From: Laibin Qiu qiulaibin@huawei.com
hulk inclusion category: bugfix bugzilla: 185779, https://gitee.com/openeuler/kernel/issues/I4WFIY CVE: NA
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1.In current process, all bio will set the BIO_THROTTLED flag after __blk_throtl_bio().
2.If bio needs to be throttled, it will start the timer and stop submit bio directly. Bio will submit in blk_throtl_dispatch_work_fn() when the timer expires.But in the current process, if bio is throttled. The BIO_THROTTLED will be set to bio after timer start. If the bio has been completed, it may cause use-after-free blow.
BUG: KASAN: use-after-free in blk_throtl_bio+0x12f0/0x2c70 Read of size 2 at addr ffff88801b8902d4 by task fio/26380
dump_stack+0x9b/0xce print_address_description.constprop.6+0x3e/0x60 kasan_report.cold.9+0x22/0x3a blk_throtl_bio+0x12f0/0x2c70 submit_bio_checks+0x701/0x1550 submit_bio_noacct+0x83/0xc80 submit_bio+0xa7/0x330 mpage_readahead+0x380/0x500 read_pages+0x1c1/0xbf0 page_cache_ra_unbounded+0x471/0x6f0 do_page_cache_ra+0xda/0x110 ondemand_readahead+0x442/0xae0 page_cache_async_ra+0x210/0x300 generic_file_buffered_read+0x4d9/0x2130 generic_file_read_iter+0x315/0x490 blkdev_read_iter+0x113/0x1b0 aio_read+0x2ad/0x450 io_submit_one+0xc8e/0x1d60 __se_sys_io_submit+0x125/0x350 do_syscall_64+0x2d/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Allocated by task 26380: kasan_save_stack+0x19/0x40 __kasan_kmalloc.constprop.2+0xc1/0xd0 kmem_cache_alloc+0x146/0x440 mempool_alloc+0x125/0x2f0 bio_alloc_bioset+0x353/0x590 mpage_alloc+0x3b/0x240 do_mpage_readpage+0xddf/0x1ef0 mpage_readahead+0x264/0x500 read_pages+0x1c1/0xbf0 page_cache_ra_unbounded+0x471/0x6f0 do_page_cache_ra+0xda/0x110 ondemand_readahead+0x442/0xae0 page_cache_async_ra+0x210/0x300 generic_file_buffered_read+0x4d9/0x2130 generic_file_read_iter+0x315/0x490 blkdev_read_iter+0x113/0x1b0 aio_read+0x2ad/0x450 io_submit_one+0xc8e/0x1d60 __se_sys_io_submit+0x125/0x350 do_syscall_64+0x2d/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 0: kasan_save_stack+0x19/0x40 kasan_set_track+0x1c/0x30 kasan_set_free_info+0x1b/0x30 __kasan_slab_free+0x111/0x160 kmem_cache_free+0x94/0x460 mempool_free+0xd6/0x320 bio_free+0xe0/0x130 bio_put+0xab/0xe0 bio_endio+0x3a6/0x5d0 blk_update_request+0x590/0x1370 scsi_end_request+0x7d/0x400 scsi_io_completion+0x1aa/0xe50 scsi_softirq_done+0x11b/0x240 blk_mq_complete_request+0xd4/0x120 scsi_mq_done+0xf0/0x200 virtscsi_vq_done+0xbc/0x150 vring_interrupt+0x179/0x390 __handle_irq_event_percpu+0xf7/0x490 handle_irq_event_percpu+0x7b/0x160 handle_irq_event+0xcc/0x170 handle_edge_irq+0x215/0xb20 common_interrupt+0x60/0x120 asm_common_interrupt+0x1e/0x40
Fix this by move BIO_THROTTLED set into the queue_lock.
Signed-off-by: Laibin Qiu qiulaibin@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- block/blk-throttle.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 942776a10599..95a13da1f343 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2266,13 +2266,16 @@ bool blk_throtl_bio(struct bio *bio) struct throtl_service_queue *sq; bool rw = bio_data_dir(bio); bool throttled = false; + bool locked = true; struct throtl_data *td = tg->td;
rcu_read_lock();
/* see throtl_charge_bio() */ - if (bio_flagged(bio, BIO_THROTTLED)) + if (bio_flagged(bio, BIO_THROTTLED)) { + locked = false; goto out; + }
if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) { blkg_rwstat_add(&tg->stat_bytes, bio->bi_opf, @@ -2280,8 +2283,10 @@ bool blk_throtl_bio(struct bio *bio) blkg_rwstat_add(&tg->stat_ios, bio->bi_opf, 1); }
- if (!tg->has_rules[rw]) + if (!tg->has_rules[rw]) { + locked = false; goto out; + }
spin_lock_irq(&q->queue_lock);
@@ -2336,7 +2341,7 @@ bool blk_throtl_bio(struct bio *bio) sq = sq->parent_sq; tg = sq_to_tg(sq); if (!tg) - goto out_unlock; + goto out; }
/* out-of-limit, queue to @tg */ @@ -2364,8 +2369,6 @@ bool blk_throtl_bio(struct bio *bio) throtl_schedule_next_dispatch(tg->service_queue.parent_sq, true); }
-out_unlock: - spin_unlock_irq(&q->queue_lock); out: bio_set_flag(bio, BIO_THROTTLED);
@@ -2373,6 +2376,9 @@ bool blk_throtl_bio(struct bio *bio) if (throttled || !td->track_bio_latency) bio->bi_issue.value |= BIO_ISSUE_THROTL_SKIP_LATENCY; #endif + if (locked) + spin_unlock_irq(&q->queue_lock); + rcu_read_unlock(); return throttled; }