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authorMing Lei <ming.lei@redhat.com>2022-03-23 09:13:08 +0800
committerJens Axboe <axboe@kernel.dk>2022-03-22 19:52:23 -0600
commitd578c770c85233af592e54537f93f3831bde7e9a (patch)
tree71e81c4c1f35f73045b3ee42fbc75e8215a1ad3c /block
parent863a66cdb4df25fd146d9851c3289072298566d5 (diff)
block: avoid calling blkg_free() in atomic context
blkg_free() can currently be called in atomic context, either spin lock is held, or run in rcu callback. Meantime either request queue's release handler or ->pd_free_fn can sleep. Fix the issue by scheduling a work function for freeing blkcg_gq the instance. [ 148.553894] BUG: sleeping function called from invalid context at block/blk-sysfs.c:767 [ 148.557381] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/13 [ 148.560741] preempt_count: 101, expected: 0 [ 148.562577] RCU nest depth: 0, expected: 0 [ 148.564379] 1 lock held by swapper/13/0: [ 148.566127] #0: ffffffff82615f80 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire+0x0/0x1b [ 148.569640] Preemption disabled at: [ 148.569642] [<ffffffff8123f9c3>] ___slab_alloc+0x554/0x661 [ 148.573559] CPU: 13 PID: 0 Comm: swapper/13 Kdump: loaded Not tainted 5.17.0_up+ #110 [ 148.576834] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-1.fc33 04/01/2014 [ 148.579768] Call Trace: [ 148.580567] <IRQ> [ 148.581262] dump_stack_lvl+0x56/0x7c [ 148.582367] ? ___slab_alloc+0x554/0x661 [ 148.583526] __might_resched+0x1af/0x1c8 [ 148.584678] blk_release_queue+0x24/0x109 [ 148.585861] kobject_cleanup+0xc9/0xfe [ 148.586979] blkg_free+0x46/0x63 [ 148.587962] rcu_do_batch+0x1c5/0x3db [ 148.589057] rcu_core+0x14a/0x184 [ 148.590065] __do_softirq+0x14d/0x2c7 [ 148.591167] __irq_exit_rcu+0x7a/0xd4 [ 148.592264] sysvec_apic_timer_interrupt+0x82/0xa5 [ 148.593649] </IRQ> [ 148.594354] <TASK> [ 148.595058] asm_sysvec_apic_timer_interrupt+0x12/0x20 Cc: Tejun Heo <tj@kernel.org> Fixes: 0a9a25ca7843 ("block: let blkcg_gq grab request queue's refcnt") Reported-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/linux-block/20220322093322.GA27283@lst.de/ Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220323011308.2010380-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-cgroup.c32
1 files changed, 22 insertions, 10 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index d53b0d69dd73..6ed43fc0e6ab 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -65,19 +65,12 @@ static bool blkcg_policy_enabled(struct request_queue *q,
return pol && test_bit(pol->plid, q->blkcg_pols);
}
-/**
- * blkg_free - free a blkg
- * @blkg: blkg to free
- *
- * Free @blkg which may be partially allocated.
- */
-static void blkg_free(struct blkcg_gq *blkg)
+static void blkg_free_workfn(struct work_struct *work)
{
+ struct blkcg_gq *blkg = container_of(work, struct blkcg_gq,
+ free_work);
int i;
- if (!blkg)
- return;
-
for (i = 0; i < BLKCG_MAX_POLS; i++)
if (blkg->pd[i])
blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
@@ -89,6 +82,25 @@ static void blkg_free(struct blkcg_gq *blkg)
kfree(blkg);
}
+/**
+ * blkg_free - free a blkg
+ * @blkg: blkg to free
+ *
+ * Free @blkg which may be partially allocated.
+ */
+static void blkg_free(struct blkcg_gq *blkg)
+{
+ if (!blkg)
+ return;
+
+ /*
+ * Both ->pd_free_fn() and request queue's release handler may
+ * sleep, so free us by scheduling one work func
+ */
+ INIT_WORK(&blkg->free_work, blkg_free_workfn);
+ schedule_work(&blkg->free_work);
+}
+
static void __blkg_release(struct rcu_head *rcu)
{
struct blkcg_gq *blkg = container_of(rcu, struct blkcg_gq, rcu_head);