From: Zhang Wensheng <zhangwensheng5@xxxxxxxxxx> [ Upstream commit ab552fcb17cc9e4afe0e4ac4df95fc7b30e8490a ] KASAN reports a use-after-free report when doing normal scsi-mq test [69832.239032] ================================================================== [69832.241810] BUG: KASAN: use-after-free in bfq_dispatch_request+0x1045/0x44b0 [69832.243267] Read of size 8 at addr ffff88802622ba88 by task kworker/3:1H/155 [69832.244656] [69832.245007] CPU: 3 PID: 155 Comm: kworker/3:1H Not tainted 5.10.0-10295-g576c6382529e #8 [69832.246626] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [69832.249069] Workqueue: kblockd blk_mq_run_work_fn [69832.250022] Call Trace: [69832.250541] dump_stack+0x9b/0xce [69832.251232] ? bfq_dispatch_request+0x1045/0x44b0 [69832.252243] print_address_description.constprop.6+0x3e/0x60 [69832.253381] ? __cpuidle_text_end+0x5/0x5 [69832.254211] ? vprintk_func+0x6b/0x120 [69832.254994] ? bfq_dispatch_request+0x1045/0x44b0 [69832.255952] ? bfq_dispatch_request+0x1045/0x44b0 [69832.256914] kasan_report.cold.9+0x22/0x3a [69832.257753] ? bfq_dispatch_request+0x1045/0x44b0 [69832.258755] check_memory_region+0x1c1/0x1e0 [69832.260248] bfq_dispatch_request+0x1045/0x44b0 [69832.261181] ? bfq_bfqq_expire+0x2440/0x2440 [69832.262032] ? blk_mq_delay_run_hw_queues+0xf9/0x170 [69832.263022] __blk_mq_do_dispatch_sched+0x52f/0x830 [69832.264011] ? blk_mq_sched_request_inserted+0x100/0x100 [69832.265101] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [69832.266206] ? blk_mq_do_dispatch_ctx+0x570/0x570 [69832.267147] ? __switch_to+0x5f4/0xee0 [69832.267898] blk_mq_sched_dispatch_requests+0xdf/0x140 [69832.268946] __blk_mq_run_hw_queue+0xc0/0x270 [69832.269840] blk_mq_run_work_fn+0x51/0x60 [69832.278170] process_one_work+0x6d4/0xfe0 [69832.278984] worker_thread+0x91/0xc80 [69832.279726] ? __kthread_parkme+0xb0/0x110 [69832.280554] ? process_one_work+0xfe0/0xfe0 [69832.281414] kthread+0x32d/0x3f0 [69832.282082] ? kthread_park+0x170/0x170 [69832.282849] ret_from_fork+0x1f/0x30 [69832.283573] [69832.283886] Allocated by task 7725: [69832.284599] kasan_save_stack+0x19/0x40 [69832.285385] __kasan_kmalloc.constprop.2+0xc1/0xd0 [69832.286350] kmem_cache_alloc_node+0x13f/0x460 [69832.287237] bfq_get_queue+0x3d4/0x1140 [69832.287993] bfq_get_bfqq_handle_split+0x103/0x510 [69832.289015] bfq_init_rq+0x337/0x2d50 [69832.289749] bfq_insert_requests+0x304/0x4e10 [69832.290634] blk_mq_sched_insert_requests+0x13e/0x390 [69832.291629] blk_mq_flush_plug_list+0x4b4/0x760 [69832.292538] blk_flush_plug_list+0x2c5/0x480 [69832.293392] io_schedule_prepare+0xb2/0xd0 [69832.294209] io_schedule_timeout+0x13/0x80 [69832.295014] wait_for_common_io.constprop.1+0x13c/0x270 [69832.296137] submit_bio_wait+0x103/0x1a0 [69832.296932] blkdev_issue_discard+0xe6/0x160 [69832.297794] blk_ioctl_discard+0x219/0x290 [69832.298614] blkdev_common_ioctl+0x50a/0x1750 [69832.304715] blkdev_ioctl+0x470/0x600 [69832.305474] block_ioctl+0xde/0x120 [69832.306232] vfs_ioctl+0x6c/0xc0 [69832.306877] __se_sys_ioctl+0x90/0xa0 [69832.307629] do_syscall_64+0x2d/0x40 [69832.308362] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [69832.309382] [69832.309701] Freed by task 155: [69832.310328] kasan_save_stack+0x19/0x40 [69832.311121] kasan_set_track+0x1c/0x30 [69832.311868] kasan_set_free_info+0x1b/0x30 [69832.312699] __kasan_slab_free+0x111/0x160 [69832.313524] kmem_cache_free+0x94/0x460 [69832.314367] bfq_put_queue+0x582/0x940 [69832.315112] __bfq_bfqd_reset_in_service+0x166/0x1d0 [69832.317275] bfq_bfqq_expire+0xb27/0x2440 [69832.318084] bfq_dispatch_request+0x697/0x44b0 [69832.318991] __blk_mq_do_dispatch_sched+0x52f/0x830 [69832.319984] __blk_mq_sched_dispatch_requests+0x398/0x4f0 [69832.321087] blk_mq_sched_dispatch_requests+0xdf/0x140 [69832.322225] __blk_mq_run_hw_queue+0xc0/0x270 [69832.323114] blk_mq_run_work_fn+0x51/0x60 [69832.323942] process_one_work+0x6d4/0xfe0 [69832.324772] worker_thread+0x91/0xc80 [69832.325518] kthread+0x32d/0x3f0 [69832.326205] ret_from_fork+0x1f/0x30 [69832.326932] [69832.338297] The buggy address belongs to the object at ffff88802622b968 [69832.338297] which belongs to the cache bfq_queue of size 512 [69832.340766] The buggy address is located 288 bytes inside of [69832.340766] 512-byte region [ffff88802622b968, ffff88802622bb68) [69832.343091] The buggy address belongs to the page: [69832.344097] page:ffffea0000988a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802622a528 pfn:0x26228 [69832.346214] head:ffffea0000988a00 order:2 compound_mapcount:0 compound_pincount:0 [69832.347719] flags: 0x1fffff80010200(slab|head) [69832.348625] raw: 001fffff80010200 ffffea0000dbac08 ffff888017a57650 ffff8880179fe840 [69832.354972] raw: ffff88802622a528 0000000000120008 00000001ffffffff 0000000000000000 [69832.356547] page dumped because: kasan: bad access detected [69832.357652] [69832.357970] Memory state around the buggy address: [69832.358926] ffff88802622b980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.360358] ffff88802622ba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.361810] >ffff88802622ba80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [69832.363273] ^ [69832.363975] ffff88802622bb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc [69832.375960] ffff88802622bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [69832.377405] ================================================================== In bfq_dispatch_requestfunction, it may have function call: bfq_dispatch_request __bfq_dispatch_request bfq_select_queue bfq_bfqq_expire __bfq_bfqd_reset_in_service bfq_put_queue kmem_cache_free In this function call, in_serv_queue has beed expired and meet the conditions to free. In the function bfq_dispatch_request, the address of in_serv_queue pointing to has been released. For getting the value of idle_timer_disabled, it will get flags value from the address which in_serv_queue pointing to, then the problem of use-after-free happens; Fix the problem by check in_serv_queue == bfqd->in_service_queue, to get the value of idle_timer_disabled if in_serve_queue is equel to bfqd->in_service_queue. If the space of in_serv_queue pointing has been released, this judge will aviod use-after-free problem. And if in_serv_queue may be expired or finished, the idle_timer_disabled will be false which would not give effects to bfq_update_dispatch_stats. Reported-by: Hulk Robot <hulkci@xxxxxxxxxx> Signed-off-by: Zhang Wensheng <zhangwensheng5@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220303070334.3020168-1-zhangwensheng5@xxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- block/bfq-iosched.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 11686e768401..dfd55037dc6f 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -4122,7 +4122,7 @@ static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) struct bfq_data *bfqd = hctx->queue->elevator->elevator_data; struct request *rq; struct bfq_queue *in_serv_queue; - bool waiting_rq, idle_timer_disabled; + bool waiting_rq, idle_timer_disabled = false; spin_lock_irq(&bfqd->lock); @@ -4130,14 +4130,15 @@ static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) waiting_rq = in_serv_queue && bfq_bfqq_wait_request(in_serv_queue); rq = __bfq_dispatch_request(hctx); - - idle_timer_disabled = - waiting_rq && !bfq_bfqq_wait_request(in_serv_queue); + if (in_serv_queue == bfqd->in_service_queue) { + idle_timer_disabled = + waiting_rq && !bfq_bfqq_wait_request(in_serv_queue); + } spin_unlock_irq(&bfqd->lock); - - bfq_update_dispatch_stats(hctx->queue, rq, in_serv_queue, - idle_timer_disabled); + bfq_update_dispatch_stats(hctx->queue, rq, + idle_timer_disabled ? in_serv_queue : NULL, + idle_timer_disabled); return rq; } -- 2.34.1
