diff options
| author | John Stultz <jstultz@google.com> | 2026-03-24 19:13:20 +0000 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-04-03 14:23:39 +0200 |
| commit | 56f4b24267a643b0b9ab73f09feaaabfee5a37ae (patch) | |
| tree | 1c13c7cd7be26496fdbf028de09b49c47585647e /kernel | |
| parent | fa4a1ff8ab235a308d8c983827657a69649185fd (diff) | |
sched: Fix modifying donor->blocked on without proper locking
Introduce an action enum in find_proxy_task() which allows
us to handle work needed to be done outside the mutex.wait_lock
and task.blocked_lock guard scopes.
This ensures proper locking when we clear the donor's blocked_on
pointer in proxy_deactivate(), and the switch statement will be
useful as we add more cases to handle later in this series.
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://patch.msgid.link/20260324191337.1841376-6-jstultz@google.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1913dbc68eb9..bf4338f71667 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6568,7 +6568,7 @@ static struct task_struct *proxy_deactivate(struct rq *rq, struct task_struct *d * as unblocked, as we aren't doing proxy-migrations * yet (more logic will be needed then). */ - donor->blocked_on = NULL; + clear_task_blocked_on(donor, NULL); } return NULL; } @@ -6592,6 +6592,7 @@ static struct task_struct *proxy_deactivate(struct rq *rq, struct task_struct *d static struct task_struct * find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) { + enum { FOUND, DEACTIVATE_DONOR } action = FOUND; struct task_struct *owner = NULL; int this_cpu = cpu_of(rq); struct task_struct *p; @@ -6625,12 +6626,14 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) if (!READ_ONCE(owner->on_rq) || owner->se.sched_delayed) { /* XXX Don't handle blocked owners/delayed dequeue yet */ - return proxy_deactivate(rq, donor); + action = DEACTIVATE_DONOR; + break; } if (task_cpu(owner) != this_cpu) { /* XXX Don't handle migrations yet */ - return proxy_deactivate(rq, donor); + action = DEACTIVATE_DONOR; + break; } if (task_on_rq_migrating(owner)) { @@ -6688,6 +6691,13 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) */ } + /* Handle actions we need to do outside of the guard() scope */ + switch (action) { + case DEACTIVATE_DONOR: + return proxy_deactivate(rq, donor); + case FOUND: + /* fallthrough */; + } WARN_ON_ONCE(owner && !owner->on_rq); return owner; } |