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@xxxxxxxxxx>
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
---
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 0cac361bf6b8..63d3a9c2a2a6 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7899,15 +7899,19 @@ 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;
--
2.25.1
