From 6f5ddde41069fcd1f0993ec76c9dbbf9d021fd4d Mon Sep 17 00:00:00 2001 From: Yanfei Xu Date: Wed, 15 Sep 2021 15:24:26 +0800 Subject: [PATCH] blkcg: fix memory leak in blk_iolatency_init BUG: memory leak unreferenced object 0xffff888129acdb80 (size 96): comm "syz-executor.1", pid 12661, jiffies 4294962682 (age 15.220s) hex dump (first 32 bytes): 20 47 c9 85 ff ff ff ff 20 d4 8e 29 81 88 ff ff G...... ..).... 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] kmalloc include/linux/slab.h:591 [inline] [] kzalloc include/linux/slab.h:721 [inline] [] blk_iolatency_init+0x28/0x190 block/blk-iolatency.c:724 [] blkcg_init_queue+0xb4/0x1c0 block/blk-cgroup.c:1185 [] blk_alloc_queue+0x22a/0x2e0 block/blk-core.c:566 [] blk_mq_init_queue_data block/blk-mq.c:3100 [inline] [] __blk_mq_alloc_disk+0x25/0xd0 block/blk-mq.c:3124 [] loop_add+0x1c3/0x360 drivers/block/loop.c:2344 [] loop_control_get_free drivers/block/loop.c:2501 [inline] [] loop_control_ioctl+0x17e/0x2e0 drivers/block/loop.c:2516 [] vfs_ioctl fs/ioctl.c:51 [inline] [] __do_sys_ioctl fs/ioctl.c:874 [inline] [] __se_sys_ioctl fs/ioctl.c:860 [inline] [] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:860 [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [] entry_SYSCALL_64_after_hwframe+0x44/0xae Once blk_throtl_init() queue init failed, blkcg_iolatency_exit() will not be invoked for cleanup. That leads a memory leak. Swap the blk_throtl_init() and blk_iolatency_init() calls can solve this. Reported-by: syzbot+01321b15cc98e6bf96d6@syzkaller.appspotmail.com Fixes: 19688d7f9592 (block/blk-cgroup: Swap the blk_throtl_init() and blk_iolatency_init() calls) Signed-off-by: Yanfei Xu Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20210915072426.4022924-1-yanfei.xu@windriver.com Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 3c88a79a319b..1ded4181a6de 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1182,10 +1182,6 @@ int blkcg_init_queue(struct request_queue *q) if (preloaded) radix_tree_preload_end(); - ret = blk_iolatency_init(q); - if (ret) - goto err_destroy_all; - ret = blk_ioprio_init(q); if (ret) goto err_destroy_all; @@ -1194,6 +1190,12 @@ int blkcg_init_queue(struct request_queue *q) if (ret) goto err_destroy_all; + ret = blk_iolatency_init(q); + if (ret) { + blk_throtl_exit(q); + goto err_destroy_all; + } + return 0; err_destroy_all: