This was caught during QA test: BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:942 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 243401, name: sed INFO: lockdep is turned off. Preemption disabled at: [<ffffffff89b26268>] blk_cgroup_bio_start+0x28/0xd0 CPU: 2 PID: 243401 Comm: sed Kdump: loaded Not tainted 4.18.0-353.rt7.138.el8.x86_64+debug #1 Hardware name: HP ProLiant DL380 Gen9, BIOS P89 05/06/2015 Call Trace: dump_stack+0x5c/0x80 ___might_sleep.cold.89+0xf5/0x109 rt_spin_lock+0x3e/0xd0 ? __blk_add_trace+0x428/0x4b0 __blk_add_trace+0x428/0x4b0 blk_add_trace_bio+0x16e/0x1c0 generic_make_request_checks+0x7e8/0x8c0 generic_make_request+0x3c/0x420 ? membarrier_private_expedited+0xd0/0x2b0 ? lock_release+0x1ca/0x450 ? submit_bio+0x3c/0x160 ? _raw_spin_unlock_irqrestore+0x3c/0x80 submit_bio+0x3c/0x160 ? rt_mutex_futex_unlock+0x66/0xa0 iomap_submit_ioend.isra.36+0x4a/0x70 xfs_vm_writepages+0x65/0x90 [xfs] do_writepages+0x41/0xe0 ? rt_mutex_futex_unlock+0x66/0xa0 __filemap_fdatawrite_range+0xce/0x110 xfs_release+0x11c/0x160 [xfs] __fput+0xd5/0x270 task_work_run+0xa1/0xd0 exit_to_usermode_loop+0x14d/0x160 do_syscall_64+0x23b/0x240 entry_SYSCALL_64_after_hwframe+0x6a/0xdf We replace the get/put_cpu() call by get/put_cpu_light to avoid this bug. Signed-off-by: Wander Lairson Costa <wander@xxxxxxxxxx> --- block/blk-cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 663aabfeba18..0a532bb3003c 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1911,7 +1911,7 @@ void blk_cgroup_bio_start(struct bio *bio) struct blkg_iostat_set *bis; unsigned long flags; - cpu = get_cpu(); + cpu = get_cpu_light(); bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu); flags = u64_stats_update_begin_irqsave(&bis->sync); @@ -1928,7 +1928,7 @@ void blk_cgroup_bio_start(struct bio *bio) u64_stats_update_end_irqrestore(&bis->sync, flags); if (cgroup_subsys_on_dfl(io_cgrp_subsys)) cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu); - put_cpu(); + put_cpu_light(); } static int __init blkcg_init(void) -- 2.27.0
