4362,11 +4365,13 @@ static void scx_ops_bypass(bool bypass) sched_enq_and_set_task(&ctx); } - rq_unlock_irqrestore(rq, &rf); + rq_unlock(rq, &rf); /* resched to restore ticks and idle state */ resched_cpu(cpu); } +unlock: + raw_spin_unlock_irqrestore(&__scx_ops_bypass_lock, flags); } static void free_exit_info(struct scx_exit_info *ei) |