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| author | Tejun Heo <tj@kernel.org> | 2026-05-07 11:05:31 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-05-07 11:05:50 -1000 |
| commit | 4616a9c36be7e2e051ef53b0e8fd729da0277abf (patch) | |
| tree | 46deb695c6538e2c9c7055f467e66d6f810e7ee2 /kernel | |
| parent | b34c82777a2c0648ee053595f4b290fd5249b093 (diff) | |
| download | linux-4616a9c36be7e2e051ef53b0e8fd729da0277abf.tar.gz linux-4616a9c36be7e2e051ef53b0e8fd729da0277abf.zip | |
sched_ext: Move scx_error() out of scx_link_sched()'s lock region
scx_link_sched() holds scx_sched_lock. The scx_error() calls inside take the
same lock through scx_claim_exit() and deadlock. Move them out of the guard.
Fixes: 6b4576b09714 ("sched_ext: Reject sub-sched attachment to a disabled parent")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 3f0d8aeaed81..7d367c140a36 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -5585,10 +5585,12 @@ static void refresh_watchdog(void) static s32 scx_link_sched(struct scx_sched *sch) { + const char *err_msg; + s32 ret = 0; + scoped_guard(raw_spinlock_irq, &scx_sched_lock) { #ifdef CONFIG_EXT_SUB_SCHED struct scx_sched *parent = scx_parent(sch); - s32 ret; if (parent) { /* @@ -5598,15 +5600,16 @@ static s32 scx_link_sched(struct scx_sched *sch) * parent can shoot us down. */ if (atomic_read(&parent->exit_kind) != SCX_EXIT_NONE) { - scx_error(sch, "parent disabled"); - return -ENOENT; + err_msg = "parent disabled"; + ret = -ENOENT; + break; } ret = rhashtable_lookup_insert_fast(&scx_sched_hash, &sch->hash_node, scx_sched_hash_params); if (ret) { - scx_error(sch, "failed to insert into scx_sched_hash (%d)", ret); - return ret; + err_msg = "failed to insert into scx_sched_hash"; + break; } list_add_tail(&sch->sibling, &parent->children); @@ -5616,6 +5619,15 @@ static s32 scx_link_sched(struct scx_sched *sch) list_add_tail_rcu(&sch->all, &scx_sched_all); } + /* + * scx_error() takes scx_sched_lock via scx_claim_exit(), so it must run after + * the guard above is released. + */ + if (ret) { + scx_error(sch, "%s (%d)", err_msg, ret); + return ret; + } + refresh_watchdog(); return 0; } |