Yang Yingliang 362a9e6528 io_uring: fix memleak in io_init_wq_offload()
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: e941894eae ("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>
2021-07-20 07:51:47 -06:00
2021-07-11 15:07:40 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 3.4 GiB
Languages
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%