| From c3fc1f8d3c2f07f557c33f940349651959fcb753 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 20 Jul 2021 16:38:05 +0800 |
| Subject: io_uring: fix memleak in io_init_wq_offload() |
| |
| From: Yang Yingliang <yangyingliang@huawei.com> |
| |
| [ Upstream commit 362a9e65289284f36403058eea2462d0330c1f24 ] |
| |
| I got memory leak report when doing fuzz test: |
| |
| BUG: memory leak |
| unreferenced object 0xffff888107310a80 (size 96): |
| comm "syz-executor.6", pid 4610, jiffies 4295140240 (age 20.135s) |
| hex dump (first 32 bytes): |
| 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... |
| backtrace: |
| [<000000001974933b>] kmalloc include/linux/slab.h:591 [inline] |
| [<000000001974933b>] kzalloc include/linux/slab.h:721 [inline] |
| [<000000001974933b>] io_init_wq_offload fs/io_uring.c:7920 [inline] |
| [<000000001974933b>] io_uring_alloc_task_context+0x466/0x640 fs/io_uring.c:7955 |
| [<0000000039d0800d>] __io_uring_add_tctx_node+0x256/0x360 fs/io_uring.c:9016 |
| [<000000008482e78c>] io_uring_add_tctx_node fs/io_uring.c:9052 [inline] |
| [<000000008482e78c>] __do_sys_io_uring_enter fs/io_uring.c:9354 [inline] |
| [<000000008482e78c>] __se_sys_io_uring_enter fs/io_uring.c:9301 [inline] |
| [<000000008482e78c>] __x64_sys_io_uring_enter+0xabc/0xc20 fs/io_uring.c:9301 |
| [<00000000b875f18f>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] |
| [<00000000b875f18f>] do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80 |
| [<000000006b0a8484>] entry_SYSCALL_64_after_hwframe+0x44/0xae |
| |
| CPU0 CPU1 |
| io_uring_enter io_uring_enter |
| io_uring_add_tctx_node io_uring_add_tctx_node |
| __io_uring_add_tctx_node __io_uring_add_tctx_node |
| io_uring_alloc_task_context io_uring_alloc_task_context |
| io_init_wq_offload io_init_wq_offload |
| hash = kzalloc hash = kzalloc |
| ctx->hash_map = hash ctx->hash_map = hash <- one of the hash is leaked |
| |
| When calling io_uring_enter() in parallel, the 'hash_map' will be leaked, |
| add uring_lock to protect 'hash_map'. |
| |
| Fixes: e941894eae31 ("io-wq: make buffered file write hashed work map per-ctx") |
| Reported-by: Hulk Robot <hulkci@huawei.com> |
| Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> |
| Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> |
| Link: https://lore.kernel.org/r/20210720083805.3030730-1-yangyingliang@huawei.com |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/io_uring.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| diff --git a/fs/io_uring.c b/fs/io_uring.c |
| index eeea6b8c8bee..8843f48ace27 100644 |
| --- a/fs/io_uring.c |
| +++ b/fs/io_uring.c |
| @@ -7859,15 +7859,19 @@ static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx, |
| struct io_wq_data data; |
| unsigned int concurrency; |
| |
| + mutex_lock(&ctx->uring_lock); |
| hash = ctx->hash_map; |
| if (!hash) { |
| hash = kzalloc(sizeof(*hash), GFP_KERNEL); |
| - if (!hash) |
| + if (!hash) { |
| + mutex_unlock(&ctx->uring_lock); |
| return ERR_PTR(-ENOMEM); |
| + } |
| refcount_set(&hash->refs, 1); |
| init_waitqueue_head(&hash->wait); |
| ctx->hash_map = hash; |
| } |
| + mutex_unlock(&ctx->uring_lock); |
| |
| data.hash = hash; |
| data.task = task; |
| -- |
| 2.30.2 |
| |